having a hard time here

[terry735001]

i would like to go over every thing so maybe some 1 may see some thing i missed to help me
so some years ago i got a PCM for a GM 8.1L motor swap i was doing
its in a very big RV and the guy used HP tuners to set every thing up for me


about 6 months ago i got what i would think to be a spark knock why under load only
i found a ground wire for a fuel injector shorted to ground so the fuel injector was just dumping fuel
i fixed side wire but the knocking was still there
so i installed new /fuel injectors/coil/knock sensors/map sensor/ new MAFS/ plugs and plug wires / fuel filter fuel /psi at 60 . and was still there

rebuilt the motor to get the spark knock to stop . motor shop could not find any thing wrong with the motor
so we are not sure what fixed the knocking sound .. think it was a bad lefter but never know a lefter to make sound under low rpm load only before?

now i am trying to fix
open loop the motor runs fine
As soon as the fuel system goes in to closed loop we can hear a change in the exhaust at any RPM and the exhaust smells gets bad and a looping idle /misfire sound
still running used O2 sensors and 1 seems to lag some but at idle LTFT is only - 5 drive and -4 pasenger and max out of rang is 10 for this motor
closed loop at 1500 rpm LTFT goes to 0 and STFT + or - 3 wave so fuel control looks good but really bad exhaust smell but runs ok lots of power
it seems like its pulling the fuel trims way back but the numbers do not show that
there in no EGR on this system
used auto type scope to make sure all wiring was ok and all input and out puts look good to PCM .fuel injectors drivers in pcm look ok

so i would like to ask . has any 1 seen the fuel maps get out of line over a fuel injector getting stuck on
no codes . cant seem to get mode6 on tourq app but it reads every thing else
i do not have a copy of HPtunes but i do have a copy of the files installed on PCM
does any 1 live around FL or know a place i can take the RV around me to look at it for me

in the end i dont think the fuel injector hurt the motor so it has me thinking that maybe some things been wrong with the PCM for some time .
any help on where to look and what to do that would make the PCM play games like this

thanks for any help

[cobaltssoverbooster]

usually you want to have an injector tested after that kind of failure. shorting an injector to full on could cause the internal coil to overheat and cause flow related issues.

you likely have issues with incorrect idle airflow and transient fueling data causing issues on the 8.1. if it was tuned previously with any mechanical issues present then the data will be incorrect for any fresh engine with no mechanical issues.

[terry735001]

usually you want to have an injector tested after that kind of failure. shorting an injector to full on could cause the internal coil to overheat and cause flow related issues.

you likely have issues with incorrect idle airflow and transient fueling data causing issues on the 8.1. if it was tuned previously with any mechanical issues present then the data will be incorrect for any fresh engine with no mechanical issues.

thanks for any help
it was a mail order PCM so it was installed with motor swap. no tuning why running kind of a plug and play setup
the motor did not have any mechanical issues at the time of PCM install like guessing 4 or 5 years ago so its been running well all this time
motor ran for 30K miles before all this started

thinking a injector was hurt i put a scope on the wiring and could see the injectors where working mechanical but i did install new injectors to make sure fuel flow was ok
new injector are stock flow rates all numbers are the same

any way to reset the airflow and transient fueling data . i have did the unplug power fro a few hrs thing . or is it just drive it for some time to rest mapping? i am not sure how hptunes works

how could the airflow and transient fueling data get out of line . i have ran the motor in the drive way for about 2 hrs here and there for testing and only on the road for 20 mins so not alot of miles

[cobaltssoverbooster]

no way to reset transient data. transient isn't a learning feature, its a coded value you can adjust with software. they would have had to do it prior to shipping the mail order stuff. they would modify it to fit the 8.1 which has different values than an ls.

[terry735001]

thanks again . is there any where here i can post to see if any 1 is around me to give me a hand with this . or what is the lost cost unit here where i can fix this my self ?