mass air flow
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
I have worked with a C4 that had a bad Knock sensor and I learned a little at the same time. My car was running terribly and was low on power and just felt like it was being held back when driving it. I replaced the knock sensor and the problem stopped. I later found out that my EGR was frozen and that helped my car run like poop as well. The knock sensor was over-active and the car suffered for it. The EGR was a project on it own merit. Once everything was fixed or
replaced the engine runs great, surprise.
I was surprised reading that the method of testing your knock sensor it to "Tap" on the engine block with a small hammer with the engine running and the engine idle should slow down as the Computer pulls back the timing. The problem here is that if you have an oversensitive Knock sensor or a noisy component that is making metallic noises your knock sensor might not be able to tell the difference. A noisy timing chain is able to trigger some knock sensors so it is important to get the right Knock sensor/s for your Corvette.
Modern C4's can actually isolate the cylinder that had the "knock" and retard just "that" cylinder instead like the L98 where the entire 8 cylinders get their timing pulled back. I wish I had the feature if retarding the individual cylinders when they knock.
replaced the engine runs great, surprise.
I was surprised reading that the method of testing your knock sensor it to "Tap" on the engine block with a small hammer with the engine running and the engine idle should slow down as the Computer pulls back the timing. The problem here is that if you have an oversensitive Knock sensor or a noisy component that is making metallic noises your knock sensor might not be able to tell the difference. A noisy timing chain is able to trigger some knock sensors so it is important to get the right Knock sensor/s for your Corvette.
Modern C4's can actually isolate the cylinder that had the "knock" and retard just "that" cylinder instead like the L98 where the entire 8 cylinders get their timing pulled back. I wish I had the feature if retarding the individual cylinders when they knock.
Team Owner
Joined: Jul 2004
Posts: 28,474
Likes: 3,291
From: Hartford WI
I was surprised reading that the method of testing your knock sensor it to "Tap" on the engine block with a small hammer with the engine running and the engine idle should slow down as the Computer pulls back the timing. The problem here is that if you have an oversensitive Knock sensor or a noisy component that is making metallic noises your knock sensor might not be able to tell the difference. A noisy timing chain is able to trigger some knock sensors so it is important to get the right Knock sensor/s for your Corvette.
Modern C4's can actually isolate the cylinder that had the "knock" and retard just "that" cylinder instead like the L98 where the entire 8 cylinders get their timing pulled back. I wish I had the feature if retarding the individual cylinders when they knock.
Modern C4's can actually isolate the cylinder that had the "knock" and retard just "that" cylinder instead like the L98 where the entire 8 cylinders get their timing pulled back. I wish I had the feature if retarding the individual cylinders when they knock.
Modern C4s can?
