WILDMAN

iTrader: (2)

My EVO is misfiring/backfiring really bad when I put my foot in it (still have boost). Service Engine light popped up as well. Runs fine under normal driving. Has been running excellent, this just started happening. Has anyone out there had this problem? Any help would be appreciated.

Thanks

EvoJimbo

iTrader: (6)

Most likely it is your test pipe causing this.

Evilution VIII

Is it doing it during accelerating? or just when you back off the gas? i see youve gone to a bigger less restrictive exhaust, you might just be hearing normal noises from raw fuel being ignited in the exhaust when you lift.. evolutions run so rich to begin with that even when I had my muffler off of my stock exhaust , driving around, now and then I would hear it pop deaccelerating or shifting.

Kyle M.

Edit note: sorry didnt read your post closely I now see its doing it under acceleration.

N10S

iTrader: (4)

Hmmm... I am having the same problem right now with my Syclone. It sounds more like a mis-fire under acceleration as opposed to a "backfire" condition.

I would immediately think :


1) Ingition misfire due to bad plug, plug wire, or possibly even pre-ignition.
2) A compromised exhaust system, either leaking, or internally damaged (I have seen it, so don't doubt it can happen!)
3) Raw fuel being ingnited in the exhaust system under boost.


Btw - the last thought is based on the fact that I don't see any kind of fuel management being used, so your car is more than likely puking out a lot of unburned combustibles.

Just some ideas...


N10S

Ryanmcd2

Someone posted that This Greddy e-01 will cause problem. do a search and see what comes up.

WILDMAN

iTrader: (2)

Thanks for the input guys. To narrow it down a little further, it is obvious that this is do to misfiring. I don't know if it's related to fuel delivery, spark, or timing. But to reiterate, it was running smooth as silk and just started doing this. The probelm is very severe under acceleration.

ErroR

iTrader: (1)

I had the same problem with my rustang before trading it in. Check the plug wires, one may have come loose.

JRock

I would look forward to having some rumbling pops when letting off the accelerator... sounds like a real sportscar.

Mad_SB

iTrader: (8)

Do you have a fuel cut defensor on it, I saw fcd in your sig, if so what type and why.. as in how much boost are you running?

If you do have an fcd, pull it out and lock the boost in around 20 psi and see whats up..

MalibuJack

iTrader: (5)

I had the same issue (in a friends EVO), It didn't seem like detonation, but felt like fuel cut or boost cut.. In any case, check your settings (in your e-manage or whatever fuel management) its possible as its getting cooler that you are having issues with your tune.. I had to back off on my tune settings 3% and the backfire went away.. This is BAD if it keeps happening even if its not detonation (which it might be) Also check your boost, it could be spiking over 21psi which could cause boost or fuel cut to kick in..

WILDMAN

iTrader: (2)

I don't recall the type of FCD (all Japanese writing). And I have been running around 23lbs boost. It's misfiring/backfiring starting between 8-12 lbs boost.

WILDMAN

iTrader: (2)

I would if I could find them.

WILDMAN

iTrader: (2)

I am not running any fuel management system. I have been running @ 23lbs boost with no problem until now. I put in a FCD because I was experiencing cut-off after I installed the down-pipe.
The misfiring/backfiring starts 8-12lbs boost.

WILDMAN

iTrader: (2)

Thanks for the suggestions

AvatarOfWar

iTrader: (2)

If it's getting cold where you live, it is probably fuel-cut caused by MAF overrun (seeing too much airflow). Try backing down the boost and see if it goes away. If it does, you will need to get a fuel management system to reduce the A/F ratio (which basically overrides the airflow signal being sent from the MAF to the ECU and essentially dials it down). Those of us with cams in colder climates had to switch to bigger injectors - I heard that Buschur was having this problem as well.