engine timing
Thread Starter
Burning Brakes
Joined: Jul 2000
Posts: 1,045
Likes: 3
engine timing
I have my timing set at 6 degree advance on a L-89 TPI. Auto X-ray shows 40 degrees advance at 3800 rpm. Does the ecm electronicly advance the timing or is there something in the distributor that advances it. The metal cover over the star shaped piece under the rotor has some movement in it. Is that normal or should it be stable. I am running hot at highway speed and am wondering if I am acually getting the advance it needs....
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
The ECM controls dynamic timing off the base timing value according to engine parameters and stored tables.
Use Monitor Mode and see how much timing advance you get during a WOT run through the 1-2 shift. I expect you will see around 36-38deg.
Use Monitor Mode and see how much timing advance you get during a WOT run through the 1-2 shift. I expect you will see around 36-38deg.
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Originally Posted by toyvet1
I have my timing set at 6 degree advance on a L-89 TPI. Auto X-ray shows 40 degrees advance at 3800 rpm. Does the ecm electronicly advance the timing or is there something in the distributor that advances it. The metal cover over the star shaped piece under the rotor has some movement in it. Is that normal or should it be stable. I am running hot at highway speed and am wondering if I am acually getting the advance it needs....
You have the base timing (you can see it only with a timing light and the connector near the brake booster disconnected) set at 6 deg.
This is good because if the main spark table in your chip say that at a certain rpm level and at a certain load level the timing should be 40 deg, the ECM will add 34 deg.
If your base timing is 10 deg (your untouched chip has always 6 deg) and at the same rpm/load the chip table has 40 ) the ECM will ad always 34 deg ending a total time with 44 deg.
Your scan tool will report allways 40 deg
I'm pretty positive on all I said, but the last thing about what the scan tool will say...
If some experieced guru can chime in ...
-Beppe-
