I have an 85 pick up that the PO put a 22re out of a '92 4Runner. The wiring and ECU is all out original from the 85. The check engine doesn't come on immediately after it started (so it passes smog ) but does come on probably after about 5-10 minutes of driving, usually the first time RPM's go above 3k. I ran the diagnostic with my trusty scan tool and got error code 12, "Knock control sensor signal has not reached judgement level in succession."

The truck runs pretty good (besides rough starting but I think thats the fuel pump). My question is are the sensors from newer 22re's compatible with the older ECU's? I was just wondering if this is a known common issue, or if I should treat like a normal error and start looking at the wiring etc. Thanks in advance for your help!

 

I know that the injectors are different between the old and the new trucks. I had the same problem with my knock sensor on my new engine imediatley after rebuilding and reinstalling it last week. My problem was that the plug was not on the sensor correctly. Evidently it will slide on two different ways and only one is correct.