So, I found out that the truck is currently running a 89 4runner ECU on a 85 Celica engine.... and I was wondering if the wrong ECU for the injectors could be the cause of the knocking sound it does while idling. Actually, the engine always knock, the only time it doesn't is when I release the gas pedal and just let it cruise.

Oh.. and the knock gets quieter at higher rpm too!

Thanks for help!

Chocochat

 

tough to diagnose but sounds like a serious mechanical soon to be failure.

unless your talking about it knocking as in pinging as in marbles in tin can as in pre-detonating in which case i would check the timing.

 

^ x2

Can you post up a video of it knocking? The ECU shouldn't cause any problems.