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badandy
06-15-2007, 02:57 PM
Car is stuck in open loop. It will not no matter how much I drive and how warm the car is or it is outside go into closed loop. I know Bosch O2's are questionable but I put a new one in because it was free. I have never had one cause this kind of problem...in fact the stocker did the same exact thing. I replaced the coolant temp. sensor and all that I can think of is to replace the thermostat. The weird thing is no codes? Autometer gauge is good and will register stoich at start up and creep it's way to the middle of the green bars and just sort of hover in that area. I will get stoich again under decel but any other throttle input send it right back to the greens and stays there...even at idle.

I'll toss in the thermo when I get home...if that doesn't work...any other ideas?

Oh yeah...stock injectors, SMEC, map and press reg.

Turbodave
06-15-2007, 03:09 PM
Have you looked at the output of the O2 sensor with something other than the autometer gauge? I would try to verify it with a scan tool or DVM. The fact that it's not looging a code makes me wonder if the computer is seeing something different from your gauge.

How is the gauge grounded? On my A/F gauges I always run the ground right to the battery connection rather than just to the dash or body of the car, this seems to give the gauge a cleaner ground.

badandy
06-15-2007, 04:01 PM
Have you looked at the output of the O2 sensor with something other than the autometer gauge? I would try to verify it with a scan tool or DVM. The fact that it's not looging a code makes me wonder if the computer is seeing something different from your gauge.

How is the gauge grounded? On my A/F gauges I always run the ground right to the battery connection rather than just to the dash or body of the car, this seems to give the gauge a cleaner ground.

Yes, I have tapped it with a multimeter...and I have to admit I'm knocking cobwebs out of my head...I did see fluctuation but the numbers were awfully high and didn't "bounce" as much as what I had remembered in the past.

I tried many different grounds and ended up on the intake manifold to firewall ground strap.

The car has a VERY NICE aftermarket aluminum radiator and I'm thinking that maybe that may be causing issues...along with maybe a worn out thermo...but the factory temp gauge sets right about 1/4 which is what I remember from all my other cars.

It's something simple I'm sure...I have just been out of it for so long I'm overlooking the obvious somewhere.

badandy
06-15-2007, 04:23 PM
I would be willing to bet that the replacement O2 took a dump.

GLHSKEN
06-15-2007, 04:27 PM
LOL then change it!!!

badandy
06-15-2007, 04:37 PM
LOL then change it!!!

Easy killer:evil: :p I still think something else is up. I'll swap it out with another and see if I have the same results. It's possible that I spoiled this one as the cam/crank alignment was out of whack when I got the car causing it to run extremely rich.

Maybe I should have bought Whitey back...lol...no, wait...Frank isn't finished re-inventing the wheel yet :lol:

turbovanmanČ
06-15-2007, 04:40 PM
Whats your fuel pressure? running stock injectors?

Bosch are known for sticking, OE or NTK are good ones. See if you can borrow a lab scope or Vantage and check it properly. If it was in open loop all the time, it would be using alot more gas.

badandy
06-15-2007, 04:52 PM
Whats your fuel pressure? running stock injectors?

Bosch are known for sticking, OE or NTK are good ones. See if you can borrow a lab scope or Vantage and check it properly. If it was in open loop all the time, it would be using alot more gas.

I've owned the car almost 2 weeks and have gone through 60 bux in gas!...and it ain't cause my foots been it it either! She hits overboost before I can say "Vaughn's a loser"...lol...(sorry Spanky)

It's definately using up the go go juice...stock injectors, stock reg.

turbovanmanČ
06-15-2007, 05:03 PM
I would either recheck your multimeter or borrow a labscope, they can tell you if your running rich or if the ox is no good.

Have access to a scanner?

Aries_Turbo
06-15-2007, 08:10 PM
you check the TPS voltage?

i had a setup that didnt fluctuate much at idle but then it would bounce at cruise if thats any help.

Brian

sdac guy
06-15-2007, 10:05 PM
The car has a VERY NICE aftermarket aluminum radiator and I'm thinking that maybe that may be causing issues...along with maybe a worn out thermo...but the factory temp gauge sets right about 1/4 which is what I remember from all my other cars. My guess is coolant temp sensor is reading too cold. Note the gauge is off the single wire sensor on the middle front of the head. The coolant temp sensor is the two wire sensor on the thermostat housing. So your gauge can read normal and if the CTS says it is cold, then it will stay in open loop. And if that is the case you may not get a code with it until it is really far off.

Barry

badandy
06-16-2007, 12:00 PM
My guess is coolant temp sensor is reading too cold. Note the gauge is off the single wire sensor on the middle front of the head. The coolant temp sensor is the two wire sensor on the thermostat housing. So your gauge can read normal and if the CTS says it is cold, then it will stay in open loop. And if that is the case you may not get a code with it until it is really far off.

Barry
That was my thoughts. I swapped out the CTS with a new one but I'm thinking it's running too cool. I'll check it out tomorrow.

GLHNSLHT2
06-16-2007, 12:35 PM
make sure all the gauge feed and ground wiring is soldered and ground it directly to the battery. Also a scanner is a good idea. After recent findings I'd ditch the NB gauges and stock sensor and go wideband. The stock NB gauges don't tell you anything about how much fuel you'll really running.

Aries_Turbo
06-16-2007, 02:27 PM
^^^^ hes right. if you look at the actual electrical output curve vs AFR, between .87v and .7 v is anywhere from 9:1 to 14:1.... not enough resolution to tune the car precisely to. now as an indication gauge to make sure the car is cycling in closed loop, its ok for that. :)

Brian

badandy
06-17-2007, 09:22 AM
Okay...

For starters...so that nobody misunderstands...I am not looking for tuning right now as I'm just trying to get the car not to swallow more gas than my old ram!

Update:

Brand new O2...still .9 volts constantly
TPS volts OK
All grounds in good shape and verified.
Pulled SMEC plugs, cleaned them and verified all were making good contact.
Swapped out map with two different known good ones
Swapped out coolant temp sensor...even plugged back in the stocker and took a lighter to it to trip the cooling fan
Thermostat is okay
Stock injectors, stock fuel press reg., 255 pump, fuel pressure was verified as stock.
I even swapped in an adjustable fuel press. reg. and set static at 45 psi and STILL get .9 on the multimeter!

Vaughn and I messed around yesterday and we took some pliers to the incoming fuel line...gave it a good squeeze and the O2 sensor voltage did indeed drop...which tells us the O2 is functioning correctly.

I'm leaning towards the SMEC is bad...I can't think of anything else!

sdac guy
06-17-2007, 11:33 AM
Swapped out coolant temp sensor...even plugged back in the stocker and took a lighter to it to trip the cooling fan Does your fan come on when the engine is idling or sitting in traffic after a romp down the freeway?

If not, that would mean the coolant itself is not getting hot enough to trip the fan. Maybe it is not getting hot enough to go into closed loop. Someone before you didn't put in a low temp thermostat did they? Maybe between that and your super radiator, the coolant isn't getting hot enough. A stock one is a 195.

If the fan cycles by itself when idling, then the problem with open loop is not coolant temp related.

Do you have access to a scan tool? BTW, other than bad fuel economy, how do you know the car is running in open loop all the time?


Barry

badandy
06-17-2007, 01:06 PM
Does your fan come on when the engine is idling or sitting in traffic after a romp down the freeway?

If not, that would mean the coolant itself is not getting hot enough to trip the fan. Maybe it is not getting hot enough to go into closed loop. Someone before you didn't put in a low temp thermostat did they? Maybe between that and your super radiator, the coolant isn't getting hot enough. A stock one is a 195.

If the fan cycles by itself when idling, then the problem with open loop is not coolant temp related.

Do you have access to a scan tool? BTW, other than bad fuel economy, how do you know the car is running in open loop all the time?


Barry

I tricked the computer into thinking the temp. was up by plugging in another CTS while the car was running and holding a lighter to the sensor until the cooling fan came on...then I checked the O2 as well as checked the a/f gauge. The multimeter read .9 and the a/f gauge was pegged.

I do not have access to a scan tool at this time. I know that the car is running open loop all of the time due to the multimeter readings and the a/f gauge which I have verified as being accurate enough to use to diagnose the problem.

sdac guy
06-17-2007, 02:01 PM
I tricked the computer into thinking the temp. was up by plugging in another CTS while the car was running and holding a lighter to the sensor until the cooling fan came on...then I checked the O2 as well as checked the a/f gauge. The multimeter read .9 and the a/f gauge was pegged.

I do not have access to a scan tool at this time. I know that the car is running open loop all of the time due to the multimeter readings and the a/f gauge which I have verified as being accurate enough to use to diagnose the problem.

So does the fan cycle when the engine is hot & idling for a while?

Barry

badandy
06-17-2007, 02:39 PM
So does the fan cycle when the engine is hot & idling for a while?

Barry

Yes it does cycle. I previously simulated this test by using a spare coolant temp sensor and holding a lighter to it to get it hot. Nothing changes the O2 voltage which leads me to believe the computer is driving the injector duty cycle to too high of a pulse width

skunkwork
06-17-2007, 04:32 PM
Hey guys, I am the previous owner of the csxt in question here. I did put in a lower temp thermostat when I first got the car cause the one in it was stuck open, @ the time it was the only one I could find. I do have a scan tool for the car, if you want to bring it back I can put it on it, the last time I checked it the only code that came up was for overboost. The car did have a adj fuel pressure reg. from foward motion on it, never really liked it all that much though. I NEVER had it over heat in traffic or after a hard run, an the electric fan always came on an cooled it down in a hurry.

badandy
06-17-2007, 04:46 PM
Hey guys, I am the previous owner of the csxt in question here. I did put in a lower temp thermostat when I first got the car cause the one in it was stuck open, @ the time it was the only one I could find. I do have a scan tool for the car, if you want to bring it back I can put it on it, the last time I checked it the only code that came up was for overboost. The car did have a adj fuel pressure reg. from foward motion on it, never really liked it all that much though. I NEVER had it over heat in traffic or after a hard run, an the electric fan always came on an cooled it down in a hurry.

Hey Anthony:)

The thermostat isn't the problem. The O2 voltage reads as if the car was at full throttle (when it ignores the O2 sensor). It just drinks the gas and smells extremely rich out the tailpipe. It seems as if the injector duty cycle is much too long in duration. I pulled the adjustable regulator off the car to return it back to stock as much as possible to help diagnose the problem. The fuel pressure with the adjustable regulator at static was 45 psi...a stock regulator at static is 55 psi...quite a big difference! Even w/10 psi less fuel pressure on stock injectors the O2 voltage stays at .9!

You can read in the previous posts all of things I have tried. It just baffles me!??

This scan tool you have....can we read voltages while driving?

skunkwork
06-17-2007, 05:25 PM
I don`t think it will, it`s a otc scanner, the computer in the car is very limited as what you can do w/ it, you can do a engine runnin test an a engine off test. You can test relays an stuff like that an different sensors but it doesn`t tell ya alot. It basically would tell you it was runnin rich but it wouldn`t tell you the voltage or anything like that. Like I said the older chrysler computers are limited as to what info it sends to the scanner, you can put it on a GM car an you can do all kinds of stuff w/ the computer where as the chrysler won`t . As far as reading voltage while driving, it won`t do that, it`s not like the obd2 systems where the plug is inside the car an you can test while driving. If ya want I can put it on the car an see if it helps ya out.

GLHNSLHT2
06-17-2007, 05:39 PM
My OTC 2000 will read the O2 voltage while driving.

skunkwork
06-17-2007, 05:50 PM
I can`t remember what model my otc is, it`s a older model, I very rarely use it any more, mainly cause everything now is OBD2, it won`t check ODB2 systems. I`ll check an see as to what model it is.

sdac guy
06-17-2007, 06:36 PM
Yes it does cycle. I previously simulated this test by using a spare coolant temp sensor and holding a lighter to it to get it hot. Nothing changes the O2 voltage which leads me to believe the computer is driving the injector duty cycle to too high of a pulse width No no. I am not asking about you testing it with a lighter.

Take your car for a drive, long enough to get the engine hot. Bring it home and open the hood. Wait 10 minutes with the car idling. The fan should cycle on and off. Have you seen your car do this? That is what I am asking.

If the fan cycles on an off while the car is sitting idling, then it is NOT a coolant temp related problem so that can be ruled out.

If the fan does not cycle on and off, then there may be a coolant temp related problem keeping it in open loop. I looked for my reference on this and can't seem to find it amongst all the SDAC-17 junk around here, but IIRC the coolant has to get to 180 for the system to go into closed loop. The fan cycles above 200 degrees. So if the fan cycles normally, then it is not the coolant temp keeping it in open loop.

Also, the reason I asked how you knew it was actually in open loop, is that the coolant temp is just about the only thing that can keep it in open loop without setting a fault code.

So it either is in open loop which explains the running rich, or you just have a calibration problem, and if that is the case then the next question is, how much vacuum does the car draw at idle or at cruise. As less than 8 inches of vacuum will make it run pig rich.

Barry


Barry

skunkwork
06-17-2007, 06:36 PM
Mine is a mac-logic et400-95, made buy otc, manual says on 87-88 chrysler O2 test all you can do is a key on eng. running test, an all that`ll is that it`s running rich or lean, nothing elese.

badandy
06-17-2007, 06:50 PM
No no. I am not asking about you testing it with a lighter.

Take your car for a drive, long enough to get the engine hot. Bring it home and open the hood. Wait 10 minutes with the car idling. The fan should cycle on and off. Have you seen your car do this? That is what I am asking.

If the fan cycles on an off while the car is sitting idling, then it is NOT a coolant temp related problem so that can be ruled out.

If the fan does not cycle on and off, then there may be a coolant temp related problem keeping it in open loop. I looked for my reference on this and can't seem to find it amongst all the SDAC-17 junk around here, but IIRC the coolant has to get to 180 for the system to go into closed loop. The fan cycles above 200 degrees. So if the fan cycles normally, then it is not the coolant temp keeping it in open loop.

Barry

I understand...what I am saying is I have done both...driven it and let it get warm until the fan cuts on as well as the other...both times it never went into closed loop. I have been driving the car everyday and it cycles the fan as normal.

sdac guy
06-17-2007, 06:53 PM
I understand...what I am saying is I have done both...driven it and let it get warm until the fan cuts on as well as the other...both times it never went into closed loop. I have been driving the car everyday and it cycles the fan as normal.

Okay, then time to move away from coolant temp. I edited my last post with more explanation (you answer too quickly :D ) but here it is again ...

Also, the reason I asked how you knew it was actually in open loop, is that the coolant temp is just about the only thing that can keep it in open loop without setting a fault code.

So it either is in open loop which explains the running rich, or you just have a calibration problem, and if that is the case then the next question is, how much vacuum does the car draw at idle or at cruise. As less than 8 inches of vacuum will make it run pig rich.

Barry

Tony Hanna
06-17-2007, 07:38 PM
Andy,
I know you've said 3 times that it has stock injectors, but I cant get over how much your problem sounds like running a set of +20's on stock fuel pressure. I'll take the heat for asking a stupid question, but are you absolutely sure those are stock injectors? If not, it might be worth the time to compare the #'s to what's listed on Gary D's site and find out exactly what you've got.

badandy
06-17-2007, 07:42 PM
Okay, then time to move away from coolant temp. I edited my last post with more explanation (you answer too quickly :D ) but here it is again ...

Also, the reason I asked how you knew it was actually in open loop, is that the coolant temp is just about the only thing that can keep it in open loop without setting a fault code.

So it either is in open loop which explains the running rich, or you just have a calibration problem, and if that is the case then the next question is, how much vacuum does the car draw at idle or at cruise. As less than 8 inches of vacuum will make it run pig rich.

Barry

Barry, you are always a help! It runs 20"

badandy
06-17-2007, 07:44 PM
Andy,
I know you've said 3 times that it has stock injectors, but I cant get over how much your problem sounds like running a set of +20's on stock fuel pressure. I'll take the heat for asking a stupid question, but are you absolutely sure those are stock injectors? If not, it might be worth the time to compare the #'s to what's listed on Gary D's site and find out exactly what you've got.


3 different sets of TII injectors:( I have check the p/n's

badandy
06-17-2007, 07:45 PM
I honestly feel like it is in the duty cycle. In all my years of messing with these cars (18 years!) I have not come across anything like this.

Tony Hanna
06-17-2007, 07:51 PM
3 different sets of TII injectors:( I have check the p/n's

Gotcha.
I didn't figure it would be something that simple, but it was bugging me because of the similarity.

badandy
06-17-2007, 08:02 PM
Gotcha.
I didn't figure it would be something that simple, but it was bugging me because of the similarity.

It was a god question Tony. That was one of the first things I went after was injectors...in fact I had one freeze up on me after swapping out from one set to the next.

If I can't get this figured out it will just have to be until I get a calibration in there which I am in the process of. My guess is that it's the stock computer which isn't throwing any codes for this problem BTW....that in itself seems strange to me...and maybe a good indication of where I should be looking.

sdac guy
06-17-2007, 08:11 PM
That's great vacuum.

Do you have another map sensor to try?

Barry

Tony Hanna
06-17-2007, 08:14 PM
I just wonder how it would act if you threw an adjustable regulator on there and started dropping the fuel pressure a little at a time. Granted that wouldn't be a solution to the actual problem, but it would be interesting to see how the computer would react.

badandy
06-18-2007, 09:50 AM
I just wonder how it would act if you threw an adjustable regulator on there and started dropping the fuel pressure a little at a time. Granted that wouldn't be a solution to the actual problem, but it would be interesting to see how the computer would react.

I have one on there now set at 45 psi static....still .9

badandy
06-18-2007, 09:51 AM
That's great vacuum.

Do you have another map sensor to try?

Barry
Vaughn and I tried 3 different maps...all did the same.

sdac guy
06-18-2007, 11:02 AM
Vaughn and I tried 3 different maps...all did the same. Could be a small vacuum leak in the map line. Really need a scan tool to see what the computer thinks the vacuum is (and atmospheric pressure). If you bring the car to SDAC, chances are it will get fixed there. Hey, it worked for the trans at 13 ... :D

Did you measure the 5v supply to the map?

Barry

badandy
06-18-2007, 11:31 AM
Could be a small vacuum leak in the map line. Really need a scan tool to see what the computer thinks the vacuum is (and atmospheric pressure). If you bring the car to SDAC, chances are it will get fixed there. Hey, it worked for the trans at 13 ... :D

Did you measure the 5v supply to the map?

Barry


Hehehe...yeah, I was really trying to avoid that situation again:o

I did replace the vacuum line to the map sensor last week when I got the car. I have not measured the voltage to the map as of yet. I will check on that when I get home:nod:

I might drive the car to SDAC. I was just going to ride up with Vaughn originally...as the cost of gas to get me there will kill my wallet.

badandy
06-18-2007, 01:20 PM
Random thought...

If a 3 wire O2 is unplugged from the harness...ther should still be a voltage reading on the O2 side of the plug correct? One wire is ground, one is 12v, and the other is signal...so, if I unplug and measure the signal on the O2 side of the plug I should get a reading of what the O2 is really seeing right?...likewise...I bet if I measure the SMEC side of the plug I will see that .9 volts constant?

I swear I'm thinking it's the SMEC

MiniMopar
06-18-2007, 01:45 PM
If things are all working correctly and you disconnect the O2, you should measure 0.5V coming from the SMEC and some voltage 0-1V coming from the sensor. Make sure you disconnect the A/F guage when you do this, in case it is related to the problem.

If some external electrical issue was making the O2 show rich and everything else was correct, the engine would run very LEAN as the ECU tries to pull fuel thinking that it has a rich condition.

Even if the ECU thought the engine was too cold, you should get the "too cold too long code" (code 17).

sdac guy
06-18-2007, 02:23 PM
Even if the ECU thought the engine was too cold, you should get the "too cold too long code" (code 17). The fan is cycling so that eliminates any coolant temp too cold issues as the cause.

Barry

badandy
06-18-2007, 04:08 PM
If things are all working correctly and you disconnect the O2, you should measure 0.5V coming from the SMEC and some voltage 0-1V coming from the sensor. Make sure you disconnect the A/F guage when you do this, in case it is related to the problem.

If some external electrical issue was making the O2 show rich and everything else was correct, the engine would run very LEAN as the ECU tries to pull fuel thinking that it has a rich condition.

Even if the ECU thought the engine was too cold, you should get the "too cold too long code" (code 17).

And if I see more than .5v from the SMEC? The last time I tried this I got .9 from the SMEC and .5 from the O2 if I remember correctly...which sent me on the wild goose chase of what was telling the SMEC to go to .9v

How much voltage should I see on the 12v wire? (sounds like a stupid question I know) I measured something like 13.5 which I thought was high...this may not mean squat but just seemed weird.

Tony Hanna
06-18-2007, 04:19 PM
Was the car running when you measured the voltage? It seems like most of the 12v stuff will vary between 11-14 volts depending on wether or not the engine is running, condition of the battery, and condition of the alternator.

badandy
06-18-2007, 04:25 PM
I read a post on TD about a broken wire at the SMEC that was for the voltage regulator...and that person had the same problems as I. I have already pulled the SMEC and inspected the wiring and found no problems however. this was my thinking with the 12v wire to the O2...I was thinking that seemed like unregulated voltage.

badandy
06-18-2007, 04:27 PM
Was the car running when you measured the voltage? It seems like most of the 12v stuff will vary between 11-14 volts depending on wether or not the engine is running, condition of the battery, and condition of the alternator.


Yes it was...it was just surprising is all.

badandy
06-18-2007, 05:59 PM
Okay...

O2 unplugged...car running I get .45 from the SMEC....I get like .01 to .04 from the O2? The car idles much better, doesn't smell like strong gas fumes either...a/f gauge is sitting dead center stoich...flickering a little.

Now that leads me to believe O2...good lord I think this will drive me crazy!

Turbodave
06-18-2007, 06:21 PM
Is the A/F gauge connected to the sensor lead or the engine harness?

Either way I would disconnect the gauge and repeat the above steps before saying it's the sensor that's the problem.

badandy
06-18-2007, 06:30 PM
Is the A/F gauge connected to the sensor lead or the engine harness?

Either way I would disconnect the gauge and repeat the above steps before saying it's the sensor that's the problem.


Done that already too. I have never loved Bosch O2's but I didn't want to be spoiling Mopar O2's trying to sort the car out. I've never had this sort of problem before with them...but I'm skeptical of them at this point.

sdac guy
06-18-2007, 06:48 PM
I read a post on TD about a broken wire at the SMEC that was for the voltage regulator...and that person had the same problems as I. I have already pulled the SMEC and inspected the wiring and found no problems however. this was my thinking with the 12v wire to the O2...I was thinking that seemed like unregulated voltage.

The three wire O2 is just a one wire O2 with a heater added. The ground and 12v are for the heater and the 12v on that lead should be about the same as measured elsewhere (battery, coil, etc.). The four wire O2 added a separate signal ground lead.

What is on the smec lead does not mean snot. There is likely some pull up resistor or circuit that needs the load of the O2 lead to be at a proper level. So I would not put any value on what the smec side O2 lead reads.

Now, the question is, can the O2 sensor lead be read properly without it connected? I don't know. But if it can and you are getting .0 anything, then that is why the car runs rich when it is connected. The closer to 0 volts it is, the leaner the sensor is saying the mix is, and the smec will try to richen it up (as Russ pointed out a few posts back).

Barry

badandy
06-18-2007, 07:00 PM
The three wire O2 is just a one wire O2 with a heater added. The ground and 12v are for the heater and the 12v on that lead should be about the same as measured elsewhere (battery, coil, etc.). The four wire O2 added a separate signal ground lead.

What is on the smec lead does not mean snot. There is likely some pull up resistor or circuit that needs the load of the O2 lead to be at a proper level. So I would not put any value on what the smec side O2 lead reads.

Now, the question is, can the O2 sensor lead be read properly without it connected? I don't know. But if it can and you are getting .0 anything, then that is why the car runs rich when it is connected. The closer to 0 volts it is, the leaner the sensor is saying the mix is, and the smec will try to richen it up (as Russ pointed out a few posts back).

Barry

It's the sensor. I just cut away the the a/f gauge from the wiring and ran the same test I did before...with the same results. With the O2 having a .0 value like you said the computer just ramps up the voltage until it reads .9

I can't believe that's two bad Bosch O2's in a row! What kind of dumb luck is that? I'll nab a Mopar unit and be done with this mess!

badandy
06-18-2007, 07:07 PM
Oh yeah...thanks for all the help guys!:thumb:

Tony Hanna
06-18-2007, 07:31 PM
Glad to hear you got it sorted out!

MiniMopar
06-18-2007, 09:00 PM
What is on the smec lead does not mean snot. There is likely some pull up resistor or circuit that needs the load of the O2 lead to be at a proper level. So I would not put any value on what the smec side O2 lead reads.

It's not a pullup, but rather a soft supply that is supposed to be about 0.5V...in the neutral zone. The idea is that if the sensor becomes disconnected, it won't make the signal read full rich or full lean. That could make the car undriveable, plus the ECU would not know that the open circuit had happened. With the reading stuck in the neutral zone, the ECU can flag the sensor as bad, go into limp-in mode, and throw the code 21.


Now, the question is, can the O2 sensor lead be read properly without it connected? I don't know. But if it can and you are getting .0 anything, then that is why the car runs rich when it is connected. The closer to 0 volts it is, the leaner the sensor is saying the mix is, and the smec will try to richen it up (as Russ pointed out a few posts back).

Yes, it can. The way the current flows through the sensor it acts like a small fuel cell...or battery if you will. :) It does not require any kind of pull-up.

MiniMopar
06-18-2007, 09:01 PM
Hmmm...still doesn't sound like the sensor to me. Good luck.

badandy
07-02-2007, 05:50 PM
Hmmm...still doesn't sound like the sensor to me. Good luck.

And well....as much as I hate to say it I think you might be right. I finally got a Denso unit in the car and I'll admit it is MUCH better however:

1. The voltage still does not toggle at idle...only at cruise with my foot completely off of the accelerator (this never happened before with the Bosch units)

2. When at idle or any time my foot touches the accelerator pedal the voltage just about pegs the gauge.

This o2 seems to be functioning correctly...but still rich at idle and cruise...good on decel for the first time ever though.

badandy
07-08-2007, 01:10 PM
Bump...check out my previous post

GLHNSLHT2
07-08-2007, 01:20 PM
the voltage should go to 0 on decel from higher rpm.

badandy
07-08-2007, 02:10 PM
the voltage should go to 0 on decel from higher rpm.
It does "bounce" during decel. I checked the map voltage at idle and it is .7 with 20 hg of vacuum. With some investigating I have learned that the MP computers did not have O2 feedback at idle...but this one does not appear to be one (how would I tell without a sticker?). Mileage is about 15 mpg driving very conservatively. I understand that maps can be bad without throwing a code. I have swapped maps previously with no results.

I'm lost:mad:

Tony Hanna
07-08-2007, 02:54 PM
Back on the injector side of things for a moment.
This is a CSXT we're dealing with right?
You've made it clear that you're running TII injectors, which should be 33 pph.
But since the '88 CSXT never got the TII treatment, the SMEC should be calibrated for 27 pph TI injectors!

I don't know that this is enough to make that much of a difference, but it would explain some of the rich running. It might be worth throwing a set of the 27 pph's back in it to see how it acts.

GLHNSLHT2
07-08-2007, 09:06 PM
It does "bounce" during decel. I checked the map voltage at idle and it is .7 with 20 hg of vacuum. With some investigating I have learned that the MP computers did not have O2 feedback at idle...but this one does not appear to be one (how would I tell without a sticker?). Mileage is about 15 mpg driving very conservatively. I understand that maps can be bad without throwing a code. I have swapped maps previously with no results.

I'm lost:mad:

The only MP puter that doesn't have O2 feedback is the Super60 puter. Every other MP puter I've had or run the code from has had O2 feedback.

badandy
07-09-2007, 11:25 AM
Back on the injector side of things for a moment.
This is a CSXT we're dealing with right?
You've made it clear that you're running TII injectors, which should be 33 pph.
But since the '88 CSXT never got the TII treatment, the SMEC should be calibrated for 27 pph TI injectors!

I don't know that this is enough to make that much of a difference, but it would explain some of the rich running. It might be worth throwing a set of the 27 pph's back in it to see how it acts.

Tony,

It's worth a shot but *I think* being as it has the 88 T2 upper half that it is indeed supposed to have the 33 pph's in. I am not aware of any later model T1's without T2 injectors.

I have a socketed and cal'd SMEC coming from Selgame sometime soon so swapping over to the 3bar setup will tell the tale. I may borrow a 88 T2 SMEC from Vaughn and swapped it out with my stocker to see if that helps...the gas mileage is killing me!

mw6886
07-09-2007, 12:20 PM
Back on the injector side of things for a moment.
This is a CSXT we're dealing with right?
You've made it clear that you're running TII injectors, which should be 33 pph.
But since the '88 CSXT never got the TII treatment, the SMEC should be calibrated for 27 pph TI injectors!

I don't know that this is enough to make that much of a difference, but it would explain some of the rich running. It might be worth throwing a set of the 27 pph's back in it to see how it acts.

Tony is right. 88 was a bastard year. There were SMEC T1's with 27pph injectors. (CSX-T being one of em!)

Although I would have thought dropping your fuel pressure would have helped it a little, but does not seem to be the case?

badandy
07-09-2007, 12:34 PM
Tony is right. 88 was a bastard year. There were SMEC T1's with 27pph injectors. (CSX-T being one of em!)

Although I would have thought dropping your fuel pressure would have helped it a little, but does not seem to be the case?

No kidding? I never knew that! That explains alot! That means that the injectors that Anthony thought were stockers were not.

Well...I tried to drop the fuel pressure BUT...

A.) It's got one of the old Forward Motion regulators on it and won't drop below 50 psi...and that is probably because of...

B.) It's got a 255 pump in it and a stock return line.

Now here is the thing: I don't have any 27 pph injectors! Booooo! I guess I just need to convert it to 3 bar asap!

I'll keep you guys updated.

P.S. Tony, mw6886, if you guys are right I owe ya!

ShelGame
07-09-2007, 01:17 PM
How is your O2 guage grounded? With a 3-wire sensor, it's possible that the O2 guage ground is messing with the O2 signal. I've had that happen once. Make sure the guage ground goes back to the engine, or just dis-connect the guage and see if the car runs better.

I may be wrong, but I thought all SMECs used a 4-wire O2 anyway? That could be the problem entirely.

badandy
07-09-2007, 01:30 PM
How is your O2 guage grounded? With a 3-wire sensor, it's possible that the O2 guage ground is messing with the O2 signal. I've had that happen once. Make sure the guage ground goes back to the engine, or just dis-connect the guage and see if the car runs better.

I may be wrong, but I thought all SMECs used a 4-wire O2 anyway? That could be the problem entirely.

I have ran it straight to the battery and just about everywhere else I could think of. The O2 actually works correctly now that I am using a stock O2 again. According to the 15 mpg I am getting (putting around!) the O2 gauge is indeed accurate.

Do you think the Socketed SMEC/calibration will be coming soon? If so I will wait...if not I need to do something before I go broke buying gas!

badandy
07-09-2007, 01:31 PM
How is your O2 guage grounded? With a 3-wire sensor, it's possible that the O2 guage ground is messing with the O2 signal. I've had that happen once. Make sure the guage ground goes back to the engine, or just dis-connect the guage and see if the car runs better.

I may be wrong, but I thought all SMECs used a 4-wire O2 anyway? That could be the problem entirely.

Almost forgot...

88 SMEC uses a 3 wire. I don't think 4 wire was used until 89 or 90...somewhere in there. My 91 Daytona Shelby had a 4 wire on it I know.

Tony Hanna
07-09-2007, 02:34 PM
No kidding? I never knew that! That explains alot! That means that the injectors that Anthony thought were stockers were not.

Well...I tried to drop the fuel pressure BUT...

A.) It's got one of the old Forward Motion regulators on it and won't drop below 50 psi...and that is probably because of...

B.) It's got a 255 pump in it and a stock return line.

Now here is the thing: I don't have any 27 pph injectors! Booooo! I guess I just need to convert it to 3 bar asap!

I'll keep you guys updated.

P.S. Tony, mw6886, if you guys are right I owe ya!

Andy,
If you want to try a set, anything out of a log car or '88 TI should do the trick. If you can't find anything locally, I should have a couple sets laying around here. I'll send you a set for the price of shipping if I can find them.:)

badandy
07-09-2007, 02:42 PM
Andy,
If you want to try a set, anything out of a log car or '88 TI should do the trick. If you can't find anything locally, I should have a couple sets laying around here. I'll send you a set for the price of shipping if I can find them.:)
Tony,

I REALLY appreciate the thought. Anthony (previous "T's" owner) several sets laying around.

I remember looking up the original injector P/N (don't have it at the moment) on Russ's site and it was listed as unknown flow rate or something of the sort...so at this moment I am unsure what I have. Maybe I'll go grab it really quick and post it here....

Tony Hanna
07-09-2007, 02:47 PM
Tony,

I REALLY appreciate the thought. Anthony (previous "T's" owner) several sets laying around.

I remember looking up the original injector P/N (don't have it at the moment) on Russ's site and it was listed as unknown flow rate or something of the sort...so at this moment I am unsure what I have. Maybe I'll go grab it really quick and post it here....

Should be 4418475
That's the part # Gary D. has listed for the CSXT injectors. That part # is also listed in another chart as 27pph TI.

ShelGame
07-09-2007, 03:15 PM
I have ran it straight to the battery and just about everywhere else I could think of. The O2 actually works correctly now that I am using a stock O2 again. According to the 15 mpg I am getting (putting around!) the O2 gauge is indeed accurate.

Do you think the Socketed SMEC/calibration will be coming soon? If so I will wait...if not I need to do something before I go broke buying gas!

It went out on Friday via Priority Mail. I think you'll get it today or tomorrow.

ShelGame
07-09-2007, 03:16 PM
Almost forgot...

88 SMEC uses a 3 wire. I don't think 4 wire was used until 89 or 90...somewhere in there. My 91 Daytona Shelby had a 4 wire on it I know.


As does my '89 T1.

badandy
07-09-2007, 03:22 PM
It went out on Friday via Priority Mail. I think you'll get it today or tomorrow.

You rule! Thanks Rob!

badandy
07-09-2007, 05:31 PM
The supposed stock injectors have a p/n of 4418335. Time to do some research.

Tony Hanna
07-10-2007, 06:08 AM
The supposed stock injectors have a p/n of 4418335. Time to do some research.

The chart on Gary's site has that pn listed as "unknown on 89-93 fuel rail, not a good part number."

The 89-93 part leads me to believe that they're 33 pph, not the stock 27's, but I've run across a couple threads on TD (even one started by myself that I'd forgotton about!) that point to the contrary. Strange stuff indeed.:confused:

Frank
07-10-2007, 06:48 AM
Tony,

I REALLY appreciate the thought. Anthony (previous "T's" owner) several sets laying around.

I remember looking up the original injector P/N (don't have it at the moment) on Russ's site and it was listed as unknown flow rate or something of the sort...so at this moment I am unsure what I have. Maybe I'll go grab it really quick and post it here....


Remember that gross rich or lean cannot be read properly.


As for the part number, well not even our KC has that one... http://www.turbo-mopar.com/forums/vbarticles.php?do=article&articleid=20

Let me know what you find so that I can add that part number.

ShelGame
07-10-2007, 08:16 AM
I googled that injector and was able to cross it to a Bosch P/N 0-280-150-819. Do your injectors happen to have a Bosch number on them?

If you look that injector up here (http://users.erols.com/srweiss/tableifc.htm), it shows it as a 22.65lb/hr injector. But, the test pressure isn't shown. If you assume 43.5 psi rated pressure, that's still only a 25.5lb/hr injector at 55psi fuel pressure.

badandy
07-10-2007, 09:22 AM
Remember that gross rich or lean cannot be read properly.


As for the part number, well not even our KC has that one... http://www.turbo-mopar.com/forums/vbarticles.php?do=article&articleid=20

Let me know what you find so that I can add that part number.

Okay, the strange injectors are definately 27 pph's. My apologies to Anthony as they indeed are the stock injector. The P/N threw me off!

Okay...on to the results:

Swapped out the injectors and the car just ran so much better. Better power, better idle, just plain better. I have O2 feedback during everything BUT idle...still steadily holding .9 with no fluctuation.

I suspect the Forward Motion adj. FPR is the culprit here. I can and have previously thrown a stock reg. back in. Can someone tell me what kind of idle fuel press. (WITH vacuum hooked up) an all stock engine would have? My memory is cloudy on this as it's been forever since I have ran anything close to stock pressures. I'm sitting at 50 psi. WITH vacuum hooked up and the car pulls 20 hg of manifold vacuum. I have no vacuum leaks and this source is not "shared". The idle fuel pressure just seems high to me and *I believe* is the cause of the overly rich no O2 feedback condititon at idle. I have heard that there were some problems with these FM regulators but don't remember what the problem was.

Can anyone confirm? I may take the mightyvac and simulate the condition to see how it affects the O2 voltage.

Any input? Ideas?

GLHNSLHT2
07-10-2007, 08:20 PM
why not just disconnect the vacuum and make sure it's reading 55psi? I think it's a 1/2psi reduction for every inch of vacuum. So you should be about 42-45psi at idle with vacuum hooked up.

badandy
07-11-2007, 12:49 PM
why not just disconnect the vacuum and make sure it's reading 55psi? I think it's a 1/2psi reduction for every inch of vacuum. So you should be about 42-45psi at idle with vacuum hooked up.


It is set at 55 psi static. That's what I'm saying...set at 55 psi static with 20 hg of vacuum only brings my idle fuel pressure down to 50...this is why I believe that I am getting almost full rich at idle.

sdac guy
07-11-2007, 03:33 PM
With that much vacuum at idle, a stock regulator would certainly be in the low 40's with the vacuum line connected. So yeah, 50 is a tad high (maybe even more than a tad :D ).


Barry

Aries_Turbo
07-11-2007, 06:35 PM
looks like you need a stock regulator or an accufab. Hopefully the custom cal will work well. :)

Brian

badandy
07-11-2007, 08:04 PM
With that much vacuum at idle, a stock regulator would certainly be in the low 40's with the vacuum line connected. So yeah, 50 is a tad high (maybe even more than a tad :D ).


Barry

Right! but here is the thing...I put the stock regulator back on and it too has 50 psi WITH vacuum connected...so, here is what I think. I think that the 255 pump has so much volume being unused and the factory return line in the "T" is restricting how much can return to the tank...thereby causing a high idle fuel pressure.

I have been up underneath and have not seen any kinks or abnormal bends. I remember having this same problem with the Daytona....although not near as bad.

Make sense?

Aries_Turbo
07-11-2007, 08:54 PM
seems to make sense but I dont have this problem in the k car i dont think (though now im going to check the fuel pressure just for kicks) but yeah I remember the daytona issues back at the washout.

Brian

Tony Hanna
07-12-2007, 01:58 AM
Right! but here is the thing...I put the stock regulator back on and it too has 50 psi WITH vacuum connected...so, here is what I think. I think that the 255 pump has so much volume being unused and the factory return line in the "T" is restricting how much can return to the tank...thereby causing a high idle fuel pressure.

I have been up underneath and have not seen any kinks or abnormal bends. I remember having this same problem with the Daytona....although not near as bad.

Make sense?

Makes perfect sense to me. I also seem to remember somebody upgrading their feed line, and using the stock feed line as the new return. I'd have to guess doing something like that would solve the problem.

sdac guy
07-12-2007, 06:16 AM
Right! but here is the thing...I put the stock regulator back on and it too has 50 psi WITH vacuum connected...so, here is what I think. I think that the 255 pump has so much volume being unused and the factory return line in the "T" is restricting how much can return to the tank...thereby causing a high idle fuel pressure.

I have been up underneath and have not seen any kinks or abnormal bends. I remember having this same problem with the Daytona....although not near as bad.

Make sense? Yep, Yep. I've heard of that problem but it didn't occur to me till you said it. Some folks have to either upgrade the return or as Tony said, upgrade the feed line and use the old feed as the return. But for others, they never have a problem with the stock lines and the 255.

Barry

badandy
07-12-2007, 08:39 AM
Like I said...I went through this with Whitey. I wish someone offered a fuel line "kit" that bundled all neccessary fittings and hoses together...this would reduce down time. Anybody have any idea on everything I need? I should have kept all that info when I did it the last time....dangit!

Aries_Turbo
07-12-2007, 01:09 PM
yeah that would be nice wouldnt it rather than getting under the car with a roll of tubing and a tubing bender. problem is that the stock tank only has a 5/16" outlet. a killer kit would have a stock pump hanger with a 3/8" feed line brazed in with the proper ribs on the line to hold the hose on and a similar 5/6" return. that and all the hoses and a few sections of prebent line (for shipping reasons... connects at certain points with hose so that the line isnt so long... again with the ribs to hold the hose on) and some high quality clamps.

Brian

Tony Hanna
07-12-2007, 06:59 PM
...problem is that the stock tank only has a 5/16" outlet. a killer kit would have a stock pump hanger with a 3/8" feed line brazed in with the proper ribs on the line to hold the hose on...
Brian

That wouldn't be hard even for the average backyard mechanic to pull off. Lines could be attached to a modified stock pickup with HVAC silversolder and a map gas torch, and you can make slightly ugly, but otherwise functional hose barbs with the first stage of a double flaring tool.:thumb:

I've got an old pickup/fuel pump laying out in the building. I may fool with it and see what I can come up with.:)

Aries_Turbo
07-12-2007, 07:21 PM
oh i know. its not for me. its for other folks who arent quite so handy with things. :)

Brian

Tony Hanna
07-12-2007, 07:37 PM
oh i know. its not for me. its for other folks who arent quite so handy with things. :)

Brian

I understand. I just got kind of excited thinking about it because I'm going to be going with a new pump in the Spirit soon anyway. I figured I might as well rework a pickup now, and install it with the new pump so I don't have to drop the tank again later if I want to upgrade the lines.:)

GLHNSLHT2
07-12-2007, 08:00 PM
guess I'll have to check my idle pressure with my 255 and stock FPR. I know it's a bit higher static but not sure how much the reg is pulling with vacuum.

badandy
07-12-2007, 08:10 PM
I understand. I just got kind of excited thinking about it because I'm going to be going with a new pump in the Spirit soon anyway. I figured I might as well rework a pickup now, and install it with the new pump so I don't have to drop the tank again later if I want to upgrade the lines.:)

If someone could fab up one for me I'd be happy to make it worth their while. I could do it myself but I need a pickup assembly first and I don't have one at the moment. This will have to be a 1 day project until I find another car to buy.

GLHSKEN
07-12-2007, 08:12 PM
Andy, swap another stock reg.. (let me know if you need one) This isn't right. As we discussed on the ph.... No rhyme or reason.

badandy
07-12-2007, 10:53 PM
Andy, swap another stock reg.. (let me know if you need one) This isn't right. As we discussed on the ph.... No rhyme or reason.

I'll see if Spanky has one and if not I can score one from Anthony I think...if not I'll send you some money and get you to send me one. I am confused too Ken and here is why...

Out of all the shadows that have installed 255 pumps it doesn't make sense to me that I am the only one that I can find (done A LOT of searching forums) to experience this problem? I remember the Whitey wouldn't drop below the mid to low 40's in pressure due to the big pump on a stock return...but 50 psi?

I am just fearful of washing down the cylinder walls with fuel at that pressure at such low RPM....damn white cars....lol.

GLHNSLHT2
07-12-2007, 11:00 PM
I checked mine. I have a 255, stock reg and stock feed and return lines and +40's. The static pressure is 60 and with the vac line hooked up and 20-22" of HG I'm only getting down to 50psi. This is on my accurate VDO gauge. But I'm pulling out a total of 10psi vs. your 5psi.

badandy
07-12-2007, 11:04 PM
I checked mine. I have a 255, stock reg and stock feed and return lines and +40's. The static pressure is 60 and with the vac line hooked up and 20-22" of HG I'm only getting down to 50psi. This is on my accurate VDO gauge. But I'm pulling out a total of 10psi vs. your 5psi.

Now we are getting somewhere. Question: if you have a stock reg than how is your static 60?...that's 5 lbs. higher than normal. Is this on a Shadow? I would assume most K cars would have very similar restriction on the return accross all the different platforms.

I'm starting to wonder if the return line isn't full of sediment or something.

badandy
07-12-2007, 11:06 PM
Oh yeah...one more thing. I have verified this pressure on two gauges for accuracy.

Tony Hanna
07-12-2007, 11:47 PM
If someone could fab up one for me I'd be happy to make it worth their while. I could do it myself but I need a pickup assembly first and I don't have one at the moment. This will have to be a 1 day project until I find another car to buy.

Andy,
before you go to the trouble of replacing lines, try this:
Unhook your return line from your rail and connect a long piece of larger diameter rubber fuel line running to an empty gas can (clamp it down good to seal). Try to keep the rubber line as straight as possible (definately no kinks).
Now start the car and check to see how low you can get the fuel pressure (just be careful not to let it run long enough to overfill the gas can).

If you still can't get the pressure to drop then it's a regulator problem. If you can get the pressure to drop, it's a return line problem.

badandy
07-12-2007, 11:57 PM
Andy,
before you go to the trouble of replacing lines, try this:
Unhook your return line from your rail and connect a long piece of larger diameter rubber fuel line running to an empty gas can (clamp it down good to seal). Try to keep the rubber line as straight as possible (definately no kinks).
Now start the car and check to see how low you can get the fuel pressure (just be careful not to let it run long enough to overfill the gas can).

If you still can't get the pressure to drop then it's a regulator problem. If you can get the pressure to drop, it's a return line problem.
Yup, gonna do that this weekend!

turbovanmanČ
07-13-2007, 02:27 AM
I am running a 255 on my van, I used a stock one and adjustable version and had a base of 55 then hooked up the vacuum and it drops aprox 5-8 psi. Do what Tony suggested.

GLHNSLHT2
07-15-2007, 11:08 AM
Now we are getting somewhere. Question: if you have a stock reg than how is your static 60?...that's 5 lbs. higher than normal. Is this on a Shadow? I would assume most K cars would have very similar restriction on the return accross all the different platforms.

I'm starting to wonder if the return line isn't full of sediment or something.


When I put the 255 in it bumped the base to 60psi. But for some reason it'll still pull 10lbs of fuel out when I hook up the vac line. This is on my 87 ShelbyZ

shelbyplaya
09-11-2009, 05:51 PM
hummmmm this issue sounds ALOT like my issue! Ive changed everything but Im still runnning rich with no o2 change. I hooked up a scanner and its says everything is working fine except for the .94v from the o2 sensor. all test check out fine as well.... gonna replce the o2 for the 3rd time and see what happends.

also at idle and 190* my injector pulse width is 2.4, is that normal?

shelbyplaya
09-11-2009, 07:11 PM
I installed a 3rd new o2 (NGK this time). How ever it the issue at hand didnt change. How ever I did unplug the break booster vac line and only then did the o2 stard cycling. I re connected the vac line and the motor bogged down and almost stalled. I then reved the motor to 2000 RPM useing the TB only to find that the o2 would not cycle.

I also dissconnected my MSD box thinking it was possably sending a weak spark, but also no change to the issue.

Both of our symptomes seem to be the same. I'm sure we can work togeather to solve these issues!