I was having issues with my engine knock light flashing whenever I got into boost. If I drove the car to redline and avoided spooling the turbo... no knock light. I made a few calls and I was told that the issue is more than likely spark plugs. I bought a fresh set of plugs yesterday.. installed them last night and viola no knock cell under boost. Car drove like a champ. Park the car. This morning on my way to work.. issue comes back. Knock cell only when I spool. In my mind I managed to foul the plugs after 3 third gear pulls. I just dont know how that is possible. Any help would be awesome.

 

I doubt its spark plugs. My car does that also. I believe it to be phantom knock since its never same load or rpm.

Have you tried pulling timing see if it changes?

 

you posted this in the evo x section, but anyways what do your AFR's look like?

 

because its an evo x.

AFRs are good. Like I said in the original post. I had this issue consistently before changing the plugs. I changed the plugs last night and all was right again. Then this morning it started back up again with the same issue.

 

my bad, I just looked at your "Drives" not your sig. If you think you fouled the plugs, just pull em out and take a look.

 

It was likely. Coinsidence that it went away after the plug change.

 

I will check after I get it home.

 

The plugs were due for changing.

 

I recently tuned a car with a 5858 turbo and built engine with FiC1650 that has some phantom knock as well but currently it's only tuned on 93 octane pump gas. Has it always done this since your engine was built or is it a recent thing?

Reducing timing didn't help and some pulls were perfectly clean while others had random spikes of knock out of nowhere despite moderate timing and low 11's AFR. Boost didn't matter and it behaved roughly the same with 20 psi wastegate pressure all the way up to 30 psi. Still made a healthy 520 whp/400 wtq on STM's mustang dyno @ 30 psi and 480 whp/360 wtq @ 26 psi with smooth power curves.

He was still using some older stock spark plugs so he is getting some 1 heat range colder plugs gapped down to the .020"-.022" range. I dialed out the phantom knock as best I could at 20 psi boost and muted the check engine light flashing below 150 load so that he didn't go crazy. It could just be a built engine thing but hard to tell.

 

Ended up being a improper wire gauge used to wire fuel pump.

 

That would indicate that the car was leaning out during spool and the extra fueling is now preventing knock. Likely adding more fuel in the tables would have done the same thing, or having the low to high voltage cutover kick in earlier.