Turbo LS going into fuel cut for no reason

[93supercoupe]

Hello all,

Ive got this issue where my car is going into a fuel cut after a WOT pull even though its not anywhere near any AFR saftey or oil pressure saftey.

It will pull clean and on the decel it will go full lean and second after that it will throw out a huge back fire (very very short exhaust)

I can see in the log that its going 0 PW/ fuel cut but i dont know why. It will only resume when i go under 2000rpm, which is when the AFR saftey resume RPM is set, but increasing AFR saftey resume rpm has no effect on when it will resume from this issue.

Also, semi related- under normal decel, one bank will go full lean, the other will stay on target. I havent captured this on a log yet, but seems possibly related.

Setup-
twin s366 6.0l LS
2200 injectors
MS3 Ultamite with PNP harness
auto trans
EGO for each bank

Please take a look and chime in!

[jsmcortina]

Are the MSQ and MSL a matching pair?

James

[93supercoupe]

couple days apart, but i dont think ive changed anything major. I know i pulled some timing and fuel.

[whittlebeast]

Is it possible ignition cut has something to do with the pit lane limiter?

[jsmcortina]

As you say, the behaviour in the log looks just like "AFR Safety" but looking at status6 none of the AFR Safety bits are set. The re-activation RPM of 2000 doesn't match up with anything I'm seeing in that MSQ either.

Please SaveAs an MSQ and take a datalog and repeat the issue so they match up precisely. With different days it always makes me wonder if something else might have changed.

James

[93supercoupe]

I can certainly do that, but regardless of where the AFR saftey Resume RPM is set, it still doesnt resume until 2000 RPM.

Also, having the pit lane limiter on or off makes no difference.

[jsmcortina]

I'm pretty sure I've found it.
You've made a mistake on your Oil Pressure settings - you are reading your Fuel pressure input (sensor 2) instead of oil pressure (sensor 1.)
When you release the throttle at higher RPMs, your gauge fuel pressure drops and looks like low oil pressure.

James

[93supercoupe]

James,

Thank you! Im sure thats it. Ill test it after work today.

Maybe that will resolve my 1 bank going full lean, also. If not, ill take a log and post it.

[93supercoupe]

So that solved my backfire issue, but the car still goes full lean for a while even though i see some PW on decel

Also attached is a normal driving log of where only 1 bank goes full lean on decel

Im assuming its related

[jsmcortina]

Are you sure it is real? Try swapping the wideband sensors across and see if that follows.

James

[93supercoupe]

I have no reason to think otherwise. They are very close everywhere else

I can switch them around and test, not hard at all

[jsmcortina]

Or an air leak? (Although with a turbo I would have expected you to hear it.)

James

[kaeman]

the full lean condition is also shown when you have a rich misfire, I have had an issue where the mixture was to rich and the misfires looked like it was running full lean. started taking fuel out of the ve table in the lean section and the afrs started reading correctly, it might be that you are having a bad sparkplug on one bank, which will read way lean... just a thought. it will run well most of the time and then miss when the right conditions show up.... check the gap on the plugs or replace them with some new ones... might fix the problem.