LS1 Backfiring when started and sometimes during running.... wat do you think?
03-02-2008, 07:46 PM
#43
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one time when i changed my plugs and cranked it up I had backfiring issues..... thought i had burnt a wire etc...... came out to be a cracked (hairline fracture) in one spark plug
03-02-2008, 07:52 PM
#44
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Peace,
Craig.
03-22-2008, 03:17 PM
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Well guys i traded the xpipe for a off road y pipe (hooker that goes with the headers) and I installed it and fired it up, still runs the same, still throws fire out the back and pops etc. Well ive basically taken the o2 situation out of it. Im thinking either bad coil or timing chain. I can also get it flashed back to stock and see how that goes. I dont know the tune history on the engine but the guy did work for a performance shop and im sure it had a tune atleast once. How can I test the coils on the car? or where should I take them? I have a volt/ohm meter. Thanks for any input or ideas. New video coming soon.
03-24-2008, 07:10 AM
#52
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Three bumps in three hours, please stop.
You have some ideas already like A-Bomb mentioned, but you can't or won't whatever. You need to try every idea, and try again, and read up some more maybe you missed something, and search. But please stop bumping, its only allowed 1 per day. And good luck.
Thanks,
Craig.
You have some ideas already like A-Bomb mentioned, but you can't or won't whatever. You need to try every idea, and try again, and read up some more maybe you missed something, and search. But please stop bumping, its only allowed 1 per day. And good luck.
Thanks,
Craig.
03-24-2008, 09:08 AM
#53
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Trust me ive tried most of the stuff stated, just trying to update with information Ive gotten from doing some of this and after adding the Y-Pipe, which seemed to be what everyone though was wrong, as in open headers but its still happening. Will update after Ive tested the ignition. It was actually 1 Bump, the 2 consecutive posts 8:57/8:58 PM were responding to the guy above me, (no lol, then Any takers, as in would like to swap coils with me)
03-24-2008, 06:37 PM
#54
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Just tested the wires, from what I found, resistance should be around 351 ohms (6in ls1 wire). Here's what I found:
Cylinder
#1 - 392 Ohms
#3 - 398 Ohms
#5 - 394 Ohms
#7 - 400 Ohms
#2 - 393 Ohms
#4 - 390 Ohms
#6 - O.L. (Out of Limit most of the time) Initial reading was around 3,000 and I only got it to read this wire about 3 times in total out of the 30 times of trying. When it did test the other 2 times, it was 386 and 393.
#8 - 380-1700 Ohms was the range for this one, it was in range a couple times but most of the time it was way out of range, initial reading was 980 Ohms.
So what I concluded was that wires 6 and 8 are bad and probably firing only a couple times and causing it to back fire, ill replace those first to see what it helps. I will check plugs next, when they were new though the car acted the same.
I also tested one coil, it had no resistance, which is what I was told it should be.
Cylinder
#1 - 392 Ohms
#3 - 398 Ohms
#5 - 394 Ohms
#7 - 400 Ohms
#2 - 393 Ohms
#4 - 390 Ohms
#6 - O.L. (Out of Limit most of the time) Initial reading was around 3,000 and I only got it to read this wire about 3 times in total out of the 30 times of trying. When it did test the other 2 times, it was 386 and 393.
#8 - 380-1700 Ohms was the range for this one, it was in range a couple times but most of the time it was way out of range, initial reading was 980 Ohms.
So what I concluded was that wires 6 and 8 are bad and probably firing only a couple times and causing it to back fire, ill replace those first to see what it helps. I will check plugs next, when they were new though the car acted the same.
I also tested one coil, it had no resistance, which is what I was told it should be.
03-24-2008, 06:52 PM
#56
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well if replacing the wires doesnt fix it you can always grab a tech 2 and look at the misfire counter and see which cylinders are misfiring. then move the coil from one cylinder that is misfiring to one that isn't missing. then look at the misfire counter again and see if the misfire moved. if it did thats your bad coil. if not time to try something else...
03-24-2008, 06:54 PM
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yea i gotta make sure the obdII port is working and hooked up correctly and then look at the misfire counter. Ill try to replace wires and see how it helps. If it doesnt, thats my next move. I can unplug the o2's, let it run for a minute and warm up to take them out of the equation. anyone know how to test MAF and/or crankshaft sensor? I dont think the MAF is bad but it wont hurt to test it. I know it couldnt possibly be the MAF sensor because ive had several go bad when I had an LT1 and it wouldnt stay running for **** because it switches to speed density. I way I use to test a MAF is to hit the top of it with a screw driver while it was idling, if it dies then it is bad.
03-24-2008, 06:57 PM
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Pull the valve covers off and inspect. I just had a rocker arm bolt back out on me which caused a nasty popping sound while idling.
Its worth a shot and easy to do.
Its worth a shot and easy to do.
