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Car back fires while Entering boost

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Old 05-13-2007, 05:06 PM
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Default Car back fires while Entering boost

Well after I fixed the miss everything is ok now other than it backfireing a little as I get on it, I am taking it back to who tuned it next week to look into the tune. I only drove it once untill it started backfireing incase it is running lean or something. Any ideas what may be causeing it? All plugs gapped at .30. O yea I have a rear mount turbo

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Old 05-13-2007, 05:06 PM
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do you have a wideband?
Old 05-13-2007, 05:32 PM
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Originally Posted by RooRnZ28
do you have a wideband?
Nope not yet need to get one
Old 05-13-2007, 05:43 PM
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Possibly rich or lean...wideband should show you something.
Old 05-13-2007, 05:45 PM
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Well I had it tuned a week ago and it was missing on the dyno so I took it home but new wires and checked the plugs and I found the wires were coming out of the 02 plug so I fixed them now it doesnt miss at all, and I tried getting on it and it backfired a lot
Old 05-13-2007, 05:48 PM
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The stock 02 sensor wiring shouldnt affect WOT, the car will drive like crap if it is still tuned closed loop, but shouldnt affect WOT.
Old 05-13-2007, 05:52 PM
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yes, and you need to get a w/b just so you will know your a/f, that way if it was running too lean or rich you could at least go from there. have the tuner look at it again..
Old 05-13-2007, 06:08 PM
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OK the WB02 question was already asked, but are you scanning the car with HPT or EFIlive to get a good view of whats going on in realtime?

Can be too rich or too lean, too much timing etc....

I feel it is essential to have a tuning suite (HPT, EFIlive) when going force inducted as its too easy to blow stuff up if the tune is out of whack.

If you have HPT/EFIlive, then post up a log of whats going on, that'll help get you pointed in the right direction.

Any codes being thrown?
Old 05-13-2007, 06:37 PM
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no codes being thrown.
Old 05-13-2007, 06:53 PM
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I think it will be to lean, bad plugwire or bad sparks.
Check the fuel lines,is all strait, check the fuel pressure under boost.
Take new sparks.

I think it can be that only.

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Old 05-13-2007, 06:59 PM
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Yea checked all plugs and change wires, fuel pressure is fine.
Old 05-14-2007, 11:00 AM
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Is your car tuned with a 2 bar setup? Could it be that the car is getting too much fuel just as you get into boost (assuming you don't have the 2 bar setup), and then as the boost gets to your final setting your getting the right fuel??? Just a thought.
Old 05-15-2007, 09:16 AM
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Which plugs are you running? Might want to try and tighten your plug gap too. Ive seen where the plug was not cold enough and once a colder plug was used, this prob completely went away. You can try a gap of anywhere from 25 to 35 thou

And of course as every1 is stating, you desperately need to check your AFR. Pay attention to AFR, the correct plug config, and WOT timing. You may just need to reduce timing as boost comes on. If your timing is too high at peak boost/peak tq, then it may be retarding a lot.
Old 05-15-2007, 10:03 AM
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Well let me describe everything a little better. I have the plugs gapped about 30. Last week I was getting it tuned, noticed a miss and a stutter check ingine light blinking and service engine light was on .So took the car home checked everything out one plug gap was completely shut prob cause I dropped it while installing it and forgot to recheck the gap. I then replaced the wires, I also noticed my o2 sensor wires were messed up so fixed them. Took the car out no more miss but engine lights still on then one day it backfired and the lights whent out, now its just backfireing, I am taking it back to tuner today, I'm guessing that when I got it tuned befoe it may have only been running on 7 cylinders, so now maybe I am running lean. But I am getting the tune touched up today.
Old 05-15-2007, 10:53 AM
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Backfires thru the intake or thru the exhaust? Probably too rich, fouled plugs, or have an ignition problem.
Old 05-15-2007, 10:59 AM
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Originally Posted by Pro Stock John
Backfires thru the intake or thru the exhaust? Probably too rich, fouled plugs, or have an ignition problem.
o sorry thru the exhaust
Old 05-15-2007, 11:08 AM
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Or the gap closed from detonation..
Old 05-15-2007, 11:33 AM
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I'd first make sure that your 02's are set up right, if they are not working the car will default rich. I'd check them since you said they were 'messed up.'

I'd also recheck plugs.

Then I'd log a/f and see what it's doing.
Old 05-15-2007, 12:00 PM
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yea, I fixed the 02 the wires were coming out of the plug so I siliconed them. Took the plugs out they all look normal.
Old 05-15-2007, 12:21 PM
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Do you have any way to look at scan the car, maybe the 02's are broken, if they are the values at idle won't do anything. If they are fine, they will switch back and forth.


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