what do you think happened? sr20det torn down

[joe3180]

http://farm9.staticflickr.com/8535/8771410107_2212605e43.jpg

What are you thoughts on what caused this?

Im just happy the cylinder wall wasn't too bad.

s13 sr20det #4 piston everything else a-ok besides the piston bits in the oil pan.

New pic...
http://farm9.staticflickr.com/8546/8773710205_1f7cc148db.jpg

[joe3180]

first thoughts are leaky injector...

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Extremely lean on that cyl.

[joe3180]

Really...you think so? I would have thought if that were the case the piston would have melted more toward the center or at least more than it did, instead of just that little area.

[oni jake]

We've done the same thing just last summer. Never did figure out %100 what caused it. If its not a mechanical failure, such as a leaky injector, the blame is in the tune.
https://sphotos-a.xx.fbcdn.net/hphotos-ash4/422350_249058935197789_1613311140_n.jpg

We rebuilt afterwards and the entire gallery is here: https://www.facebook.com/media/set/?set=a.248729961897353.35214.132827516820932&type=3

[cotbu]

That piston should be the zilvia.net official troll face!

[ShadowMan]

Judging by the one picture, that piston looks pretty light grey/whiteish on top, which would lead me to believe you leaned out on that cylinder. #4 cylinders seem to be pretty notorious for running hotter than the others. Same thing happened to me, shitty tune is to blame for sure, at least in my case. I'm by no means saying it isn't a leaky injector, but I would imagine it would be blacker if that was the case. I'm also not a pro engine builder either, so there's that. Might as well check the injector and the tune.

[joe3180]

in person the top is fairly black with a crust of burnt oil. I think the flash just made it much lighter than it really is. Ill put up another picture of it later tonight where the flash isn't bleaching it out.

[steve shadows]

It's usually a shotty wiring harness where that injector driver is cutting out intermittently. Good wiring and good contact on all pins to outputs and inputs on sensors and drivers is the most important thing next to the actual tune on the car.

[joe3180]

thanks for the input. Well good thing I got a new wiring harness since this happened so if it was that, it wont happen again or shouldn't.