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

Installed LTs/backfire

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Old 09-03-2010, 12:46 AM
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Default Installed LTs/backfire

I just finished installing longtubes and i ran them open headers for about an hr. I noticed a huge decrease in low end tq, as well as backfiring when WOT? Are these problems common?
Old 09-03-2010, 12:49 AM
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you sure it not leaking ?
Old 09-03-2010, 02:04 AM
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Needz moar tune. It is common from what I have heard to have some low end loss, the power moved up in higher rpms...
Old 09-03-2010, 02:05 AM
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Are you sure you put the wires on correctly?
Old 09-03-2010, 02:19 AM
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took about a month for the computer to catch up for mine to start back firing when i ran open ypipe.. check plug wires go to the right plugs
Old 09-03-2010, 06:26 AM
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I would be looking at the plugs and wires. There should be no backfiring going on.
Old 09-03-2010, 06:47 AM
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Originally Posted by z28DC
I just finished installing longtubes and i ran them open headers for about an hr. I noticed a huge decrease in low end tq, as well as backfiring when WOT? Are these problems common?
Do you mean open w/no ypipe connected? If so your O2's are probably going crazy tring to richen up the motor and you're propbably also running pig rich?
Old 09-03-2010, 10:12 AM
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Originally Posted by DAVE00
Do you mean open w/no ypipe connected? If so your O2's are probably going crazy tring to richen up the motor and you're propbably also running pig rich?
Yes, i do have a 3" x waiting to go on. w/ mufflers. should this stop the backfiring?
Old 09-03-2010, 10:23 AM
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How far are the O2's from the opening of the collector? Most run a small extnsion either a turn down or something so the fresh air wont make it back up the collector. If the air gets up there The PCM will read lean and like others have said the PCM will be making the fuel mix way to rich.
Old 09-03-2010, 10:39 AM
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Originally Posted by z28DC
Yes, i do have a 3" x waiting to go on. w/ mufflers. should this stop the backfiring?
Unplug your 02's and the PCM will default to OpenLoop. This should resolve your backfiring until you get your ypipe and system on. Let us know if this helps. BTW - What year are you and you really need to update/add your sig so we know what you have.
Old 09-03-2010, 03:37 PM
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93 TA. I put the x on today w/o mufflers and i beleive it stopped the backfire. Will confirm tonight.
Old 09-03-2010, 08:26 PM
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FYI , you are going to HAVE to do a heated o2 conversion..start gathering info now...
i promise
Old 09-04-2010, 12:01 AM
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Originally Posted by defaultexistence
FYI , you are going to HAVE to do a heated o2 conversion..start gathering info now...
i promise
Heated o2?
Old 09-04-2010, 01:35 AM
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Originally Posted by z28DC
Heated o2?
...x2
Old 09-04-2010, 03:25 PM
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Are you still back-fire having issues?
Old 09-04-2010, 03:40 PM
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Not so much, the x eliminated the backfiring, i think it may have once or twice. I haven't drove too much to tell for the most part. Thanks everyone.
Old 09-04-2010, 04:31 PM
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This reads like nothing more than mixed up plug wires.
Old 09-04-2010, 10:35 PM
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Originally Posted by SS RRR
This reads like nothing more than mixed up plug wires.

What plug wires are you reffering to? Maybe my spark plugs?
Old 09-06-2010, 12:41 PM
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Anyone on what plugs? Its only backfiring after 3-5 seconds at WOT, but keep in mind im running an open x pipe. Litterally right where the x is that the two merge is straight open after.



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