1990 Engine Timing Procedure

[Split63]

Hello,

What is the procedure for setting the timing on a 1990? Specifically, is there some wire I'm supposed to disconnect before adjusting the timing?

THanks,

UPDATE:
I just remembered I have a book on GM fuelinjection. In this book they describe three methods to set the timing.

1. Disconnect a tan and black wire (does not say where it is). This will set a code and turn on the check engine light, but will allow the timing to be set

2. Disconnect the wiring bundle to the distributor. This will set a code and turn on the check engine light, but will allow the timing to be set

3. Jumper pins A and B of the ALCL connector. This will not set a code.

Option 3 seems the best to me.....but will this work for a '90 vette?

 

[Hrtbeat1]

Timing

You have to disconnect the tan and black wire before adjusting the timing. If you look between the distributor and your ECM there should be a single wire with a simple connector. Disconnect this then adjust to the proper setting. Tighten down the distributor hold down then reconnect the tan/black wire.

The reason for disconnecting this wire is it has something to do with the computer tries to adjust the timing and by disconnecting this wire you can manually set the timing once set and the wire reconnected the computer picks back up where it left off. It still makes small adjustments as you drive.

Jumpering pins A and B will just display any fault codes stored in your computer. The check engine light flashes. This is with the key in the run position but the car NOT running.