when i realy tramp on the gas to go my car starts sputtering and backfireing after 5 psi.....but when i roll down the throttel and bring the boost up slow it dosent do this...I thought it might be the plugs but its not they are fine and it only just started doing this a few days ago....the only thing diffrent is i have no cat now...any ideas?

 

Most likely the FMU, when the boost pressure rises quickly it raises fuel pressure really quickly and your car will suddenly run super rich, which most likely explains the backfire.

I couldnt even run mine with the FMU, it wouldnt even let me accelerate normally and it made my car run really crappy. 12:1 was way too much i assume.

 

do you have a BOV hooked up? could be the excess pressure from the intake no? just a guess. it would help to post up what you have installed.

 

Dont think itd be the bov..

What kinda turbo you have there,etc. etc?

 

my set up is......IHI RBH5 turbo, front mount ic, greddy BOV,talon tsi intank pump, zex inline booster pump, mallory RRFPR, SMT6, acell 460cc injectors, running 10psi on stock internals. I thought it might be the boost blowing my spark out but i already had that problem months ago and fixed it. Also thought it could have been my ecu reset and lost the smt6 map so i re downloaded my tune map that dident fix it eather.

 

whats your AFR when this happens?

Im assuming its something fuxored with the AFR, may need a better tune. Either that or your plugs may be bad or your not getting a powerful enough spark, but thats not likely it.

 

its probably your fuel setup that inline pump is not a good idea that tsi pump determines your overall flow rate and that zex pump outdrives it spewing fuel into ur return line causing a bubble of low fuel in between the two pumps what u should do is remove the inline pump and replace it with a single walbro and add a good aeromotive fpr

 

i wish i could help. holy snap though is that even safe? i remember you having photos of your engine bay.

viper may be onto something. i cannot relate, but try to check your coilpack from the wires. other than that yeah it must be the AFR messing around with your electronics. but yeah check the ratio to see if you're running too much fuel. it could also be the larger injectors but then again i'm just shouting out suggestions.

 

yeah i think it might be a fuel issue....I dont have wide band o2 to check my afr so im going to go where my car was tuned and get them to check it out on the dyno...I havent had any problems up untill now so its kind of confusing I turned the boost down today just incase...(I forgot to add I have the Turbo XS manual boost controler) my car is still working great other than the sputtering when i realy hammer down on the throttle.

 

get a wideband I can't stress this enough esp if ur runnin a stock ecu1