Misfire question.
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From: West Chester PA
Misfire question
I have a vehicle made by another manufacturer. It's throwing a misfire code on cylinders 5 and 6, but by far 5 is misfiring the worst. We've noticed, that the cel light only comes on when the car is sitting at idle. After it is driven a while, the cel will go out. I'm confident that the injectors are the problem. I've swapped coils, and the misfire didn't follow the coil, and I've replaced the ignition control module, and no difference with that either. I can replace the injectors, no problem, but I'm just curious as to why they would only throw a code when it's idling.
Thanks.
Matt
Thanks.
Matt
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From: West Chester PA
Misfire question.
I posted this in the FI forum, but thought that since this forum gets more traffic, I'd copy it here too...
I have a vehicle made by another manufacturer. It's throwing a misfire code on cylinders 5 and 6, but by far 5 is misfiring the worst. We've noticed, that the cel light only comes on when the car is sitting for a while at idle. After it is driven a bit, the cel will go out. I'm confident that the injectors are the problem. I've swapped coils, and the misfire didn't follow the coil, and I've replaced the ignition control module, and no difference with that either. I can replace the injectors, no problem, but I'm just curious as to why they would only throw a code when it's idling.
Thanks.
Matt
I have a vehicle made by another manufacturer. It's throwing a misfire code on cylinders 5 and 6, but by far 5 is misfiring the worst. We've noticed, that the cel light only comes on when the car is sitting for a while at idle. After it is driven a bit, the cel will go out. I'm confident that the injectors are the problem. I've swapped coils, and the misfire didn't follow the coil, and I've replaced the ignition control module, and no difference with that either. I can replace the injectors, no problem, but I'm just curious as to why they would only throw a code when it's idling.
Thanks.
Matt
Hotshot
Joined: Oct 2002
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From: The Big, Oregon
Depending on which "B" make it is, it probably uses variations in crankshaft speed to sense a misfire. At higher rpms, the differences smooth out, and the code goes away. Have you checked the plugs and wires?
Postmaster
Joined: Jan 2003
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From: Durham, NC
Originally Posted by Ford_Six
Depending on which "B" make it is, it probably uses variations in crankshaft speed to sense a misfire. At higher rpms, the differences smooth out, and the code goes away. Have you checked the plugs and wires?
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From: West Chester PA
It's a 98 lumina with a 3.1. Yes, I've checked the plugs and wires, and both are new. In fact, I'm on my way to the parts store to get another spark plug just to make sure that I didn't get a bad plug, or have it crack when installing it. There was no CEL light before I changed the plugs/wires, and there wasn't for several months afterwards either. I don't think that it's the plug, but it's easier to just spend a buck or two on a new plug before digging into the injectors. Thanks for the replies.....
Ford_Six - this is actually the answer that I was looking for. I couldn't imagine how the CEL light would come on only after sitting at idle for a few minutes, then go out after driving for a while. I've talked to mechanic friends of mine and they tell me that this engine is notious for having injectors clog. I'm just trying to exhaust all possibilities before replacing them.
Thanks again.
Matt
Ford_Six - this is actually the answer that I was looking for. I couldn't imagine how the CEL light would come on only after sitting at idle for a few minutes, then go out after driving for a while. I've talked to mechanic friends of mine and they tell me that this engine is notious for having injectors clog. I'm just trying to exhaust all possibilities before replacing them.
Thanks again.
Matt
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