Chrome ECU - Front bank stuck rich

[DrGonzo]

I turned back on the narrowband fuel trim and disconnected the rear O2 sensor. The rear on evoscan stopped logging so the leads are not swapped.

[Greg E]

The sensor itself is probably gummed up with carbon. A taco says the heater in it is bad.

[DrGonzo]

it was a whitish brown color when I pulled it doing the turbo swap. not all black and sooty.

[DrGonzo]

Was talking with Adam on FB and we starting reducing the injector latency with closed loop turned off to try and get the sensor to cycle. After reducing it to a little over half across the entire range the sensor still didn't want to cycle as it should and the rear bank was completely bottomed out. So it looks like the sensor did take a crap out of nowhere. running into town now to get a new one and swap it in.

[DrGonzo]

Installed the new O2 sensor and no change... So it's not the O2 sensor.

[CoopKill]

How confident in the front injectors are you?

[DrGonzo]

Yeah that is my next guess. Going to swap the front and rear injectors tomorrow to see if the issues moves to the rear bank. I'll run them through my ultra sonic cleaner first to see if they are gummed up. Adam thinks it may be a leaking or slow closing injector. I have a few tricks for cleaning out injectors...LOL

I'll know more tomorrow. For now I'm done in the garage. 7 hours of exhaust fumes, even with the garage door half open, is enough for one day.

[DrGonzo]

Got the front injectors out and none where stuck open or leaking. Pressure tested them up to like 60 psi. Cleaned them out in the ultrasonic cleaner and cycled some cleaner through them. Made no difference...

I thought I found an issue as I noticed when you first start the car the front o2 cycles as it should, but as the idle drops down it climbs back rich and stays there. Found the TPS idle switch was not engaging as it should. Went through and adjusted everything on the throttle body again and got the TPS set as it should be. Still having the same issues.

So now I'm letting the car cool and I'm going to swap the front and rear bank injectors to see if it is indeed an injector issue or if it's something else causing it. Should know here in a hour or two.

[DrGonzo]

I got the front and rear injectors swapped, on start-up everything looked good. Once it got to idle at 750 rpm's the rear started going rich and the front dropped out completely but slowly started cycling. just not very much. I went in and turned on long and short fuel trims and started it back up. Again everything look good and then the rear started going rich and the front lean. But then they started to normalize some and the more i ran the better it got. It still have spouts where the rear goes rich but after a min or two it seems to calm back down. I am seeing the front O2 drop out which I don't know why. You can see in the log it drops to straight zero a bit but then comes back. IDK what the hell is going on there.

So below are the logs and the tune I have set just for idle. I have not even driven the car yet as I need to get idle down first. There is only so long I can idle the car before the fumes are just too much even with the garage door half open. So for the night I'm done working on it. If anyone seems anything out of place in the logs or tune please let me know.

Thanks

https://www.dropbox.com/s/bhuf4si5kq...Rom_2.zip?dl=0

[DrGonzo]

Graphed out the front vs rear O2's against the rpm's. this is a two min excerpt from the log I posted.

Black Line - Rear O2
Pink Line - Front O2
Green line - RPM's



Front is cycling as it should. Rear slowly creeps up then drops out, does it again and drops out and stays lean the rest of the time. The drop it RPMS was also something the ECU did and I had to adjust the BISS screw to get it back into normal idle range again. TPS stays at 7.45 the entire time and is never moved. throttle cable is disconnected.