Engine stumbling and spark plugs
09-27-2008, 05:49 PM
#1
Melting Slicks
Thread Starter
Engine stumbling and spark plugs
So for the past couple races I've been having an intermittent engine stumbling. It sort of acts like a rev limiter for a second or so and then disappears with the engine continuing on as usual. At first I thought this was a part throttle issue, but at nationals it happened at WOT a couple times.
So, after some searching, I decided that my likely culprits are probably the coil packs, plugs or wires. I pulled the plugs today, most of them looked "OK" but could definitely do with replacing. They were all brownish, with a sort of layer over the tips.
However, when i hit the rearmost cylinder on the drivers side, this happened:
At first I cursed up a storm, thinking I'd have to take off the head to get that thing out, then I realized that the nut was still in there and just unscrewed it the rest of the way. So, on with the questions.
- Is it possible for a plug to crack like that from use? Or did I just oafishly break it when unscrewing it?
- What plugs should I get to replace these?
So, after some searching, I decided that my likely culprits are probably the coil packs, plugs or wires. I pulled the plugs today, most of them looked "OK" but could definitely do with replacing. They were all brownish, with a sort of layer over the tips.
However, when i hit the rearmost cylinder on the drivers side, this happened:
At first I cursed up a storm, thinking I'd have to take off the head to get that thing out, then I realized that the nut was still in there and just unscrewed it the rest of the way. So, on with the questions.
- Is it possible for a plug to crack like that from use? Or did I just oafishly break it when unscrewing it?
- What plugs should I get to replace these?
09-27-2008, 06:18 PM
#2
Safety Car
Wally, I have seen plugs that have been cracked and not noticed. they can cause a miss if used that way it may have been cracked installing it. The best plugs are the Stock replacements. They are actually Denso for about half price!
What you have may be your miss
What you have may be your miss
09-28-2008, 08:45 AM
#3
Drifting
Had the exact problem on my SRF! Finally I found it and one plug was almost broken in half and another was cracked pretty good. The boot was the only thing holding it together.
No way did I cause that installing them either. Right in the middle of a corner it would be like you just disconnected one cylinder momentarily (25% of them in my case!). No idea why this occurs however.
No way did I cause that installing them either. Right in the middle of a corner it would be like you just disconnected one cylinder momentarily (25% of them in my case!). No idea why this occurs however.
09-29-2008, 09:29 AM
#5
Melting Slicks
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Wally,
When I install headers I always replace the spark plugs for just that reason, I just don't trust spark plugs that have been removed for $40 - $50 it's just not worth the hassle. A cracked electrode would definatly cause and issue like you had at Nats. I guess we'll see. Oh btw I have never seen a factory GM coil pack fail, I've seen an MSD coil pack fail but not a GM one yet.
Joel
When I install headers I always replace the spark plugs for just that reason, I just don't trust spark plugs that have been removed for $40 - $50 it's just not worth the hassle. A cracked electrode would definatly cause and issue like you had at Nats. I guess we'll see. Oh btw I have never seen a factory GM coil pack fail, I've seen an MSD coil pack fail but not a GM one yet.
Joel
