just while the car is away for me - any reason for intermittent and random counts of knock, like 3-5, sometimes on spool? One pull it'll do it, could do one immediately right after with zero counts. Interestingly, the old engine did this, and after I popped that motor (likely oil starve or maybe fuel starve or some small line or any random thing) on track the new OEM shortblock motor does it too. Different tuners, etc. all encountered the same, random, inconsistent, and small counts of knock on both motors. Both cars made power in the range they were supposed to. spark plugs looked good.

I'm replacing the knock sensor, since that was likely a carryover. Also replacing the exhaust, at least the o2 housing and downpipe, and this DP has a flex on it too which may help since I think the old exhaust potentially introduced some rattle and at least some increase in back pressure due to being 2.75" before the rest of the exhaust went 3". I'm kinda suspecting one of those two things. I don't think it's engine damage since it's still a pretty new OEM block, plus the old block had the same issue. Happened on pump and E85 alike, which to me is another hint that it's not an actual motor problem.

 

I know that on my setup, it took some fiddling to get the downpipe to not hit on stuff. This was causing some random knock for me and after a few times loosening and moving the DP, I finally got it in a spot where it doesn't hit anything and haven't had an issue since.

One question I'd ask is does it do it at lower power levels aka not being run on the edge? If you limited the boost and timing and still saw the knock, it would certainly help point to some mechanical source.

 

hmm i'd have to ask the tuner. most of the power pulls are done at WOT but i'm not sure if they saw it on the partial throttle pulls or not. I do know that one pull they saw the knock, did another pull right after, theoretically should be hotter, and didn't see it. the new dp's got a flex pipe on it, that may help.

 

Are you running standard ignition coils, or aftermarket units?

 

denso coils from a spoolinup kit. this happened before and after the spoolinup.

 

It’s hard to find
My 8 had knocking and Ivey tune couldn’t find it.


it’s not easy to find!!

To diagnose car knocking, follow these steps:

1. Listen for the Sound: Pay attention to any unusual knocking or tapping sounds coming from the engine. The knocking noise is often rhythmic and can vary in intensity. It's typically more noticeable when the engine is under load or at higher RPMs.

2. Determine the Location: Try to identify the general area where the knocking sound is coming from. It could be from the engine compartment, bottom of the engine, or other components like the exhaust system.

3. Check Fuel Quality: Poor fuel quality, such as using lower octane fuel than recommended, can cause knocking. Make sure you're using the proper fuel grade as specified by the manufacturer.

4. Check Engine Oil: Inspect the engine oil level and condition. Low oil levels or dirty oil can lead to knocking. If the oil is overdue for a change, it's recommended to have it replaced.

5. Check Ignition Timing: Incorrect ignition timing can cause knocking. Consult the vehicle's manual or a professional to verify that the ignition timing is properly set.

6. Use Higher Octane Fuel: If your vehicle requires higher octane fuel, ensure that you're using the appropriate grade. Using lower octane fuel than recommended can lead to knocking.

7. Inspect Spark Plugs: Worn or damaged spark plugs can cause engine knocking. Check the condition of the spark plugs and replace them if necessary.

8. Check for Engine Overheating: Engine overheating can result in knocking. Verify that the cooling system is functioning properly, and ensure there are no coolant leaks or radiator blockages.

 

I'm not talking about partial throttle so much; although that would be interesting, I mean actually changing the tune to take out a bit of timing and boost.

The fact that you didn't see it on a pull right after you did points towards a mechanical source in my head. Exactly what you said, it was hotter and should have been worse.

 

for me, it was a bad/old knock sensor!

 

O yea, that will do it too lol. Glad you got it sorted out.