backfiring at low rpm

[Cutlass]

This guy had a problem with his crank sensor/wiring with his WOT backfire
http://www.ls1.com/forums/showthread.php?t=133286

[0rion]

I've seen this be a result of a bad plug wire too. Buddy of mine has a 98 vette that was backfiring. I chased it down and he had a burned plug wire that was arcing to a header. How did you clean the MAF? Did you just spray it off or did you try to wipe the resistors down? Those are extremely fragile.....always just spray them down. It *could* be a vacuum leak but normally that will also show up in the idle. Do you have any exhaust leaks pre O2 sensor? It could also mostly be in your tune. Did you leave the spark plugs installed when doing the headers? Easy to crack the ceramic on those but you said it didn't start until 4-5 months later? I would go over the cheap and easy stuff first like examining the plug wires and make sure they're seated on the coils/plugs good and none are cracked or burned. Then just start working your way up the list from there. If you can get the short and long trims post them up.

[pajeff02]

^^ Agree. Easy check for the OP is to simply open the hood at night and see if anything is arcing around the plug wires. Just move around a bit so you can see things from a couple different angles -- should be able to see just about everything except No. 8 pretty well.

[V8MUSCLE]

new plugs went in, but they went in before the headers went on. the wires are the napa wires, cheep, but ive used them before with good luck. the wires are about a half inch at closest to anything, so i dont think theyre arking, but havent checked at night.

it doesnt backfire multiple times just once around 4.5-5k its at the same rpm both times, but i like to have eyes on the road when im doin stupid stuff like that.

in neutral i have reved to the yellow mark, (5.5k?) with no pops in the past couple weeks, it still has massive low end power, 2k rpm burnouts anytime, probably can go lower, but it sounds like my car is orgasming at that rpm.

i just read through his thread, he doesnt have any of the low rpm problems i have, and it sounds like he has multiple backfires/pops at high rpms. my engine has also never cut of on me because of a backfire.

the engine did turn off once when i missed fourth though, it wouldnt start for about 40ish seconds of trying, when it did the tach did not work for about 15-20 seconds... that was right after the header swap, missed fourth (i know, wtf 4th) think it went to second gear for a split second before i got the clutch in. no new ticks or other noises though, and no rods were sticking out of the engine so i think im in the clear. that was 9-10 months ago.

[JayTA98]

new plugs went in, but they went in before the headers went on. the wires are the napa wires, cheep, but ive used them before with good luck. the wires are about a half inch at closest to anything, so i dont think theyre arking, but havent checked at night.

it doesnt backfire multiple times just once around 4.5-5k its at the same rpm both times, but i like to have eyes on the road when im doin stupid stuff like that.

in neutral i have reved to the yellow mark, (5.5k?) with no pops in the past couple weeks, it still has massive low end power, 2k rpm burnouts anytime, probably can go lower, but it sounds like my car is orgasming at that rpm.

i just read through his thread, he doesnt have any of the low rpm problems i have, and it sounds like he has multiple backfires/pops at high rpms. my engine has also never cut of on me because of a backfire.

the engine did turn off once when i missed fourth though, it wouldnt start for about 40ish seconds of trying, when it did the tach did not work for about 15-20 seconds... that was right after the header swap, missed fourth (i know, wtf 4th) think it went to second gear for a split second before i got the clutch in. no new ticks or other noises though, and no rods were sticking out of the engine so i think im in the clear. that was 9-10 months ago.

Pull your wires out and check them with an ohm meter. i had a bad misfire and my wires looked perfectly fine. When i ohm them out I had 2 wires open. Replaced the wires and the problem was gone.

[V8MUSCLE]

new plugs and wires are gonna go in this winter, i was gonna rebuild the trans, and put a new clutch in, but money is a bitch...

[0rion]

yeah, check those wires. My buddies vette I was talking about really showed no signs of a bad wire on the initial check. They were close enough that the headers had just dried them out enough to crack. I noticed it when I bent the wire going up and down it. I'd also like to see your long term trims to see what they look like. Can you export a log to excel with the scanner?

[Lunatikgixxer]

If you say its on acceleration then its probably the plug wires or plugs. You also said it doesnt do it multiple times... The first thing that came to my mind when i read "I just installed my new headers" was, EXHAUST LEAK. But it seems like the guys and you took that whole equation out of the picture.

[Cutlass]

new plugs went in, but they went in before the headers went on. the wires are the napa wires, cheep, but ive used them before with good luck. the wires are about a half inch at closest to anything, so i dont think theyre arking, but havent checked at night.

it doesnt backfire multiple times just once around 4.5-5k its at the same rpm both times, but i like to have eyes on the road when im doin stupid stuff like that.

in neutral i have reved to the yellow mark, (5.5k?) with no pops in the past couple weeks, it still has massive low end power, 2k rpm burnouts anytime, probably can go lower, but it sounds like my car is orgasming at that rpm.

i just read through his thread, he doesnt have any of the low rpm problems i have, and it sounds like he has multiple backfires/pops at high rpms. my engine has also never cut of on me because of a backfire.

Did you install the headers with the spark plugs in the heads. If so, you could have banged up against one and cracked it. Thats happened to multiple members here.

the engine did turn off once when i missed fourth though, it wouldnt start for about 40ish seconds of trying, when it did the tach did not work for about 15-20 seconds... that was right after the header swap, missed fourth (i know, wtf 4th) think it went to second gear for a split second before i got the clutch in. no new ticks or other noises though, and no rods were sticking out of the engine so i think im in the clear. that was 9-10 months ago.

This may or may not be related to your current problem, but this no start/no tach points directly at a crank or cam sensor issue. Like I said, it may not be related to your current backfire/misfire issue, but keep it in the back of your mind.