Timing issue
Thread Starter
Instructor
Joined: Dec 2005
Posts: 179
Likes: 0
Timing issue
I have an 88 with a 383 stroker motor that ran great till today. Now it seems to have a miss and the ignition timing will not advance when I plug or unplug the est wire. It stays right at 6. Any ideas???? I changed the coil, cap, rotor, plugs. I don't want to throw parts at it.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The timing signal comes from the pickup coil in the distributor and goes to the Ignition Control Module. From there it goes to the ECM, which does the advance calculations and sends the new signal back to the ICM. The ICM fires the coil.
When you disconnect the EST connector it breaks the connection from the ECM to the ICM and all the timing is done inside the ICM.
The connections between the ICM and the ECM go through the 4 wire cable that comes out of the back of the distributor. I suggest checking that cable for problems and try a replacement ICM if none are found.
When you disconnect the EST connector it breaks the connection from the ECM to the ICM and all the timing is done inside the ICM.
The connections between the ICM and the ECM go through the 4 wire cable that comes out of the back of the distributor. I suggest checking that cable for problems and try a replacement ICM if none are found.
Burning Brakes
Joined: Nov 2010
Posts: 1,006
Likes: 2
From: Spartanburg South Carolina
ICM will do it to ya everytime! had the same prob as well. I doubt you have a bad injector, the problem would be more noticeable than a slight miss at idle. May be dirty but I'm sure they're all firing. Could be timing is still slightly off, you still using oem stamped timing indicator and damper? Those things can be off by a few degrees and not even be able to tell
