cutting out and backfiring

[99 gs iowa]

i have a boosted 420a with hahn portfueler, when im driving an barely giving it any gas it drives just fine, but soon as i try to give it a little it doesnt pull it just start backfiring like crazy, and my turbo manifold and turbo is glowing red, also have tried changing plugs and coilpack an still didnt help the problem. any ideas?

 

[jayson427]

whats your afr's when your barely on it and when you give it gas? what happens at WOT? something is off in your tune i would guess since its back firing

 

[99 gs iowa]

whats your afr's when your barely on it and when you give it gas? what happens at WOT? something is off in your tune i would guess since its back firing

tune was perfect i even had a shop do it, and at idle its fine but soon as i start to give it a little bit of gas it goes straight to lean the pegs itself out,

 

[jayson427]

what size injectors are you using? is your fuel pump stock and how much boost are you trying to run?

 

[oVaBoost]

boost leak? your not getting enough fuel thats why its leaning out so either tune is off timing of some sort are you over boosting or anything like that?

 

[99 gs iowa]

boost leak? your not getting enough fuel thats why its leaning out so either tune is off timing of some sort are you over boosting or anything like that?

nah its getting boost, defintly not a boost leak, and ive never heard of a tune just randomly going bad,

 

[oVaBoost]

fuel pump could be going bad is it re wired?

 

[bagged420a]

Sounds like your running lean for sure, hince the cutting out and backfiring. Just because a shop "tuned" it doesn't mean that couldn't be a problem. It sounds like you don't have a wideband O2, I would suggest getting one. And like asked above, are you overboosting?

 

[glowryder]

he does have a wide band.. he just doenst pay attention to it

Hes running a wally 255, and yes its been rewired.
He is runing an 8 injector setup . Primaries are stock, 2ndaries are iirc 550s. He has fuel head room.

I didnt know it was glowing red.. deff getting hot and shouldnt be...


I think the tune he had when it was working is good, IE i dont think its the tune persay.

Did you boost leak test or tried to connect to the PF like i mentioned?

My theory is soemthing is up with the PF. either its :
1. PF Not turning on ( EIC could have died, or become unconnected etc)
2. Boost signal to it is messed up (PF not seeing boost, so it doesnt add fuel) < this is why boost leak was suggested.....
3, Lost the tune completely (rare, but ive heard of it. not syre what causes it)
4. Did you check you ML filter?
5. ML could have failed. this would cause fuel cut.

Next, go outside and :

1. Go hook up to the PF via computer, this will tell us if its well, turning on and not dead.
then check MAP A nad B. se if there are numbers there etc. (You probably should have saved the tune somewhere.. :/)

2. Do a boost leak test. make sure the signal line to the PF module isnt pinched, disconected etc. Look at your ML filter...

3. If all that checks out, then we may need to look at the map sensor in the PF module..

*it should be noted, yes he has an unhooked up FCD, however, it was working just fine with out, so it wasnt installed.

 

[GSTurbo1]

Do you have a catalytic converter? could be clogged