BrockB

Simple but ambiguous question:
What could cause wear in only one cylinder?

My cylinder 2 seems like its leaning out because the valves are more worn and have a whitish compound to them
what do you guys think?

the car is FI-mase kit/ E85/ ID2000s

TerminatioN

I'm no expert, but... Partially clogged injector maybe?

fernando.

^ + juan. My friend melted a piston is his car because he had faulty injector.

BrockB

good point, but it cant be that in my particular case because i recently had my injectors cleaned and they all are evenly flowing well according to the read outs. what else?

s2000ellier

Out of spec valve lash?

speedjunky01

Its a central cylinder, the pistons around it soak heat into it. Could tune it out I did on the turbo car just added 2 percent fuel enrichment to the two central cylinders since they always run a bit hotter.

mase1

What AFR are you running at full boost when this happened? if the injectors are flowing evenly, id advise to look over and run the engine richer and look at the timing curves as well. even factory valves should not be getting hurt like that. no point of running it leaner to make more power than whats safe!

BrockB

true... 12:1/12:0 when it was on the dynos but im taking a look at some street runs now at WOT full boost and its in the 13's some time.

damn, but then why only one cylinder, and not all of them?

street run (knock sensor bypassed)



dyno run

s2klariat

13.23 is a pretty aggressive tune but I wouldn't say it would be enough to cause that much damage. I'm thinking your issue is more centered on that particular cylinder. Faulty coilpack, spark plug gapped too wide, or possibly a fuel delivery issue. Check valve clearances as well. If everything checks out I say add a little fuel to that cylinder and ride on.

BrockB

The flow rate seemed to be relatively even for the injectors, especially since there's no distinction with the cylinder 2 injector.
I would think this eliminates the injectors being the cause.

I understand my tune may be way too lean on boost, and perhaps this may have something to do with it. But then why only one cylinder is being affected? For this reason, I am skeptical of this being the entire cause for it.

more info: leakdown test numbers were decent and relatively even across all cylinders. numbers were a little high but the engine was cold during the test. there was no particular valve leakage reported either.
pistons look good when the head was off.

so what else?