Knocking on acceleration
Thread Starter
6th Gear
Joined: Aug 2022
Posts: 6
Likes: 0
Knocking on acceleration
Bought an 02 coupe with 73000 miles last April and after a hundred miles or so began to hear a knocking/pinging on acceleration starting at ~1750 rpms and goes away when the rpm’s go back down. It doesn’t make this noise when revving at idle. It goes away or is barely noticeable after about 15 minutes or when the oil temp hits 190 or so. Took it to my mechanic and he said spark knock, said to keep running 93 gas through it and see what happens. I changed the plugs/wires and have been using a bottle of Techron every 3rd tank for ~2500 miles and the knocking is still present (possibly worse but that could just be paranoia). I attached a video, wish I could’ve gotten a better one but for whatever reason this is the only one that picked up the noise.
edit: can’t seem to attach the video, here is a link-
https://youtube.com/shorts/CNd94PReMy8?feature=share
edit: can’t seem to attach the video, here is a link-
https://youtube.com/shorts/CNd94PReMy8?feature=share
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
That video isn't of much help. If the engine is making noise you'll get more Intel and feedback if you record the engine running with the hood popped. Best of you have a camera person and someone else on the accelator so folks can hear variations at RPM.
Thread Starter
6th Gear
Joined: Aug 2022
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The issue is it sounds fine revving when parked. The noise only pops up when in gear driving.
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
Thread Starter
6th Gear
Joined: Aug 2022
Posts: 6
Likes: 0
Melting Slicks
Joined: Dec 2004
Posts: 2,847
Likes: 1,144
From: Sleepy Hollow- NJ
Thread Starter
6th Gear
Joined: Aug 2022
Posts: 6
Likes: 0
Took another video of it running with the hood popped for good measure, doubt it’ll be of any help though. This was a coldish start (other video was from this morning), any ticks you hear are gone in about five minutes.
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Thread Starter
6th Gear
Joined: Aug 2022
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Racer
Joined: Oct 2021
Posts: 324
Likes: 157
From: Maine
I have the same sound I think it's piston slap, or I hope it's piston slap. The sound gets much better when the oil temp is about 130ish.
When it get colder like 40 degrees in the morning it easy to hear. My car is also a 2002. I don't think badlifters or rockers get better when the oil temp goes up.
I have a local LS motor expert in town and plan on taking it to him to get his take on it. The sound bugs me but the car runs fine I just turn up the radio.
When I test drove the car a year ago they met me and the wife at a parking lot with a nice warm engine, if I would have heard the the knock I would have passed on it.
So far 6k with the sound and no problems yet. yet
I found some other youtube vids of piston slap in GM trucks the sound was a bit different but I think they iron blocks.
When it get colder like 40 degrees in the morning it easy to hear. My car is also a 2002. I don't think badlifters or rockers get better when the oil temp goes up.
I have a local LS motor expert in town and plan on taking it to him to get his take on it. The sound bugs me but the car runs fine I just turn up the radio.
When I test drove the car a year ago they met me and the wife at a parking lot with a nice warm engine, if I would have heard the the knock I would have passed on it.
So far 6k with the sound and no problems yet. yet
I found some other youtube vids of piston slap in GM trucks the sound was a bit different but I think they iron blocks.
Thread Starter
6th Gear
Joined: Aug 2022
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Yeah that knocking on the cold start I’d always assumed was piston slap and that goes away quickly enough I was never really worried about it. Even in that 2 minute video it’s quieted down a bit by the end. The knocking in the first video while driving is what’s started to concern me, wish it were easier to hear. Strange that it only happens in drive. It’s a different pitch and seems to be slowly taking longer to go away. I’m about 1000 miles from an oil change and plan on sending an oil sample to blackstone, we’ll see how that comes back.
Racer
Joined: Oct 2021
Posts: 324
Likes: 157
From: Maine
I am replacing my knock sensors Per the LS expert advice. I changed my Diff and during the test ride with the computer plugged in so he could make adjustments he heard some spark knock but did not see it on the laptop. I got a load of real bad gas during a trip far from home. One tank of shell 93 and it was gone. He told me it is common for the rear knock sensor to rust up and not work well and not through a code. Once I replace it he wants me to bring it back so he can check it out and I will ask he about what a normal LS1 should sound like. The first time he had the car I dropped if off the day before so he has heard it run from a cold start so I am hopeful my noise in just a cold morning bitch slap like when my alarm goes off to head to work.
Racer
Joined: Oct 2021
Posts: 389
Likes: 76
From: Chicago
I am replacing my knock sensors Per the LS expert advice. I changed my Diff and during the test ride with the computer plugged in so he could make adjustments he heard some spark knock but did not see it on the laptop. I got a load of real bad gas during a trip far from home. One tank of shell 93 and it was gone. He told me it is common for the rear knock sensor to rust up and not work well and not through a code. Once I replace it he wants me to bring it back so he can check it out and I will ask he about what a normal LS1 should sound like. The first time he had the car I dropped if off the day before so he has heard it run from a cold start so I am hopeful my noise in just a cold morning bitch slap like when my alarm goes off to head to work.
Racer
Joined: Oct 2021
Posts: 324
Likes: 157
From: Maine
True I had two knocks one is all fix by Shell 93 octane, during the test drive for my new diff about 10 miles of mixed driving with bad gas we heard the knock around 5000 RPM. He was checking my shift points 0-60 then wide open throttle downshifts at 31 mph for 2nd to 1st then 3-2 and 4-3 and at 5000 we could hear knock but the sensors saw nothing.
My car is an A4
My car is an A4