Hey guys. I have been having a very interesting issue with knock detection on my car. Here is the issue as best that I can explain it.

When I start my car cold, there is no issues other than idle surge. as I drive my car it feels strong and runs great. This is until the car reaches operating temp. Then I seem to have a ton of knock detection even at just normal cruising speed in 5th gear at about 60-65 mph, randomly my check engine light comes one and I can feel a severe power loss. Now if I just drop to 3rd gear and floor it, I don't have a single issue. I am really confused and have no idea where to start. I do know where I have a couple small issues but they have never caused any issues in the past.

I do have ECMlink V3 lite.

Thanks in advance for the help.

AlaskanDsm said:

Hey guys. I have been having a very interesting issue with knock detection on my car. Here is the issue as best that I can explain it.

When I start my car cold, there is no issues other than idle surge. as I drive my car it feels strong and runs great. This is until the car reaches operating temp. Then I seem to have a ton of knock detection even at just normal cruising speed in 5th gear at about 60-65 mph, randomly my check engine light comes one and I can feel a severe power loss. Now if I just drop to 3rd gear and floor it, I don't have a single issue. I am really confused and have no idea where to start. I do know where I have a couple small issues but they have never caused any issues in the past.

I do have ECMlink V3 lite.

Thanks in advance for the help.

Click to expand...

What you have is a classic case of Phantom Knock(PK). It can be caused by a lot of issues and plagues 1g 6 bolt motors. It could be a bad knock sensor, under or over tightened. Could be lifter tick, solid motor mounts, exhause hitting something. Can be so many issues. I ran ecmlink full version and it has a feature that lets you turn off the knock sensor below a certain rpm and a certain throttle position. I would not activate the sensor till 200 rpms before full boost or over 75% throttle.

After awhile it became such an issue on my car that I deactivated the knock sensor and tuned without it. On e85 I was not that scared since it never knocked anyways. Good luck on finding the issue and fixing it.

Take a look at the back of the knock sensor for any black goo running out. This is the telltale sign of a failed knock sensor.

I am getting some phantom knock right now just cruising around too and I think we have narrowed it down to a lifter. I am changing them out this weekend to see if this will clean it up. I was getting 17 counts at 3k rpm and throttle at 25%. I used a mechanic stethoscope to just listen around. Amazing how much stuff you can hear. I am going to do this semi regular basis to get a feel for how things sound when they are correct and add that to my tools for diagnosis.

AlaskanDsm said:

I do have ECMlink V3 lite.

Click to expand...

Post a log. Lets see whats going on in there.

Thanks guys for the responses. my laptop motherboard fried on me a couple months back and I haven't had a chance to replace it yet. I will get ECMlink installed on a different computer and run a log for you guys. I was driving to work today and it was pretty bad. Right at about 60mph cruising, I have my stock boost sensor set to be a nice little tweaker with knock. Well the check engine light would come on and the boost needle (knock counter) would like max out at 14 on the gauge (which means nothing other than ####.. lots of knock). I would let off the gas and let it fall to zero, step on the gas and it would do the same thing all over again. If I am going 70, I ardly ever encounter this issue. It also occurs when I am shifting through the gears right at about 2500-3000rpm.

Anyways, I will get back to you guys with that log.