Sounds like backfiring? Not sure.... Help!!!
03-23-2008, 08:47 PM
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Sounds like backfiring? Not sure.... Help!!! UPDATED!! Okay. This weekend, I put a set of Patriot dual gold springs on the car. I replaced the seats, seals, springs, retainers and keepers and I put an LS6 intake on the car. Everything else motorwise is stock. I drove the car 260 miles this weekend. It has not burnt ANY oil at all. So it would seem that the seals on the valves are okay. I know I haven't bent anything because there is NO ticking, knocking, and I haven't even touched the timing chain yet. (cam and tune care coming up this weekend) Everything is torqued to spec, all rockers are in place perfectly, ****,
I now have what feels like backfiring, a slight surge on accel and a power loss. The backfiring is MAJOR at WOT. It's like awful. Horribly awful. Light accel and cruise are perfect. It kinda feels like the car is too lean... I didn't think springs and and intake would do this much...? The car has been tuned before and was running at a 13:1 a/f before I did all this work.
Can one of you guys please chime in?
[edit]Updated, look down for my 3rd post[/edit]
I now have what feels like backfiring, a slight surge on accel and a power loss. The backfiring is MAJOR at WOT. It's like awful. Horribly awful. Light accel and cruise are perfect. It kinda feels like the car is too lean... I didn't think springs and and intake would do this much...? The car has been tuned before and was running at a 13:1 a/f before I did all this work.
Can one of you guys please chime in?
[edit]Updated, look down for my 3rd post[/edit]
Last edited by sp00rkz; 03-24-2008 at 08:24 PM. Reason: Updating
It's not a miss because I have no ses light
03-23-2008, 09:20 PM
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my 98 did something like that. turns out it was only fouled plugs. could be that or maybe one of the plugs on the coils didn't get clipped all the way. check the plugs on the injectors to but i wouldn't think that would be it.
03-24-2008, 08:23 PM
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Okay. So a friend and I drove it around tonight.
Turns out I was mistaken. It is not a backfire, it is a misfire. Stupid SES light threw me off. Anyways, we ran it hard tonight to bring out the problem. It misses at WOT and mild acceleration when the converter clutch is engaged. Not at any other times. Ever. And it only happens under a load. I rev'd it up to like 5.5k and no misfire... So this leads me to believe that is a a coil pack. We are going to spray the wires down with mist tomorrow morning to rule out a arcing wire. Problem is which coil is it??
It idles like a baby, accelerates great. Even moderate to heavy acceleration is good. Rev's up awesome. However under load it is trash at WOT.
Turns out I was mistaken. It is not a backfire, it is a misfire. Stupid SES light threw me off. Anyways, we ran it hard tonight to bring out the problem. It misses at WOT and mild acceleration when the converter clutch is engaged. Not at any other times. Ever. And it only happens under a load. I rev'd it up to like 5.5k and no misfire... So this leads me to believe that is a a coil pack. We are going to spray the wires down with mist tomorrow morning to rule out a arcing wire. Problem is which coil is it??
It idles like a baby, accelerates great. Even moderate to heavy acceleration is good. Rev's up awesome. However under load it is trash at WOT.
03-24-2008, 09:50 PM
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Well, I mean, I am going to check the plugs tomorrow to see if they are fouled. But, I am going to doubt that they are. A bad plug would cause a misfire at almost all times. Even a slightly fouled one will be noticeable.
Misfire - at high rpm + only when loaded = coil
Misfire - at high rpm + only when loaded = coil
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03-24-2008, 11:02 PM
#10
I had an issue just like yours and fixed it... Did you remove any/all plugs or wires from the plugs?
If so pull them again and replace the plug(s) with the CRACKED porcelain.
(Examine them VERY closely) and use CARE replacing them AND re-installing the boots!!! You may crack one by leaning hard on a boot to get it on.
Electricity takes the easiest most direct path to ground.
Under low load situations combustion pressure is minimal and spark jumps the electrode easily.
Under HIGH load big pressure so spark searches out an alternate route (misfire).
Lemme know...
If so pull them again and replace the plug(s) with the CRACKED porcelain.
(Examine them VERY closely) and use CARE replacing them AND re-installing the boots!!! You may crack one by leaning hard on a boot to get it on.
Electricity takes the easiest most direct path to ground.
Under low load situations combustion pressure is minimal and spark jumps the electrode easily.
Under HIGH load big pressure so spark searches out an alternate route (misfire).
Lemme know...
