backfiring

[97_eclipse_gst]

i have a 97 gst with a turbo back exhaust and it back fires often in higer rpms.. it first happened when i put a intake pipe on, but it wasnt that bad but i always babied my car and after a while it started to get worst it was at the point where i couldnt rev over 5 grand ever and more then for when im lucky it is a very loud and violent backfire that has shot flames before. i tried everything to fix it but nothing helped until i got a bent valve that i jus found out about fixed.. and when i got it back last night it was great it was the first time i was able the redline my car it was the best feeling but when i got on it today it started again, does any one have any idea what this can be or has had a simialr problem in the past

 

[97_eclipse_gst]

also if it helps i run 15lbs of boost on 93 octane in a 97 gst wit a 3" full turbo back exhaust any info would help.. thanks alot

 

[95blackGsTurbo]

Do you have a cat or anything like that in it or is it just straight turboback. Usually backfire will cause when the car is running to rich. I am guessing by your mods that you don't have a fuel pressure regulator. I would invest in one of those to regulate fuel much better. Backfiring can burn your valve's so that might be why you had to replace an exhaust valve. I would say it could be your timing but if you got that fixed then I doubt it would be that. How much exhaust do you have. Is it a full exhaust exiting the back of do you having it dumping out somewhere else?

 

[97_eclipse_gst]

yes the full exhaust exits out the back and there is no turbo.. my mechanic said it could possibly be that my injectors are to small and not enough fuel is goin in

 

[-DSM2NR-]

Check for boost leaks and check your plugs. That might be the problem.

 

[97_eclipse_gst]

I had checked for boost leaks because thats what i thought the problem was in the first place. I also changed the spark plugs. I had my exhaust completely checked and fixed, i got a full tune up, checked the timing, And changed the wastegate. But it still backfires very often.

 

[-DSM2NR-]

The wires might be in need of replacement as well.

 

[1gcrazy]

Why do I want to say check the O2 sensor? I'm thinking of it like this. If the O2 sensor went bad when it was cold outside. It would create a rich mixture(to compensate for the denser air) right? Well, it HAS been unusually warm outside(which requires a leaner mixture for the thinner air) ya know? If the sensors bad and the mixtures stuck on rich? What color is the smoke at the high RPM's?

PLEASE someone correct me if i'm totally wrong here?

I have a feeling i'm wrong. Yup, i'm wrong.

 

[97_eclipse_gst]

I was thinking it was the 02 sensor as well. But there is no smoke when it backfires. It is just a violent shaking and a reallly loud backfire noise, Thanks for the input.

 

[Cool Mr Steve]

I was thinking it was the 02 sensor as well. But there is no smoke when it backfires. It is just a violent shaking and a reallly loud backfire noise, Thanks for the input.

Ok, is it a stutter or a series of misfires, or is it a LOUD backfire that feels like your hitting a brick wall and causes the car to shut off? If it is the latter, its fuel cut. If not fuel cut, your probably going to want to (on top of what everyone else said) check your coil pack.

 

[97_eclipse_gst]

Ok it is a very LOUD backfire that feels like im hitting a brick wall. But it doesnt cause the car to shut off. I'll check out the coil pack but what would be the best way to prevent feul cut?

 

[97_eclipse_gst]

My friend suggested to me today that this could also be from a bad sensor most likely a intake sensor, could this be causing the backfiring?

 

[97_eclipse_gst]

My friend told me yesterday that a friend of his had the same backfiring problem with his as mine did. He told me that his vacuum lines were not installed properly or something was wrong with them. Can this cause the car to backfire.

 

[95TalonOwner]

Your BOV could possibly be leaking causing you to run rich. That was my problem, it felt like I would hit a wall every time I would floor it on my 1g. A little adjustment and it ran beautifully at WOT.

It says you have a 1g BOV, maybe you could try crushing it a little bit.

 

[Cool Mr Steve]

Do you have an AFPR for that Walbro pump in your mods list? What size pump is it? What kind of plugs did you swap to when you swapped them? Have you checked your wires? Double and triple check that your boost leak test was done properly as well, and then let us know the results of your tests.

 

[Snobordin8]

You aren't venting the 1g bov are you? When I vented on my last DSM with a TurboXS BOV it would backfire loud as hell inbetween shifts, because it was running so rich. I got over the whole venting thing though.

 

[97_eclipse_gst]

No im not venting my 1g bov, and i think i solved the problem. I got a 144 intake pipe off of ebay a couple of months ago. SO i figured i try to put the stock one back in since the backfiring started around the time i got it. After i put the stock one back in the car felt to be running better and it has not backfired yet. Thanks for all the help with everything it is greatly appreciated.