Melted plug...
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Joined: Aug 2004
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From: Tyler, TX.
Melted plug... This is the only plug that melted and all the other plugs look just like the other one in the picture. It's on a 175 shot with TR6's. Does this look like a defected plug or is there a problem? A/F looks good all the way across except for an initial lean spike off. These plugs have quite a few miles after the runs and not just pulled after the pass.
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Joined: Oct 2005
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From: olympia, wash
Weird.
If your running a wet shot maybe your hitting that one cylinder a little heavy compared to the rest.
I have heard that with a wet system that the mixture has trouble evenly dispersing when just using a nozzle. Looks like the cylinder that had that plug was carrying more then its share.
If your running a wet shot maybe your hitting that one cylinder a little heavy compared to the rest.
I have heard that with a wet system that the mixture has trouble evenly dispersing when just using a nozzle. Looks like the cylinder that had that plug was carrying more then its share.
did you detect the lean spike while logging off the pcm, or wideband on a dyno?
if you were logging the pcm, how much knock were you getting?
electrode is a little melted - doesn't look like a defective plug.
if you were logging the pcm, how much knock were you getting?
electrode is a little melted - doesn't look like a defective plug.
Thread Starter
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Joined: Aug 2004
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From: Tyler, TX.
A/F was 11.2. It came out of cylinder 5 and im running a ls6 intake with a NX shark nozzle. Think timing is too high? Its at 21 right now. 
The lean spike was off the dyno. And i did get a knock retard of 4 right off the line on a HPTuners log at the track where this plug melted. I dont understand how to add fuel to a wet system for just the initial hit though?
The lean spike was off the dyno. And i did get a knock retard of 4 right off the line on a HPTuners log at the track where this plug melted. I dont understand how to add fuel to a wet system for just the initial hit though?
Last edited by 01'WS6; Nov 4, 2007 at 05:04 PM.
That cylinder is not the usual one to burn on nitrous. You have plenty of A/F and the timing is fine. Could have happened even when you weren't on the nitrous - maybe a dirty injector on that cylinder or an air leak on the intake causing that cylinder to go lean. I would pull the intake and check the o-ring and get the injectors cleaned and flow tested to try to get to the bottom of it. Also, is it possible that you are pushing the injectors too hard and that one gave out first? Do you know your duty cycle under WOT load?
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Thread Starter
TECH Regular
Joined: Aug 2004
Posts: 443
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From: Tyler, TX.
That cylinder is not the usual one to burn on nitrous. You have plenty of A/F and the timing is fine. Could have happened even when you weren't on the nitrous - maybe a dirty injector on that cylinder or an air leak on the intake causing that cylinder to go lean. I would pull the intake and check the o-ring and get the injectors cleaned and flow tested to try to get to the bottom of it. Also, is it possible that you are pushing the injectors too hard and that one gave out first? Do you know your duty cycle under WOT load?
P.S.- The car has a 233/239 cam with stock 241 heads and ls6 intake.
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The lean spike may just be the catalyst that starts the whole detonation issue and with the high temps, melted plugs? Try shorting your fuel to nozzle line as short as possible, this helps some with the lean spike.
Robert
Robert
Sounds like you need to work on the tune some more. If it is right, there shouldn't be a difference from open to closed loop.
Like Robert said, you can run a longer nitrous line from the solenoid to the jet, and a shorter fuel line to help with the lean spike. You can also richen it up some in the tune in the areas where the nitrous comes in...
Like Robert said, you can run a longer nitrous line from the solenoid to the jet, and a shorter fuel line to help with the lean spike. You can also richen it up some in the tune in the areas where the nitrous comes in...