2.5 t1 map sensor code 13

[rtcabal]

hi all-
i've been posting on turbododge, too, so if you've seen that thread, sorry to be redundant.

check engine light coming on in my van just after startup. giving me codes 'map 13' and 'vss 15'. i replaced both and its still happening.

map voltage is .85v,
vacuum between map and baro is 18",
5v map reference checks out.

this is puzzling.
thanks for the help in advance,
taylor

[Turbodave]

Hi Taylor, haven't looked at the tech area on TD.com in a long time so I apologize if the information below is a repeat, hopefully it will solve your problem if it isn't.

Anything that would interfere with the vacuum signal to the MAP sensor can cause that code. Look for damaged vacuum lines going to the MAP and also pull the vacuum line off the fuel pressure regulator and look/smell for traces of fuel into it. I've seen a leaking fuel pressure regulator result in a code 13 a number of times.

As far as the code 15 goes, make sure the speed sensor wiring is clean and not soaked in oil, saturated connectors can cause this code even with a good sensor.

[rtcabal]

thanks. fpr vac line shows no signs of fuel. all the vacuum lines are new, though i checked them (and re-checked) without finding any discrepancy.

its a recently rebuilt motor, was running well, had ironed out most of the kinks, etc. the check engine came on the very first time i got on some sustained boost since getting the van back on the road. nothing crazy: 10 psi or so getting on the highway for a spell. immediately after the light came on and its been in limp mode ever since.

i'm ready to get this kink ironed out without creating any new ones!! thanks...

[MiniMopar]

Are you sure you have a stock turbo (2-bar) MAP and not a TBI MAP sensor? Code 13 means the SMEC is happy with the electrical signal from the sensor, but unhappy with what the sensor is measuring. The '89 T1 SMEC is more sensitive to MAP response (good vacuum plumbing) than earlier models. Since you are getting the code right after startup (I am assuming that you get the CE light), I'm guessing that the issue is more fundamental than that.

[rtcabal]

yes, the map is brand new for a turbo vehicle. also, both my new and old map are giving the same reading, so i don't think its the sensor.
yes, check engine comes on. my vacuum lines are new and i've checked them for breaks several times now. i also am using a vacuum block, so they're pretty clean. i started checking out wiring yesterday, the two hot wires from the map were fine, but i didn't get to finish the ground (chicago got pummelled by rain). the ground breaks into five directions, including the vss, for which i'm also getting a code.

any other ideas?

[Turbodave]

Typically if it was a ground issue I would expect it to have a code 14 instead of a 13. However, I wouldn't rule that out, so checking the ground is still a good idea.

I've heard of other people using vacuum manifolds having the same problem. You may want to try using a different vacuum source for the map and see if that fixes it. I'm assuming that you've got the Baro solenoid still hooked up an it's functioning ok? The code 13 is due to the computer not seeing a change when it compares the pressure in the intake to amospheric pressure, and the 89 SMEC's seem to be really picky about this.

Where in the Chicago area you at? I'm up north new the WI border and we've been getting hit pretty hard with rain all week. I'm ready for some dry weather.

[rtcabal]

the thing is that it ran fine for a week or so with this set-up. vacuum doesn't seem to be the issue, as i've had a gauge between the map and baro and it seems to be normal, especially at idle.

oh, also, its a '90. funny, too, as the map sensor for an 89 is different. in fact, that's what i bought at first, hooked it up, ran like poo. loads of smoke. got the correct one and it does the same thing with the new one and the old one.

what about a bad baro? is there a way to test it? as i recall, it was giving me a 28.?? reading the other day...

i'm in norwest chicago, logan square. there's tree branches (and some full trees) littering all the parks and boulevards. i heard 74mph gusts at wrigley yesterday...
thanks again!

[Turbodave]

The baro solenoid can be tested a few ways, when it's off you should be able to blow through the port from the intake vacuum and the port to the map sensor. If your feeling vacuum on the hose going to the MAP sensor then it's probably not clogged. When it's energized there should be atmospheric pressure going to the MAP, you can energize it with a scan tool, or jumper it with 12v temporarily to test.

[rtcabal]

let me try to get this straight.

i've been reading, at idle, 18" of vacuum between the map and the baro, and exactly the same between the baro and the intake. when the baro solenoid is energized, this should change??

[rtcabal]

also, what voltage is correct coming from the map? under different (loaded) conditions?

thanks a ton...

[rtcabal]

here's an update, i hope it helps.

i traced the ground from the map, thus exhausting map wiring as a problem (right?). the ground is common to many sensors: vss, coolant temp, distributor, etc. i checked (with a diode tester) continuity and made sure that every wire was visually acceptable. is there more i should do in this department?

i hooked up the scantool and went through the 'sensor test mode' some more. here's the readings i got:

mode abbreviation description reading
04 COOL coolant temp (volts) 3.8
COOL coolant temp 145 (and climbing)
11 MAP map pressure 10.8-11.3
MAP map voltage .8-1.5 (idle-2k rpm)
VAC vacuum pressure 17.411
12 BARO barometric pressure 28.212
13 BARR BARO read update ^same^

i included the coolant info because my gauge hasn't worked for a spell (prior to this problem), though i find the info the scantool reads to be logical.

any ideas where to go from here?

[rtcabal]

i put a smec from an '89 (the current one is a '90, which has a different part # for the map sensor) and got a map high voltage code 14 and a lean mixture code 51.

what i'm thinking is that the 90 smec is bad because now the code 13 goes away. the wrong reading coming from the map makes sense because they're different anyhow, which is what would affect the mixture.

what do you think?

[Turbodave]

89 Should be a SMEC, but 90 is an SBEC so they shouldn't be interchangeable.

[turbovanman²]

I don't think the 90 harness will go into a 89 computer and vice versa but anyhow, if you've checked, triple checked then it looks like the computer is bunk. As for map sensors being different, not that I know off, Dodge used the same sensor from 87 to 92 I believe or something like that. I've mix and matched many time with no problems.

[rtcabal]

i need to clarify:

i took a motor from an '89 turbo dodge caravan and put it in a '90 turbo plymouth voyager.

the compputers don't LOOK different, though i don't know the difference between a SMEC and a SBEC.

anyhow, the map sensor has little tabs that correspond to the harness. when i first got a check engine light, i accidentally bought an '89 map sensor at and had to return it due to the fact that the tabs were diffferent. sure enough, when i went back and asked for a '90, the part number was different by a digit.

i'm considering buying ($50) a map for an '89 and seeing what happens. it may be easier than tracking down a new computer. BUT, am i clear on the interchangability of these components?

i think i'm finally getting close.

thanks a ton.
-t

[sdac guy]

i'm considering buying ($50) a map for an '89 and seeing what happens. it may be easier than tracking down a new computer. BUT, am i clear on the interchangability of these components?

As turbovanman said, all the turbo MAP sensors from 87-92 are the same functionally. There may be differences in how they mount or connect (tabs) but they all function identically (electrically).

SMEC's were used in 88 & 89. They have two connectors a 60 pin and a 14 pin. SBEC's came out in 1990, they have a single 60 pin connector. Except for the number of connectors on the boxes, they look nearly identical.

There is one exception to the above, and that was in 1989, the Shelby CSX-VNT used an SBEC. Those computers are very rare and hard to come by though, so I doubt you have an 89 SBEC. I am not aware of any vehicle still using a SMEC in 1990.

i've been reading, at idle, 18" of vacuum between the map and the baro, and exactly the same between the baro and the intake. when the baro solenoid is energized, this should change??

Yes. Most of the time the MAP is reading engine manifold vacuum/boost. When the baro solenoid is energized periodically, it switches the MAP from reading manifold pressure to reading atmospheric pressure through the open barb on the top of the solenoid. The MAP sensor should be connected to the center barb on the solenoid and the manifold vacuum to the bottom barb.

Barry

[rtcabal]

ok. i'm a bozo. i dug up the title and it is an '89; i think i the guy i bought it from called it a '90 and it just stuck in my head. that being said...

the van was running without a check engine light before and after the rebuild. once again, the first time it saw sustained boost was when the CE light came on. the map vacuum has been connected properly, to the center barb on the baro.

bozo move #2: i had the map unplugged when i got the 14 and 51. sorry to make this more difficult.

but, as for a breakthrough, with both smecs it gives me 'map 13', so the computer is not at fault.

keep looking for bad wires? i found one yesterday, not too bad, but had potential to be shorting, and fixing it didn't do doodle...

thanks for chiming in. i obviously need help with this. i have not lost confidence, though!

[sdac guy]

As has been said before, and as is stated here most likely the problem is not electrical, but pneumatic (or vacuum) related. I know you said a couple times you've been through the vacuum already, but remember, you also said the code first came on right after you went into boost the first time on the new build. That would also point to a vacuum line problem as often boost pressure will point out any weak spots in the vacuum line or harness.

Something to try which is also on Russ' site, connect your MAP directly to the intake manifold vacuum source bypassing the solenoids. Then see if the code clears. If it does then it most likely is a problem with the lines to/from the baro solenoid. Remember, the line doesn't need to be broken, it could be a plugged line also causing this. So all the lines associated with the MAP & baro solenoid need to be checked for cracks, breaks, or plugs.

Barry

[rtcabal]

i'm speechless. actually, i've been endlessly exclaiming a three part profanity that starts with 'holy'.

i hooked up a line directly to the map. sure enough, no check engine. i've been over the lines a ton of times, but for some reason, never tried this. obviously i've tried everything else.

i am so grateful for all of the help. looks like i've spent the last week learning about fuel injection. wow.

THANK YOU!!!!!!!!!!!!!!