sixOHfour

Is it possible to have knock sensor problems without triggering a CEL or code? it seems like the timing is retarding badly when accelerating and while cruising on the highway. I did the HG's and everything else including TPS, but did not replace the knock sensor; which I did spill coolant on haha.

Is it possible for a knock sensor to "partially" function?

MudHippy

Short answer = No. It would definitely throw a code. It's not possible to test it, so in order to know when it's malfunctioning there must be a way for the ECM to diagnose it's functionallity for you. Hence the codes.

However...

http://autoshop101.com/forms/h40.pdf

skoti89

do you think that chain rattle(loose timing chain could aslo cause this?

MudHippy

I'm no knock sensor expert, so I can't say for sure either way. I'd say it's plausible, that's the best I can offer.

James Woods

iTrader: (1)

I have heard of unbalanced driveshafts sending vibrations through the powertrain and up into the engine and causing the knock sensor to read it as a knock, so it is totally possible for a loose chain to replicate a knock.

blake.nemitz

not to mention a loose chain to throw valve timing outta whack

skoti89

wait...I thought the knock sensor was a detonation sensor. sensing when each cylinder was firing. or is it a knock sensor that senses the bad kind of engine knock? I just did a rebuild because I had a rod knock.

Team420

yes... it senses for knock ( more specifically a sound in a certain frequency range) so if there is something rattling around, causing sound in that specific frequency range, the KS will do what its supposed to do... retard timing. U can confirm this, by hooking up a timing light, watch the mark, then have a buddy bang on the motor with a hammer (dont go all hulk hogan on it) and watch the timing marks retard....

Oh... and no the sensor would not cause a "cel" in this case, as it is doing its job, which is to retard the timing in the event of a knock/detonation/pre-ignition/ping