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melted the tip of the spark plug (help)

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16K views 27 replies 10 participants last post by  tp88  
#1 ·
Well i know lean or pre ignition would cause this to happen, but it only happened to #8 spark plug, All the rest look fine.

I have a couple friends who think my return fuel setup is wrong and may have caused only number 8 to melt from not having fuel. The way its setup, I have the feed line comimg In on the rear of the drivers fuel rail, then crosses over the alternator into the front of the passenger fuel rail and exits out the rear fuel rail into my regulator. The regulator has a return line going back to the tank. Idle is 40psi.

What do you guys think?
 

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#9 ·
I still think it looks broke. Usually if the tip was burnt off, the center electrode would show some signs as well. Once the tip of an Autolite plug snapped like that while I was adjusting the gap. Something was defective with the plug itself, because I barely touched it when it happened.
 
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#12 ·
Looks like it melted to me! The #8 will be the hottest cylinder if you didn't
do the coolant mod. If you really think it the injector you can swap it with
another one to see if it happens to the other cylinder. I ran my fuel routing
for long time the way you have it without issues.
You can also pull a few degrees timing from the #8 and or put a colder plug
in that hole.
 
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#15 ·
Awesome thanks ill keep that in mind

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---------- Post added at 08:25 PM ---------- Previous post was at 08:17 PM ----------

cliffyk said:
Detonation, severe--what does the WOT AFR look like?

What values are in the Spark Borderline table, what is the Global Spark Adder set to?
Click to expand...
Wot is high 11s creeping to 12 right before 6000. Tuner still working on tune. .

Timing is at 12 degrees @wot
Made 583rwhp @14psi

Idk the answers to the other questions

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#14 ·
Detonation, severe--what does the WOT AFR look like?

What values are in the Spark Borderline table, what is the Global Spark Adder set to?
 
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#17 ·
Mine did the same thing on number 8....I wasnt happy about it. The dyno was acting up when the tuner was tuning it and we didnt get to fully dial it in. I. My opinion 12:1 is too lean. ..I would go 11:1 (thats what im gonna do for peace of mind). 12 degrees isnt a whole lot of timing but some extra fuel will help cool it down. Also the cooling mod will help number 8 (I need to look into that as well)
 
#19 ·
Run my lines the exact opposite of yours and have not had any problems.

Drop the AFR to a consistent 11.5, I would never trust 12.0 afr on a power adder car, my aggressive street n/a tune was a solid 12.1. After richening it up try leaning it out a bit in the midrange only, see if it picks up any power, if not drop afr back down. Then crank the timing up, 11* is nothing with adequate IAT's and good fuel.
 
#21 ·
Well guy's, I installed some new plugs and did some small short pulls. Car pulls strong but starts going lean so I get out of it around 5000rpm. On the way back I pulled into my drive way and did a rev to about 5500 (no load). I started to hear a tap. But it didnt follow my engine rpm, so I got out my stethoscope. The tapping was coming from my turbo.. fck.

Pulled the down pipe off, and saw one bent fin on the exhaust side. The next day I pulled the turbo off and this is what I found.
Looks like some slag from a weld broke off from the turbo pipes and got caught in the housing... I have no luck with this car..
 

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