ECM, Timing, Dwell???
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 855
Likes: 0
I have three questions so here they are:
1. With the EST bypass connected what is the normal timing advance range (mine goes up to 48-50 degrees at 2000RPM)
2. The EST wire (white wire going to ignition module) carries the signal from the ECM, What is normal range for dwell.
3. Is my car getting too much advance?
Base timing was set with EST bypass wire disconnected. EST bypass wire (tan/blk) is getting 5 volts from ECM. With the EST bypass connected and at idle timing jumps all over the place. No codes stored.
TIA
1. With the EST bypass connected what is the normal timing advance range (mine goes up to 48-50 degrees at 2000RPM)
2. The EST wire (white wire going to ignition module) carries the signal from the ECM, What is normal range for dwell.
3. Is my car getting too much advance?
Base timing was set with EST bypass wire disconnected. EST bypass wire (tan/blk) is getting 5 volts from ECM. With the EST bypass connected and at idle timing jumps all over the place. No codes stored.
TIA
Burning Brakes
Joined: May 1999
Posts: 760
Likes: 1
From: Greenwich, CT
1. Not sure about an '86, but my '91 has 5 or 6 different tables in the ECM that control spark advance in various situations - if you invest in a copy of "TunerCat" software you can look at them graphically on your computer screen.
2. GM stock ECM chip has some really wild part throttle spark advance numbers - I believe they were done that way for drivability and fuel economy. Some in mine were as high as 40 deg, so your numbers aren't surprising.
HTH
DrJ
