CODE 53 issues

So my 91 AT is throwing code 53 for the last couple weeks...

I purchased another ecu from DarthRipley (Thank You!) and let it run in the car, but the issue came back.

I also tried my JDM ecu with the same result.

According to the BGB CODE 53 is a fault in the knock control circuit in the ecu itself. Hence why I purchased and installed another one that was known to be good.

It simply is not possible that all 3 ecu's are bad.

I have also checked the wiring with my dvom and everything appears to be fine.

Any thoughts or suggestions?

I'm a bit stumped, as CODE 52 is able to detect a wiring fault or bad knock sensor, but it is only triggering CODE 53.

Your help is appreciated.

- Mario

i had a similar issue you might try to re-wire the knock sensor. i did this and it stopped the code 53(i had both 52 & 53) you do have to use shielded wire you can get it at radio shack and at most sterio shops.