Hey guys

So I'm curious to see if anyone here has any good ideas..

Last night, for the first time in 25k miles since installing this motor, i noticed the power FC registered knock above 60 during free rev (clutch pushed in) in the higher RPM. It has never registered any knock during free rev before and doesnt make a lot of sense to me as to why it might be doing this as the engine is not under boost and has low load. The engine is not making any new noises and operates normal under low to medium boost.. It seems to be a high RPM problem.

Maybe unrelated, but it also is showing a tendency to knock in full boost (over 60) and feel a little sluggish up top.

Could bad gas cause knock in free rev high rpm?

What about oil seepage into the combustion chamber?

Maybe a dying cam sensor might cause preignition? Im not familiar with symptoms of CAS failure..

Im leaning towards bad fuel mixture or electrical problem more than a mechanical problem..

What do you guys think? Btw, this is a speed density car.

Could be bad gas like you said and also fuel filter or faulty knock sensors.

Fuel filter just crossed my mind as well.. I'll probably change spark plugs, just for eliminations sake and probably the filter as well..

I might even go as far as putting some race gas in to see if that helps or not..

It just seems a little baffling.. And obviously Im not going to bounce it off the rev limiter to see if i can recreate the problem because if it is something serious, i want to catch it early. Like the HIV.. gotta catch it early..

So I found a couple issues-

An injector oring was failing and allowing too much fuel into the cylinder. (Side feed injectors)

Also, the ground for the coil harness was not the best, creating a weak spark.

It was rich knock.

nice find.

xracerx972 wrote: ↑

Sun Sep 24, 2017 1:02 pm

So I found a couple issues-

An injector oring was failing and allowing too much fuel into the cylinder. (Side feed injectors)

Also, the ground for the coil harness was not the best, creating a weak spark.

It was rich knock.

So did that fix the knock completely? Or was that only part of the causes to the issue?