RalphPZ06

Guys: I log "Average Injector PW" in HPTuners and it is reporting bank one different than Bank 2 when I am on boost. The exhaust sounds like it is missing and popping a little on boost as well and the power is definitely not what it should be. I suspect a clogged fuel injector or something like that but I would like to know how that "Average Injector PW" value is determined.

Anyone know?

The car is an STS TT 402 Corvette. I am running in 2Bar SD mode so the O2's cannot have anything to do with this. And whatever it is, it was not doing this a couple of weeks ago and it is getting worse. On the 18th Bank 1 = Bank 2 in the log and now Bank 1 = 12.6msec and Bank 2 = 11.4 msec.

Thanks!

ChrisS@sdpc

You might get a quicker response over on HPT's forum. Can't imagine that is much more complicated than some sample of montiored pulsewidth's. The PCM is the source of the commanded pulsewidth. Of course, nothing ever seems that simple in a GM controller, and I wouldn't be the first time I was wrong.

RalphPZ06

Thanks John: I did hear from HPT that it is based on the commanded AFR with some multiplier of the fuel trims. Since I am in SD mode, that tells me that I likely have a rich or lean condition in one or more cylinders. On inspecting the plugs, one looked rich so I am going to suspect something with one or more injectors and try swapping them between the 2 banks to see if the reported injector PW's swap banks too.

ChrisS@sdpc

Sounds about right (at least I would hope so): monitor airflow (eithe MAF of SD), derive base fuel need based on that and commanded AFR, add in all compensating factors (STFT, LTFT, Voltage, Temp, etc.)

Definitely try swapping the injectors. Quick and easy way to see if the problem moves with the mechanical device. Good luck.

Frost

iTrader: (45)

SD means no MAF, not no 02s

what are your fuel trims locked at when WOT? Sounds like one is locking in positive and offsetting one bank...

RalphPZ06

Good point. I have LTFT turned off and Closed Loop turned off and I did not realize the PCM could still add fuel and could also add it to only one bank. I'll go back and look at the fuel trims. Thanks!

Frost

iTrader: (45)

So you are OLSD, and unless you never cleared/reset the trims in the scanner, you are right, they should have no influence.

More than one person has been tripped up by not logging LTFTs because they were in OL but had previously positive LTFTs that remain. It's easy to forget, try resetting them in your scanner and see how that does.

12secSS

iTrader: (30)

Also ensure that you have STFT disabled, as these can still be active in Open Loop. Log your O2 voltages, STFT, LTFT, as well as the Closed Loop/Open Loop status bit to identify this issue. It sounds like a fuel correction issue that the PCM is doing.

RalphPZ06

Thanks. I will check but that is probably not my issue since I scanned on the 18th with even PW's and on the 31st with uneven PW's using the same config and the car started running badly in the interem. So I think the uneven PW's reported are telling me there is a real issue. I think it might be one or more injectors acting up and I am going to swap them between the 2 banks as soon as I get enough of a break to spend a little time on it.

RalphPZ06

OK Thanks: My current config gets most but not all of that. As I mentioned,
I plan to swap the injectors bank to bank. Interestingly, my wideband is on Bank 2 and I think the problem may be on Bank 1. If the issue is an injector I will know immediately from the wideband when I swap them.

I guess this means I should have dual wideband O2 sensors!