How to set initial timing on L98??
Thread Starter
Burning Brakes
Joined: Dec 1999
Posts: 984
Likes: 154
From: Columbia MD
How to set initial timing on L98??
Title says it all. I just put my distributor back in and have no idea how to set the initial timing.
The service manual says only to disconect the ESC connector near the brake booster. That's not much to go on. What does the ESC connector look like?
Another book says I can jumper pins A & B at the ALDL connector. So which is it? :confused:
Does the engine have to be cold or hot when setting the timing?
Help!!!
The service manual says only to disconect the ESC connector near the brake booster. That's not much to go on. What does the ESC connector look like?
Another book says I can jumper pins A & B at the ALDL connector. So which is it? :confused:
Does the engine have to be cold or hot when setting the timing?
Help!!!
Burning Brakes
Joined: Feb 2003
Posts: 1,212
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From: OH
Re: How to set initial timing on L98?? (LWesthaver)
to set timing you want the engine warm. the EST connector is near the brake booster, just one wire with connector. Just disconnect it, it will set a code, you will need to reset it after your done.
Then its just a matter of hooking up a timing light, and adjusting the distrubutor as needed, then tightening the holddown bolt back up. I felt it necessary to remove some vacuum value (not sure which one) in order to get my distrubutor wrench to fit. Other then that was a 10 minute process.
Don't forget to reset the computer after your done, just pull power for about 10 seconds, will reset the computer.
Then its just a matter of hooking up a timing light, and adjusting the distrubutor as needed, then tightening the holddown bolt back up. I felt it necessary to remove some vacuum value (not sure which one) in order to get my distrubutor wrench to fit. Other then that was a 10 minute process.
Don't forget to reset the computer after your done, just pull power for about 10 seconds, will reset the computer.
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: How to set initial timing on L98?? (LWesthaver)
There is a connector in the blk/tan wire that comes out of a large harness below the brake booster. Open that connector before starting the engine to set base timing.
The reason for jumpering ALDL pins A & B (upper right pair) is to avoid the code 42 from starting the engine with the ESC connector open. Otherwise, after you have set base timing, shut down the engine and open the connector in the orange wire near the battery for 30 sec to reset the ECM.
Since the ESC connector is open when you set base timing it doesn't matter if the engine is warm or cold as the ECM cannot effect the readings.
The reason for jumpering ALDL pins A & B (upper right pair) is to avoid the code 42 from starting the engine with the ESC connector open. Otherwise, after you have set base timing, shut down the engine and open the connector in the orange wire near the battery for 30 sec to reset the ECM.
Since the ESC connector is open when you set base timing it doesn't matter if the engine is warm or cold as the ECM cannot effect the readings.
Thread Starter
Burning Brakes
Joined: Dec 1999
Posts: 984
Likes: 154
From: Columbia MD
Re: How to set initial timing on L98?? (rsafier)
I felt it necessary to remove some vacuum value (not sure which one) in order to get my distrubutor wrench to fit. Other then that was a 10 minute process.
Thread Starter
Burning Brakes
Joined: Dec 1999
Posts: 984
Likes: 154
From: Columbia MD
Re: How to set initial timing on L98?? (65Z01)
There is a connector in the blk/tan wire that comes out of a large harness below the brake booster. Open that connector before starting the engine to set base timing.
I'll have another look *below* the brake booster. Maybe the wire is hiding from me. If I still can't find it I think I may resort to the A&B jumper of the ALDL to force the ECM to let go of the spark advance.
Since the ESC connector is open when you set base timing it doesn't matter if the engine is warm or cold as the ECM cannot effect the readings.
What do you think?
Do you have a picture of that tan/black stripe wire and connector that shows its location?
Thanks for the info. :thumbs:
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: How to set initial timing on L98?? (LWesthaver)
Sorry but it's a tan/blk wire and it's located to the right of the brake booster, about half way down the side, on my L98. There isn't much wire on either side of the black connector so you may have to search a little.
When this connector is open the ECM cannot contorl engine timing.
When this connector is open the ECM cannot contorl engine timing.
