cal issues at 4K rpms

[Joe_Van_Duno]

Hoping to get some advice. I'm trying to get my van tuned in, and I'm slowly working my boost levels up, but I've hit a wall. Right now I'm running around 12psi and I'm getting a sputter / slight misfire right around 4,000 rpms. It lasts for 2-300 rpms, then goes away and the van pulls pretty good.

Here's a bad part, my wideband O2 sensor is acting up, so I only have my old narrow band gauge to depend on. Going off of that gauge, I'm good on fuel with one red bar showing before the sputter, then two showing afterwards.

At 10 psi and below, van drives like a dream.

Some relevant mods for my van:

t3/t4 50 trim
Fwd F4 cam (to much cam for my engine, but thats whats in there)
Larger valves
Slight head porting
Injectors are supposed to be +40's but van has always run really rich. I have my current cal scaled for 55 lb injectors.

I'd like to post my cal so those that know might be able to look at it and let me know what they think, but I'm not allowed to post attachments. If anyone would like to look at it I could email it to you, otherwise just some advice like "lower the xxx setting to no more than yyy"" Would be great.

Thanks Joe

[Orangetona]

Hoping to get some advice. I'm trying to get my van tuned in, and I'm slowly working my boost levels up, but I've hit a wall. Right now I'm running around 12psi and I'm getting a sputter / slight misfire right around 4,000 rpms. It lasts for 2-300 rpms, then goes away and the van pulls pretty good.

Here's a bad part, my wideband O2 sensor is acting up, so I only have my old narrow band gauge to depend on. Going off of that gauge, I'm good on fuel with one red bar showing before the sputter, then two showing afterwards.

At 10 psi and below, van drives like a dream.

Some relevant mods for my van:

t3/t4 50 trim
Fwd F4 cam (to much cam for my engine, but thats whats in there)
Larger valves
Slight head porting
Injectors are supposed to be +40's but van has always run really rich. I have my current cal scaled for 55 lb injectors.

I'd like to post my cal so those that know might be able to look at it and let me know what they think, but I'm not allowed to post attachments. If anyone would like to look at it I could email it to you, otherwise just some advice like "lower the xxx setting to no more than yyy"" Would be great.

Thanks Joe

It sounds like your timing is off. Also what narrowband are you using because you seem AWFUL lean. Red bar? Thats like...bad. Or...im completely off base, but my narrowbands, if they were red, it was time to put a piston in.

[Aries_Turbo]

what calibration did you start with?

since youve made changes that affect airflow, (cam, head, turbo) you will be the best candidate for dialing it in correctly.

what narrowband gauge are you using? those things really arent that accurate.

your best bet is to get the wideband working correctly.

now, since youve made airflow changes, youll need to adjust the pumping efficiency table. if its lean at a certain RPM, youll want to add fuel at that RPM. same if its too rich, lean it out at the RPM where it happens.

dont go fooling around with the map fuel tables if all you did was scale them for the injectors. just dial that afr in with the pumping efficiency table.

i wouldnt rule out any mechanical/electrical problems either. everyone is quick to blame a cal when they have all sorts of other problems. green copper wiring, base timing advance wrong, bad grounds, other cobblejobs etc. :)

brian

[ShelGame]

What cal are you starting with and how are you tuning it?

[Joe_Van_Duno]

Okay guys, as for my narrow band gauge, it's one of those 10 lights that start out red, then green, yellow, green, and red again. Top two are red, and are "supposed" to represent .9v and 1.0v. I want to get my wideband working, but it was the first of the month, so as usual bank account is a little to low to justify the 120 my local parts store wanted for a replacement O2 sensor. I'll order one up online for half that price, hopefully before the weekend.



As for the base cal I'm using the turbonator smec 2.5 ATX a105.

[ShelGame]

As for the base cal I'm using the turbonator smec 2.5 ATX a105.

Which version? 16.9?

Are you running anti-lag? Computer controlled boost?

Juts FYI, Anti-lag really can only work with computer controlled boost since the retard amount is based on the difference between the current boost and the boost target. If you are running a MBC, and you did not setup the boost targets in the cal to match your setpoint, then you might get anti-lag retard all the time. Also, you might have too much retard. I know I turned it down in my van, and eventually turned it off (since I was running a stock Garret anyway) due to the driveability...

[cordes]

Weren't you having similar problems back when? If so, that would make me think it isn't a cal problem.

[BadAssPerformance]

Weren't you having similar problems back when? If so, that would make me think it isn't a cal problem.

He hasn't run it ina few years, since SDAC-17 in Pittsburgh maybe?

Joe, didja get ahold of a stock-ish cal to test it out with?

[Joe_Van_Duno]

I responded once, but some some reason it hasn't shown up.

Rob - Yes, I'm running v16.9, I never turned antilag on, and I just double check, it's not selected, and I am running a MBC. If it is a timing issue, which way would I need to go? Advance a little or retard a little.....I'm thinking retarding, but not 100%.

Cordes - You've got me thinking. My initial reaction is that this is different. A few years back my van would get up into boost, then peg my wideband at 10.0, then the car would misfire and if I recall correctly, fall on it's face. It would also set off the check engine light indicating knock. What it's doing now is similar with when it happens, but the van comes back "alive" and pulls hard to redline, but without my wideband working correctly I can't say for sure that it's not going real rich before it misfires. However I don't know if I had any knock, as I just found where to turn the knock feature on last night :(

JT - I'd prefer to not speak of that SDAC...the 17.2 that I ran can be forgotten ;p Although that burnout on the boat ramp was pretty fun. I did get a stock cal, but nothing else that I would need to go back to stock. I have a box of "extra" bolts for my minivan at my dads house that may actually have some parts in it, so I'll check that out when I get up there next.

[cordes]

If you think it's knock, I would pull some timing right there in the WOT table.

[Force Fed Mopar]

Too much retard can make it misfire also. Has to be a lot though. If it's advancing too much, it doesn't really misfire, it pings or knocks, although too much can also cause misfire. It's probably a fuel under boost issue, if it's good everywhere else. Mine had a lean bog coming into boost, had to up the fuel a good bit between 0 and 10 psi.

[Aries_Turbo]

you need to get all your monitoring stuff working before blindly making changes.

wideband, making sure the CEL blink is working or use an OTC scanner.


Mine had a lean bog coming into boost, had to up the fuel a good bit between 0 and 10 psi.

did you dial the pumpingefficiency table in COMPLETELY before messing with the map tables?

everyone goes for those damn map fueling tables when they should keep their grubby little fingers off. :) other than the scaling that happens for different injectors and maybe a safety mod here or there on the FuelPartThrottle table, get away from those tables.

PUMPINGEFFICIENCY FIRST!!!!!!!!!!!!!!!!!!!! on the lowest boost level you can get for safety. that one table effects soooooo many other tables. you can ignore that tables importance and then spend years tinkering with all the other ones trying to get the car to warm up properly, idle properly etc.

brian

[Force Fed Mopar]

Stock head, stock 2-piece, didn't see why I should change it much. I did try it, but it didn't seem to do what I want, plus it didn't lean out anywhere out of boost. It's working good as it is :)

[Aries_Turbo]

FYI i wasnt trying to single you out Rob, it just seems that most folks that i talk to, go straight for the FuelPartThrottle, FuelNoThrottle (AKA FuelBaselineFromMap) and FuelFullThrottle to try to correct issues on modded cars when they didnt touch the PumpingEfficiency table at all.

You cannot lean out the mix at part throttle and not in boost with any of the regular fuel tables mentioned above. you have to adjust the O2 controller stuff so that it seeks a different AFR or at least biases the O2 correction towards more lean or more rich. exactly how to go about this, i dont know exactly.

you want it leaner in vac and cruise, the most effective way ive seen is to use a wideband and scale the narrowband output richer so that the stock ecu pulls some fuel.

when i get my car back on the road, ill do some tinkering and see if i can get it to run leaner and still be safe and richen up when in boost.

now, all that said, i do add some fuel in the part throttle table from 5psi on up. i make it match the fuel throttle table so that when you are using a manual boost controller and you roll off the throttle, it doesnt instantly go lean and kill stuff. :) that kind of thing is fine and adds safety to the calibration.

heres how the bad conversation goes:


Someone - "my car runs like crap. i scaled the tables for 52lb injectors and it ran lean from 15-23psi so i added fuel to the FuelFullThrottle table but it didnt seem to fix everything"

Me - "What mods are done to the car"

Someone - "2.5L, ported head, cam, custom big plenum intake with the pinch behind the injectors removed and matched to the head, stainless tubular header with a merge collectors and a GT3076R, 3" exhaust and a calibration based on the 89T1 cal"

Me - "Did you lower the boost as low as it can go and do some runs to make the pumping efficiency table match the RPM airflow requirements of the modifications that you made?"

Someone - "Whats the pumping efficiency table do? i saw that in there but i didnt know how it worked so i left it alone. I saw that FuelFullThrottle table and i know it was lean at full throttle and 20psi, so i figured that was the table to adjust"

Me - "No, put that table back and do the pumping efficiency table tuning first"

it happens all the time. If the pumping efficiency table is incorrect, it effects all the other tables. ive had folks complain about poor warmup characteristics. they messed with those CurveA, CurveB and CurveC curves all day long and the car still warmed up like crap. taking a few minutes to dial in that pumpingefficiency table fixed 99% of it.

Brian

[Force Fed Mopar]

Yeah I gotcha, no worries.

[Joe_Van_Duno]

Well, I installed my new O2 sensor, and now my wideband is working :) It appears that my ignition timing was the culprit. I'm pretty sure I had to add timing. In the spark advance from map full throttle, I had to move the graph up from -6* to .7* and then the van pulled strong all the way through the gear shift, no knock, and wideband reading 10.2. That looks like a big change in timing, any ideas why?

[Aries_Turbo]

is your distributor set wrong?

thats all i can think of as your previous cal looked stock in the timing department.

Brian

[Joe_Van_Duno]

I double checked my distributor timing and with the ect disconnected it does jump around a bit but it's set between 10-12* If anything I'd say it's set closer to the 10* mark than the 12. Should I bump it up a little and see what happens? I just changed my injector scaling to 58lb injectors and the van is still running 10.0 to 10.2 on the wideband. If I increase the PE table, wouldn't that richen it u even further? Ideal a/f ratio on a wideband is in the 10.7 - 11.2 range correct?

[cordes]

If you increase the PE table it will increase the amount of fuel in that RPM range. 11.5 is about as lean as I like to run.

[Joe_Van_Duno]

Just wanted to post a final update on my van. I think I finally have it running good. My final issues was that I was really adjusting my ignition timing tables far from stock. I read on here about guys running spark plugs gapped at the stock .035 being to big of a gap. So I closed the gap down to .028, put my timing tables back to a stock setting and BINGO!!! no more misfire. I've since played with the timing tables a bit to keep the engine from knocking, but now she's running great.

I put about 100 miles on it last night, not one time did wideband go leaner 10.6 and the knock indicator never lit up.

After a 5 year wait, my van is finally heading to the track :D

Thanks guys for all your help over the past few weeks, months, and years!!! Now, any bets as to how long this transmission will last??? It's a used A413, bone stock, with I'm sure over 100K miles.

[Orangetona]

Could last a while, you never know. They are kinda like a ticking bomb.

Awesome you got it going good. Always feels good huh?

[cordes]

I'm really glad to hear that you have it running well. I can't wait for a report back on times.

[Joe_Van_Duno]

It feels great to be driving it, and it always funny to get the strange looks from people. I've put just under 200 miles on the van since yesterday, all city driving, and averaged 19.8 mpg!!!!! Gotta love it.

[BadAssPerformance]

Good to hear Joe! :thumb:

[Vigo]

Congrats on the time you just posted.