So basically i was doing a pull ~60-100 and when i let off the throttle the car stalled right now. turned it back over and realized i couldnt hit any boost. thought it was a popped intercooler pipe. when i came to a complete stop, i realized it couldnt idle correctly. it had an issue just geting going. came home and scanned the car, got a random cylinder 1 misfire. so i checked all intercooler pipes and checked the plugs. this is what i got:




Now im wondering how this happened, and wondering if it could happen again.
i swapped the plug out already with a temp hks plug. i have new NGK's coming in in the next couple days. should i be worried that this would happen again? when im WOT my air/fuel is 11.4-11.7.

The fuel is not an issue. I've been fooling my gas at the same gas station for the last 2.5 years, I always make sure it's Exxon 93, and that's the same gas I got tuned on. If I do fill up somewhere else, I never get in the car until I ive filed up the car 2 times and I know that the gas its still not in the tank.

 

Looks like you detonated to me. Hard detonation can close the spark plug gap. How much boost were you running and at what rpm did it happen?

 

I had a similar issue. Swapped plugs, and havent had a single issue since. I would say its a result of poor quality fuel(it happens sometimes)

If you do have it happen again I would suggest speaking to your tuner because I heard it could be results of an aggressive tune. But, again that is only something I read on here so it may or may not be true but sounds theoretically legitimate.

 

That is not good. Last time I saw this happen to my car, it was a result of detonation from a poor previous tune. It happened twice more before I realized what the root cause was, and that 3rd time was the end of my motor. You may want to bring your car to a reputable tuner and have the tune looked at.

 

Check your tune. How much boost are you running?

 

https://www.evolutionm.net/forums/ev...-failures.html

 

tuning is more than AFR's at WOT. Something is wrong...who did the tune? What boost controller are you using?

 

This provides all the info you need in my opinion. The exact same problem I had is what kracka had(Sleeve falling over electrode). And I agree with him 100% when he said that he believed a lot of it could have been caused by NGK poor quality control. I only say this because I had the same problem shortly after installing new NGK(non mitsu) plugs, replaced it with a new plug of the same type and havent had a single issue since.

So I would agree with the assessment that it is likely caused by NGK. Thank you Kracka for the great refference.

 

You are welcome. I also have a theory that bouncing off the rev-limiter is accelerating the problem; many of the failures I've seen have occurred shortly after sitting on the rev-limiter.

 

Bouncing off the rev limiter could do it too.

 

my tune is set for 26-27lb of boost. and i would say this happened by ~7500rpm

im running 26-27lbs.

Im tuned by JR one of the more respected tuners in my area. i did speak to him and he wants to do some logs once i get in my new plugs.

I dont sit on the rev limiter, ive done it a few times by accident but never intentionally. my rev limiter is set to 7800. i have a tendency of shifting at ~7500 i try not to bring it up that high. and im speaking in terms of spirited driving which isnt that often maybe once every ~300 miles if that. i commute a lot and i try to get top MPG as i can, so if i know im 20+ ill do a quick pull to ~120 and back off it for a few days.


i will check out the spark plug failure thread, but when i did do a search it seemed like it was a pretty common issue even on stock evo's.

 

Hitting my limiter once accidentally is what caused my plug to fail

 

what boost controller are you using?

 

does 2 step count as hitting rev limiter? If so then launching the car using 2 step will kill the plug?

 

Yes that counts...and it's possible. If you do that frequently I just recommend changing out your plugs more often.