Detonation and knock sensor

[bbfourwinn]

I have posted previously about problems with '96 5.0l EFI volvo penta. Ended up it was a detonated piston. In the process of having engine replaced. My question is about the knock sensor. If the knock sensor is working will it always prevent the pre-ignition? When you feel the timing being retarded should you shut the engine down immediately? If you continue to run the engine with the timing retarded is it possible to cause damage?

Thanks in advance!

 

[Don S]

Re: Detonation and knock sensor

If the knock sensor is working will it always prevent the pre-ignition?

If it's working, it will always TRY to prevent it. But it can only do so much. There may be other problems.

 

[bbfourwinn]

Re: Detonation and knock sensor

Thanks Don. When the knock sensor retards the timing is it a smooth lose of power or does it cut out (like a fuel problem)? When it no longer senses the knock does it immediately go back to full power or is there a delay?

Sorry for all of the questions, just trying to prevent another hole in the piston!

 

[newport dave]

Re: Detonation and knock sensor

As Don said, the knock control system can only do so much, it can only retard the timing 5 degrees to be exact. You will not feel the knock retard kick in, and you won't feel it as it gradually reduces the retard as it no longer detects knock.

You really need to determine what caused the detonation, and I would suggest using a scan tool to monitor knock control system activity once you get the boat back on the water.

 

[bbfourwinn]

Re: Detonation and knock sensor

As Don said, the knock control system can only do so much, it can only retard the timing 5 degrees to be exact. You will not feel the knock retard kick in, and you won't feel it as it gradually reduces the retard as it no longer detects knock.

You really need to determine what caused the detonation, and I would suggest using a scan tool to monitor knock control system activity once you get the boat back on the water.

What type of scan tool and what does it do?

 

[kirali]

Re: Detonation and knock sensor

Knock sensor should also send the motor into SLOW mode correct?

 

[bomar76]

Re: Detonation and knock sensor

No.