I want to check the timing on my 86 LG4 Trans Am but everything I read to get the info says I must go off the emision decal under the hood. Unfortunatly that decale is long gone so I need some help.

1. what is the base timing for this engine?

2. I cant find the standard tan with black wire to disconect the computers control of timing,Is there one to disconect on this engine?Is it a diffrent color?

3. Can anyone take a pic of an LG4 emmision decale so I can see all the info on it?

Thanks guys

 

IIRC the factory spec base timing was 6° BTDC.

It doesn't use the tan wire like the FI motors do. Instead, you disconnect the 4-pin plug that comes from the back of the distributor, usually hangs down behind the driver's side head.

I would set the timing as described, and adjust it from there, until you find where the engine runs the best.

 

not to be a dick or anything but a LG4 isnt isnt a H.O engine, thats an L69

 

It doesn't matter. 6* base should be fine. If he hears knock he can go to 4*.

 

Not for the LG4... At least not the 85 cars. My underhood label shows 0 degrees base timing.

 

I've still got the underhood stickers. It says 0 degrees.

I found that (with a functioning EGR) 6 degrees was much better when the engine was still stock (with plugged EGR passages, I'd get part-throttle pinging under load).

Now, I'm running 10 degrees base, burning 85 octane gas (that's regular here) with no pinging problems whatsoever. Even went through "fast pass" emissions testing with it that way. Part of the reason I can get by with that much advance is altitude, but 6 degrees shouldn't be a problem at sea level.