Testing a PE PCM

[MIKE'SVO]

So, I have 2 PE PCMs and I want to make sure they are good. Anyway to test them as standalone? I no longer have a 85.5 or 86 so I can't do a swap. Anyway to swap it in a 84 just to make sure it is good?
thanks, Mike

[MikeFleming]

Not as difficult as it seems.

Swap it into the 84 (first disconnect the 3-wire connector to the boost control module) and see if it will run codes. That will verify the main chip and memory. should get 11-11 unless there's something wrong on the 84's sensors or wiring. Alternately create a sensor failure (like unplug the TPS) and verify it records the appropriate EEC code.

Next start the car. If it starts and high-idles this will verify the fuel pump driver, ISC driver and both injector drivers.

Lastly put a timing light on it. With throttle closed at idle it should read 25-30 BTDC. This verifies the ability of the EEC to process ignition timing events.

DO NOT attempt to drive it. It will be dangerously lean (under load) and the Ks signal will keep timing overly retartded, resulting in very high EGT values.

This will test 90% of the functionality.

Remove PE, re-install TE (or whatever it came with). Recommect the BCS.

[Raven855]

Mike, doesn't he need to disconnect the 2 wire connector to the Boost Control Module and the 2 wire connector to the Boost Control Solenoid as well?

[MikeFleming]

Mike, doesn't he need to disconnect the 2 wire connector to the Boost Control Module and the 2 wire connector to the Boost Control Solenoid as well? The EEC chats with the BCM via the 3-wire connector (fused ignition power, EEC Boost level output, chassis ground) and then the BCM chats with the BCS via a 2-wire connection.

Once the 3-wire connector to the BCM is disconnected, the BCM/BCS are totally isolated from the EEC and chassis.

[Raven855]

Thanks, didn't have any wiring in front of me to look at.


and then the BCM chats with the BCS
This just sounded funny! Like a conversation at my house.....

[MIKE'SVO]

Excellent! Thanks for the info.