When setting the timing for an lg4 do you have to disconnect any wires? I know for fuel injected models you have to unplug the tan wire but was unsure for carb'd ones.

 

Unplug the flat 4-wire connector that goes from the distributor base to the wiring harness loom on the firewall.

SES light will come on and set a trouble code. After reconnecting disconnect the ECM power wire for ten seconds (engine not running) to clear the code.

 

Got it thanks

 

Hey what about for a 1990 3.1L V6? Chilton says to disable EST, jump the AB terminals in the diagnostic terminal, and if that doesn't disable it, disconnect the EST bypass. But it doesn't say where it is. I know where it is on my 91 5.7L TPI, but there doesn't appear to be anything like that on this motor. I don't think is was disabled because the timing stayed a like 20 and it is supposed to be 10 according to Chilton again.

also the holddown bolt on the distributor appears to be larger than 9/16 so my 9/16 distributor wrench wont work. The guy at the Autoparts place said it is probable 15mm. Is this possible? Of course no one around here has a 15mm distributor wrench. I know the bolts for the coil bracket are 15MM.

Thanks for any help

 

Larry, you'd probably be best served inquiring on the V6 forum.

15mm wouldn't surprise me. You have a wire welder, of course, so you know what you need to do...

 

Larry- yes, it's 15mm and just about impossible to get without the proper distributor wrench. I bought mine from MAC Tools many years ago and the little 2.8/3.1 V6 appears to be the only engine in the world that uses that size distributor hold-down bolt.

Also, yes, you can just jumper the A&B terminals on the ALDL connector and it'll take out all computer supplied timing advance so you can set the base timing correctly. If memory serves, it's upposed to be 10* BTDC factory setting. I had mine up at 14* for a smidge more power but I had to use at least 89 octane to stay out of detonation with it that far up.