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ECMlink RESOLVED - What the hell is going on with my car/tune going full lean.?

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1990TSIAWDTALON

Moderator
11,432
8,068
Nov 14, 2013
Independence, Kansas
So I am so tired of fighting with my car that I am going to post a log and see if someone can point to potential problems.

Anyone that has followed my threads knows that I am having issues with my 1gb auto car. I changed the transmission in her and she started giving me issues. She just runs lean. I am not necessarily saying its the pump, I have swapped them out so many times that I can do it in 9 minutes and have the car running (too many times).

I just went for a drive and she just wont richen up. The fuel pressure readings on the log are not good, the circuit has some kind of issue but it is getting 5 volts from the MAF plug but when I test the 2 other wires (sensor and ground) are both showing that they go to ground when I tested the wires with an ohm meter.

Fuel pressure on my gauge shows it is keeping up but IDK what the hell else is going on, maybe extra eyes can pinpoint it. :idontknow:

Please take a look at the log and give me your opinions. I need help and am at my wits end.
Thanks to all of you, I sure appreciate you.

See attached log of the short drive, hoping she wouldn't strand me when I didn't have my phone to call for help :banghead:
Marty
 

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  • log.2021.09.22-03 what is wrong with my car.elg
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i may be way off here but
could it be clogged injectors.
if you have good fuel pressure and your duty cycle and injector on time seem to be increasing normally, but your not getting enough fuel to the cylinder, the only thing i can think of is the injector are clogged.
Isn't that a common problem with ethanol?
 
I have never had an issue with ethanol. Injectors-brand new. Old injectors, exactly the same size and exactly the same thing. I wouldn't ask for help but I have replaced EVERYTHING and I'm still stumped, but I will take any and all suggestions/tips/hints, so thank you Dusty.
I'm so pissed at the car and I guess she is me, that I just walk by her, roll my eyes and say a few cuss words and move on to the next project. :rolleyes:
 
Have you tried turning the boost as low as it will go and see if the problem persists?
I haven't. As low as it will go is 24lbs. The WG is loaded with springs.

I still need to crank the pressure up manually to see the pressure rise to 70 or 80, Mike.
 
I'll make sure I do Nick, thanks!
I am more and more thinking I need to send the ECU in for a once over :thumb:
 
Has this happened ever since you did the transmission swap?
 
My son had that setup also but sold it as it was a bit complicated for him. Lots of options on that ECU for sure!
 
Has this happened ever since you did the transmission swap?
Yep, it sure has. Started running lean. I have not changed the tune in a month or so but back then, I resorted back to my Kevin Jewer base files. It didn't do a thing. He told me before he even looked at the log that I needed to get my injectors cleaned, so I bought new 2150s and had FIC clean my old set for FREE (it is part of the deal if you buy new injectors from them). I am so puzzled guys.
 
Yep, it sure has. Started running lean.

Have you confirmed all the solenoids are working and not causing a fault issue with the tcu. I know the ecu takes some readings from the tcu. Maybe its something inside there that it does not like and wont give the ecu the readings it requires.

If its only done it after the tranny swap i dont think its engine related. Its likely to be something with the box in either signal or sensor the ecu needs to read

Anyway to get the tcu read on software to see what its doing? This will help if its activating sensors and solenoids and pressure through out
 
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I sure can, but I am not on a stock TCU. The trans is entirely on is own standalone and the only signal it pulls is the Speed Signal from the dash in a 1g. When my speedometer cable snapped, my standalone thought I was at a stop and shifted the trans down to 1st very quickly, good thing I was only driving slow down a back street since the car was running bad. If I were at highway speed, that would have been DISATEROUS. So warning to anyone running a standalone that reads the speed sensor, if it goes out, and you are in automatic mode, you are going to shell a trans. I have started just using my push buttons on the wheel and leaving her in manual mode until I swap out dash units (I assume my new cable is not an issue now, but the speedometer is bouncing around like an old one). Thanks Bobby! :thumb:
 
Hey Marty, I shouldn't really comment as I don't have link yet and I can't view your log. But I **JUST** dealt with a random very lean AFR scenario in all cases (especially during cruise) and after checking everything, it appeared my coolant temp sensor was just slightly off-target and reading temps too high, thus causing the ECU to pull fuel and leaning the mixtures out, which in turn caused temps to creep even higher. I'm talking 221-228F constantly no matter what and AFRs cycling between 16.2-17.0! I bought a new non-OEM sensor, compared both at room temp and at let's say 60C, and the old sensor was off by a few degrees and had different resistance.

Ignore this if your temps are fine, but it wont hurt to measure your temp sensor just in case!
 
That is another thing that I haven't looked at so thank you, I will add it to the "to do" list in my car.
Thanks @Kryndon !!!
 
Video of the test drive after installing the new pump. She ran better but was lean if you can see the AFR gauge. It also shows how easy it is to use the shift buttons on the steering wheel. Just a light press and you are in the next gear!
You must be logged in to view this image or video.
 
I was only going 20.......ROFL
 
We talked about this in PMs. But I recommend getting a second in car fuel pressure gauge. To confirm what link is saying. You could plumb you boost gauge for the fuel pressure just to confirm. I'm also a 2g. But can you log ECUboost? As far as the coolant sensor, I would confirm it reads correct resistance with car off to factory spec. Nothing stands out in you log. If you confirmed signal, then Im not to sure what else it can be. I would check all main sensors. Maybe their picking up interference or noise?

I notice that your fuel pressure is 120 at idle but when you go into slight boost the pressure doesn't go up, it goes down. Is this true or false readings? I cant seem to log your omnibar sensor. Also when you go wot, at 5500, is your boostest and actual boost close? I also had to use linear fuel pressure settings. I have a AEM sensor, and it wasn't reading right when selecting it as the input. I would try that as well.

Hope I helped a little. I know we talked before. Have you talked to kevin recently about this issue?
 
Well I'm still very curious also. No solution yet and I just replaced the intake gasket and TB gaskets. I can not think of a single thing I haven't tried to get this car to FUEL UP. If you press the gas, it stays stoich or goes lean. No richening up yet and I just worked on her this last weekend. I honestly don't know what to do to MAKE it super rich and see if she'll drive. I barely made it to the gas station and back she was running so lean, 17 to 19 AFRs. It sucks, I can tell you that!!!
 
Change your injector settings so that the ecu thinks that it is running a smaller injector, maybe yours are not flowing what they should?
 
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