Backfiring during high RPMs

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Team_Undisputed
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Backfiring during high RPMs

Postby Team_Undisputed » Mon Oct 13, 2008 5:12 pm

so i just got done installing a new OEM S13 MAF, and a couple of gaskets( turbo extention gasket and downpipe gaskets) and i turned it on and the idle is steady as can be. so then i toke it for a drive and then i decided to push it alittle to like 4k and it started back firing but no bodging just backfire oh and the idle was at 1000rpms. I then poped the hood to make sure everything was ok and i noticed the CAS was maxed out to the top. and now im thinking it might be a timing problem but i dont want to touch that becasue i dont have a timing gun and i dont want to mess it up again. but i really want to make sure so thats where you guys come in. what do you think can be causing the backfire? thanks


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Re: Backfiring during high RPMs (Team_Undisputed)

Postby boro drift » Mon Oct 13, 2008 6:24 pm

Check the simple things first, spark plugs. Its strange that it would be back firing under load. Make sure your plugs are clean and gaped correctly.

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Re: Backfiring during high RPMs (boro drift)

Postby the converted » Tue Oct 14, 2008 2:15 am

Boro I figured you'd be the first one to say check your timing out of anyone. That's where I'd start.

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Re: Backfiring during high RPMs (the converted)

Postby nzmoman » Tue Oct 14, 2008 3:51 am

Also take note as to whether or not you are running really rich is the maf really new or was it a used unit. There is a chance the reading there could be off. After you check your timing thats were I would go. You could be dumping too much fuel.

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Re: Backfiring during high RPMs (the converted)

Postby boro drift » Tue Oct 14, 2008 2:06 pm

the converted wrote:Boro I figured you'd be the first one to say check your timing out of anyone. That's where I'd start.
Yeah, thats what I'd check next. My timing was way retarded and I had no missing or backfiring, so maybe Undisputed's timing is too far advanced.

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Re: Backfiring during high RPMs (Team_Undisputed)

Postby hoddie12 » Tue Oct 14, 2008 3:48 pm

dont worry about the timing light 4 CAS, there should be two groves on the braket an on the head (i think) anyway jst line the two groves up and thats your timing 15 btdc, been a while since i rebuild my old silvia so im goin on memory

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Re: Backfiring during high RPMs (hoddie12)

Postby boro drift » Tue Oct 14, 2008 6:40 pm

hoddie12 wrote:dont worry about the timing light 4 CAS, there should be two groves on the braket an on the head (i think) anyway jst line the two groves up and thats your timing 15 btdc, been a while since i rebuild my old silvia so im goin on memory

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Re: Backfiring during high RPMs (boro drift)

Postby Team_Undisputed » Tue Oct 14, 2008 8:09 pm

thanks for the replies guys so i took off my spark plugs today and i had the BKR6EIX-11 #3674 spark plugs and they had already been pre gapped to 0.40 and ive been reading that i should use the BKR7EIX #6418 spark plugs that are already gapped to 0.30 which is the corrrect gap for a SR20 correct? here are the ones that im talking about getting http://www.frsport.com/NGK-Iri....html

is there anyway that any autozone/checkers or any in town store might carry the exact spark plugs that frsport sales?? or do i have to order them from frsport?

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Re: Backfiring during high RPMs (Team_Undisputed)

Postby Team_Undisputed » Wed Oct 15, 2008 1:59 pm

bump anyone?

oh so today i went to get my timing put back on what it used to be and i found out it was 15 degrees off lol but now my car runs like crap it sounds like a frieking STi and the engine and the whole car shake while at idle so im guessing spark plug problem right because the plugs i have now are gapped to 0.40 can anyone clarify this? thnks

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Re: Backfiring during high RPMs (Team_Undisputed)

Postby boro drift » Wed Oct 15, 2008 2:13 pm

Just make damn sure your car is in timing mode and idling arouond 850 rpm when your timing light is on 15deg.

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Re: Backfiring during high RPMs (boro drift)

Postby Team_Undisputed » Wed Oct 15, 2008 3:24 pm

boro drift wrote:Just make damn sure your car is in timing mode and idling arouond 850 rpm when your timing light is on 15deg.
yeah it was in timing mode and it was idleing fine at 850 just when i drove i did not feel a pull and now it sounds exctly like STi i need some help lol probley spark plu problem right?

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Re: Backfiring during high RPMs (Team_Undisputed)

Postby boro drift » Wed Oct 15, 2008 4:15 pm

Besides the plugs, I would do a boost leak test. My car was doing the same thing except at cruising speed (light to medium load) it would backfire and miss. Turned out I had a major vacuum leak.

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Re: Backfiring during high RPMs (boro drift)

Postby Team_Undisputed » Wed Oct 15, 2008 4:38 pm

boro drift wrote:Besides the plugs, I would do a boost leak test. My car was doing the same thing except at cruising speed (light to medium load) it would backfire and miss. Turned out I had a major vacuum leak.
thanks for the help man. i changed alot of my gaskets all the main ones( exhaust manifold gasket, 4 bolt turbo gasket, turbo arm gasket and both the downpipe gaskets but i will check for leaks does anyone have the link of the thread that showed how to check for boost leaks? i saw a while back

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Re: Backfiring during high RPMs (Team_Undisputed)

Postby Team_Undisputed » Wed Oct 15, 2008 9:19 pm

ok so today at idle the car got shaky (i mean the WHOLE car lol) and when i would rev it at idle it would still sound like a STi and it would backfire everytime i would rev up, also when you would take a whiff of the exhaust when idleing you could smell alot of burnt gas, and then i thought it might be a injector problem so i unplugged the harness one by one and yet the 2nd injector (counting from left to right) was the bad one i pop it out and there is a tiny puddle in the hole where it was before. and then i was inspecting the injector and it falls...FAIL... and the yellow plastic top breaks so i have to get a new injector now and do you guys think that could have been causing the problem the same thing had happened before. injector problem?

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Re: Backfiring during high RPMs (Team_Undisputed)

Postby boro drift » Thu Oct 16, 2008 7:02 pm

Team_Undisputed wrote:the 2nd injector (counting from left to right) was the bad one i pop it out and there is a tiny puddle in the hole where it was before. and then i was inspecting the injector and it falls...FAIL... and the yellow plastic top breaks so i have to get a new injector now and do you guys think that could have been causing the problem the same thing had happened before. injector problem?
What did the spark plug on that cylinder look like?

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Re: Backfiring during high RPMs (boro drift)

Postby nzmoman » Fri Oct 17, 2008 11:57 am

boro drift wrote:Besides the plugs, I would do a boost leak test. My car was doing the same thing except at cruising speed (light to medium load) it would backfire and miss. Turned out I had a major vacuum leak.
good point. Did you check your BOV for leaks as well? Anything that dumps air out of the system while you are at WOT will cause the problems you listed, especially under warmer temps.

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Re: Backfiring during high RPMs

Postby Sr20 Noob » Mon Nov 16, 2020 10:01 pm

There was a guy on here that said he changed his air filter and stopped the backfire? I read this thread while I was waiting on an approval and now a lot of comments are gone

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Re: Backfiring during high RPMs

Postby Sr20 Noob » Mon Nov 16, 2020 10:46 pm

I've recently had my timing done, my MAF rewired due to corrosion, alternator was rewired due to corrosion as well, the car sat for a while (not sure how long) I bought it and had a clutch put in it which somehow caused the alternator charging relay to blow, not sure how. Other than that I know for a fact she sat for over two years on and off (more off than on) but she runs well for the most part and is at the shop, while my mechanic said he hasn't noticed the backfire I dont believe he's stepped on it hard enough, anyway last time it backfired for me it didn't have an air filter on it and it had a bad battery


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