LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Headers installed now getting backfiring.

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Old Jan 29, 2010 | 10:50 AM
  #1  
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Default Headers installed now getting backfiring.

I finally finish installing the LPP headers last night and fired it up this mourning. I was getting crazy backfiring noise. Im thinking maybe I have the a spark plug wire or two in the wrong place...or could it be any of these options:

*I took the ERG off but don't have my block plates on yet
*NO Y pipe installed just the headers with the o2 sensors

My friend said he actually saw sparks shoot out these exhaust under the car when i started it up

Anything else that may cause all this back firing?
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Old Jan 29, 2010 | 10:54 AM
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Almost always a wire on wrong or one damaged.
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Old Jan 29, 2010 | 11:04 AM
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i don't think your suppose to hook your 02s up if u run with open headers to much fresh air right there
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Old Jan 29, 2010 | 11:07 AM
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/\ excellent point.
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Old Jan 29, 2010 | 11:08 AM
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If the headers aren't ceramic coated you shouldn't have a problem with the O2s.

And it is very likely you are burning a wire, spark plug isn't fully seated, or a wire is crossed.
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Old Jan 29, 2010 | 11:11 AM
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Okay thats what Im thinking as well (spark plug or wiring problem)...Been doing this for 2 days now. Im too sore to hop on top of that think again. Maybe tomorrow.
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Old Jan 29, 2010 | 11:11 AM
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Originally Posted by TheTransporter69
i don't think your suppose to hook your 02s up if u run with open headers to much fresh air right there
So too much air could cause back firing?
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Old Jan 29, 2010 | 11:15 AM
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im not sure about back firing, but i read on here that it wont run right or something along those lines. you could try unhooking them and running it see if it still backfires just to eliminate the possibility. Its probably more related to plugs though like everyone else is saying.
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Old Jan 29, 2010 | 12:58 PM
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I ran my car with open headers and it was fine but yes too muh cold air coming back in can mess them up. The first thing I would do is check the plug wire make sure there in the right place and non got burnt also. Plus you need to put get block off plates for the egr that's not going to help anything. And yes flames shooting out the headers is normal when there is no exhaust on there
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Old Jan 29, 2010 | 05:08 PM
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I actually fried my opti in the process of swapping out headers somehow!! my car was backfiring when i started it up w/ the new headers.. i spilled coolant on it im pretty sure.. but yea TRIPLE check ur wires make sure theyre right...
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Old Jan 29, 2010 | 05:17 PM
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You said you removed your egr but don't have block off plates on??
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Old Jan 29, 2010 | 05:26 PM
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Originally Posted by xxRONNIExx
*I took the ERG off but don't have my block plates on yet
Well, that's an intake leak to add to your problems.

The only thing about running open headers is that the O2's are closer to fresh air and their readings will be off. You'll burn rich in closed loop. But it shouldn't cause backfiring. I drove mine for a week with open headers.
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Old Jan 29, 2010 | 07:47 PM
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I'm guessing the headers don't have egr ports? If they do I hope those aren't the plates you're talking about haha
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Old Jan 29, 2010 | 07:50 PM
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No i think he's talking about the block off plates on the back of the intake
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Old Jan 29, 2010 | 08:41 PM
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Originally Posted by bigj2717
No i think he's talking about the block off plates on the back of the intake
Yep thats what Im talking about
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Old Jan 29, 2010 | 09:06 PM
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Yeah well you need to get those and check your plug wires and once that's done I'll bet everything will be back to normal
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Old Jan 29, 2010 | 09:29 PM
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Originally Posted by bigj2717
Yeah well you need to get those and check your plug wires and once that's done I'll bet everything will be back to normal
Couldn't have said it better
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Old Jan 30, 2010 | 07:34 AM
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Originally Posted by xxRONNIExx
I finally finish installing the LPP headers last night and fired it up this mourning. I was getting crazy backfiring noise. Im thinking maybe I have the a spark plug wire or two in the wrong place...or could it be any of these options:

*I took the ERG off but don't have my block plates on yet
*NO Y pipe installed just the headers with the o2 sensors

My friend said he actually saw sparks shoot out these exhaust under the car when i started it up

Anything else that may cause all this back firing?

Theres your problem right there. Good luck and get those plate ASAP
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