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Ever closed a spark plug gap with FI?

Old Feb 18, 2005 | 10:44 AM
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Default Ever closed a spark plug gap with FI?

I was playing with the Dodge STS kit ( over boost engine shutdown ) yesterday when all of a sudden I got an engine misfire. CEL came on for #3 cylinder. Shat my pants for awhile, it's my daily driver.
Anyway, changed the shorts and let it cool down. I yanked the #3 plugs ( yes plural, two plugs per cylinder on the 5.7L motor, one fires on the exhaust stroke for emission reduction ). BOTH plug tips were folded over on the electrode! No indication of contact on the tips, never lost oil pressure, and never heard any funny noises. Plugs even looked good, no metal deposits or lean/white readings on either. Re-gapped them and started her up, no more problems.
One item of note, the crankcase oil breather had spit out a small portion of oil, like it had built up a large amount of internal pressure and farted.
I have heard of N2O folks collapsing gaps but never in low boost ( 5 psi ) FI. Anyone else had this happen?
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Old Feb 18, 2005 | 04:59 PM
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Originally Posted by ktmrider
I was playing with the Dodge STS kit ( over boost engine shutdown ) yesterday when all of a sudden I got an engine misfire. CEL came on for #3 cylinder. Shat my pants for awhile, it's my daily driver.
Anyway, changed the shorts and let it cool down. I yanked the #3 plugs ( yes plural, two plugs per cylinder on the 5.7L motor, one fires on the exhaust stroke for emission reduction ). BOTH plug tips were folded over on the electrode! No indication of contact on the tips, never lost oil pressure, and never heard any funny noises. Plugs even looked good, no metal deposits or lean/white readings on either. Re-gapped them and started her up, no more problems.
One item of note, the crankcase oil breather had spit out a small portion of oil, like it had built up a large amount of internal pressure and farted.
I have heard of N2O folks collapsing gaps but never in low boost ( 5 psi ) FI. Anyone else had this happen?
Happened to me on the my old turbo V6 setup, I changed the plugs and everything was okay, eventually it happened again. And then the next time it happened I destroyed a piston. I'd be very cautious.
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Old Feb 18, 2005 | 05:06 PM
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so whats the fix? move to a colder plugh?
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Old Feb 18, 2005 | 07:36 PM
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Originally Posted by TTExpreSS
so whats the fix? move to a colder plugh?

yes...any ideas...
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Old Feb 18, 2005 | 09:46 PM
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You can try a colder plug but I think you'll find its lean.....since the ground strap bent in the bend of the ground strap from compression... timing is pretty close ,so I'd say almost for sure it wants fuel...I'm sure if you had a egt meter and monitered it ,you would see excessive temparatures from not enuff fuel....all that being said a colder plug will help but I dont think it will solve your problems.....
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Old Feb 19, 2005 | 08:45 PM
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Thx for the responses and suggestions everyone.
I am eventually going with a colder plug but they are hard to find for the 5.7L Dodge motor, plus I need 16 total. I guess compared to the cost of the kit it is minimal but changing out those center style plugs is a royal PITA. Hmmm, plugs or piston/cylinder damage....choice now looks easier!
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Old Feb 19, 2005 | 11:07 PM
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I can tell you this. This happend to me and I just changed the plugs, only cause I checked the compression and it still have decent pressure. But the next time I took it out it did it again. What had happened is ring land came apart closed the gap the first time. Then it come apart again after I replaced the plug. You can run with a messed up piston but only time will tell when it's gonna take a dump. Good luck.
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Old Feb 20, 2005 | 11:25 PM
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Originally Posted by Blue99Ws7
I can tell you this. This happend to me and I just changed the plugs, only cause I checked the compression and it still have decent pressure. But the next time I took it out it did it again. What had happened is ring land came apart closed the gap the first time. Then it come apart again after I replaced the plug. You can run with a messed up piston but only time will tell when it's gonna take a dump. Good luck.
That's my biggest fear. The 5.7L Dodge motor has very thin top ring lands ( for emission reasons ) and the early Paxton kits cracked a few pistons. I did replace them with colder plugs and ran it at the strip today ( 110 octane fuel ) and things were great. Only time will tell but we are looking to find some forged internals soon.
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Old Feb 21, 2005 | 07:39 PM
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Arent the dodge hemis speed density? how are you even tuning the thing? Any remote idea what the air fuel ratio is?
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Old Feb 21, 2005 | 08:20 PM
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Happened to my when I blew my number 5 pistion in my 4.8l. its no fun
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