Closed loop fuel trims

I have been doing some logging on my 92 TT. I am using Greg E's setup file on EvoScan 2.9. I have noticed that my front bank fuel trims are all pegged at -25% except for the low whichs will read about -24.5%. The front bank IDC's are about 12+%.
The rear bank looks perfect, all fuel trims are +/- 4.5% and the IDC's are like 2-3% at idle.
Both O2s are new and cycle as the should and there are no major vacuum/boost leaks that I can find.
When in open loop, the IDC's match nicely from front to rear. I have always felt that this car transitions a little odd from closed loop to open.
Any ideas out there on what is going on?
The car also starts weird when warm, sometimes it almost binds like the timing is way advanced, other times it takes a bit of cranking to start and it will start at a low RPM and then come into it. It has very good power under boost, but has always felt a little off in closed loop.

Only mods are...
14 psi
Hotwired stock fuel pump
M2 exhaust
EGR delete
Vac reduction
Cone air filter
No cats at all

Thanks in advance for any help.

Got a cam a tooth off?

They were perfect when I timed it last winter, I will check again to be sure.

When was last time injectors serviced? Can switch banks to see if it makes difference.

Revel in your time

I havent serviced the injectors. I would rather not pull the plenum to switch banks. I plan on getting bigger injectors soon, I was just hoping maybe someone has seen this problem before, its an odd one.

I leaking injector would ruin the fuel trims and cause poor starting..

Pull the plugs and check the colours, if 1 is darker than the rest that's the problem cylinder.

I will dig into it tomorrow.

Small update. Today I disconnected the battery for awhile and then logged without even starting the car. The rear O2 was reading zero and so were the trims but the front O2 was showing like 0.064 volts and the trims started low and slowly climbed towards -25. The IDC's for the rear were zero but the front was about 10% and was climbing up to mid 20s by the time I stopped logging.(car still not even running)
So clearly the ECU is seeing a voltage on the front O2 when it shouldnt and is adjusting the trims and IDCs. Now I need to figure out why the ECU see's this voltage. I will start by unplugging the front O2 and see what happens, I expect to see the voltage still present meaning there is something wrong with the ECU.

You lost me with IDC...? Injector duty cycle is irrelevant with the engine off. 100% of zero is still zero.

If you clear the KAM, and turn the key on, the fuel trims start at zero and begin moving even with the engine off? One side goes high, the other goes low?

Is this STFT that is moving? or both STFT and LTFT?

Your trims should not move with key on engine off and you should deffinitely not see any IDC's recorded!.

That is my point, with the engine OFF I am seeing IDC's for the front bank. They start at about 4% and climb the longer I log.
The STFT and LTFT start near zero and move toward max negative -25. Again with the engine OFF.

The rear bank is doing what it should, all zeros. So upon investigation I noticed the front O2 is reporting a voltage or the ECU is seeing a voltage for the front O2. My theory is this is the problem causing the.IDCs and crazy fuel trims on the front back. I still need to track this further down.
Did it make more sense this time?

My bad guys, the IDCs are zero when not running. Its the front bank pulse width that slowly rises to just over 22 ms. Still doesnt make a bit of sense. I cannot get the front trims to zero out, they always go right to or very close to -25.
At this point I dont 100% trust the logger. The car runs too good for these numbers to be real. I am confused.

I would also suspect the logger... I think all the info you're seeing for the front bank is garbage.

I see you are using the Chrome Evoscan file, Are you using a flash ECU with Chrome?

Using the chrome setup file for evoscan, stock 92 TT ECU. I am using a 1.3 cable and the MMC 1G connection.

I would say that's the problem... There are several parts of that file that are designed to work only with Chrome. You will get bad data in some areas if used with stock ECU.

Evoscan in general is pretty weak on earlier cars... I use Hand Held Halo for PC, or a Palm and MMcd.

Ok man, thanks for the reassurance.

Palm and MMCD has always been fine on my 1st Gen.

FWIW, I see some voltage on the front O2 sensor with the KOEO as well. Im running a 99 ECU with Chrome and I see it both with EvoScan and the tactrix logging so I know its not the logger. havent tried unplugging the sensor yet to see if the voltage goes to zero though.

The voltage from the O2 proved to not be the issue. I unplugged all kinds of shit and still saw 22 ms of IPW without even running. in closed loop my front IPW is always 12-13 ms higher than the rear. When I go to open loop they even out.
I even connected the front O2 to the the rear O2 harness and nothing changed.