Knock question

[kluke15]

First time driving in some real heat after adding my long tubes. I was noticing my knock gauge on the ngauge was back and forth between positive and negative knock. Never more than 3*+ so I’m not super worried but I was just curious is this due to the temp of incoming air that it’s pulling some timing? Everything seemed to drive fine except for the knock sensor reading positive with engine load. For reference it was about 105 outside. IAT was anywhere from 110-130 and CHT around 190. I just don’t know much about tuning stuff yet

Sponsored

 

[Grimace427]

Check for contact between the headers and the side of the engine compartment especially around the A/C lines on the passenger side.

 

[kluke15]

I don’t even have the ac bracket I took that out. Headers have been on for a couple months now with no issues no vibrations. I’ve gone over it 10+ times so I know it’s not hitting. but like I said first time in some real heat so I just wasn’t sure if that normally results in some pulled timing or if there is actually knock occurring.

 

[Joe 5.0]

Run a bottle of octane booster and then see if you're still showing positive knock. If you still have the knock after this, then bad gasoline isn't an issue.

Since the AC bracket isn't there, check to make sure everything is tightened down correctly on the exhaust.

 

[Jay-rod427]

Knock at wot, or partial throttle low rpm cruising around? Positive knock is 100% normal at light throttle low rpm occasions.

 

[Lonmon]

What Jay-rod said. If its at WOT then datalog it and ask your tuner about it. If its at partial throttle around town cruising it can be normal.

 

[Mustang_Lou]

I get it when I give it a bit of extra throttle but do not go WOT … seems normal.

 

[EFI]

Well considering your had IATs in the 110-130 range then it's definitely part the PCM pulling timing due to high IATs. The tune starts pulling timing at 100* unless the tuner changed that.

 

[Jay-rod427]

Well considering your had IATs in the 110-130 range then it's definitely part the PCM pulling timing due to high IATs. The tune starts pulling timing at 100* unless the tuner changed that.

But that wouldn't be pulled as knockr. It's already pulled from base timing at those temps.

Sponsored