TPI idle advance question
Thread Starter
Melting Slicks
Joined: Jan 2014
Posts: 2,192
Likes: 381
From: Lunenburg MA
TPI idle advance question
I'm working on resurrecting an '87 and I have a TPI question. I disconnected the EST cable and set the advance to 6 deg, but when I plug it back in, it's still 6 deg. Also my scan tool says it's 25 deg even though it's still at 6 (idle). I assume this isn't normal? It will advance as I raise the RPM.
It's recently rebuilt with new Bosch III injectors, but it idles like crap with low vacuum. Can't find any leaks with propane.
It's recently rebuilt with new Bosch III injectors, but it idles like crap with low vacuum. Can't find any leaks with propane.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The ignition module controls the spark until the ECM determines that the engine is running. Then the ECM puts the ignition module in bypass mode and takes over control of the advance.
Have your ignition module checked. Also look at the EST connector and the 4 wire harness coming out of the back of the distributor.
My ECM sets the advance to 20° at idle. Yours might be calibrated differently, so 25° seems reasonable.
Have your ignition module checked. Also look at the EST connector and the 4 wire harness coming out of the back of the distributor.
My ECM sets the advance to 20° at idle. Yours might be calibrated differently, so 25° seems reasonable.
Racer
Joined: Apr 2013
Posts: 435
Likes: 4
From: Guilford NY
I'm working on resurrecting an '87 and I have a TPI question. I disconnected the EST cable and set the advance to 6 deg, but when I plug it back in, it's still 6 deg. Also my scan tool says it's 25 deg even though it's still at 6 (idle). I assume this isn't normal? It will advance as I raise the RPM.
It's recently rebuilt with new Bosch III injectors, but it idles like crap with low vacuum. Can't find any leaks with propane.
It's recently rebuilt with new Bosch III injectors, but it idles like crap with low vacuum. Can't find any leaks with propane.
Thread Starter
Melting Slicks
Joined: Jan 2014
Posts: 2,192
Likes: 381
From: Lunenburg MA
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You'll get an error code 42 by disconnecting the EST connector. You can clear it or it will go away by itself after 50 restarts without errors...
Racer
Joined: Apr 2013
Posts: 435
Likes: 4
From: Guilford NY
Since I just timed my engine tonight, I have some insight here. I plugged the EST connector back in and the idle did not change, so apparently the ECM remembers that it is not controlling the spark. I shut off the engine and restarted it and it idled normally.
You'll get an error code 42 by disconnecting the EST connector. You can clear it or it will go away by itself after 50 restarts without errors...
You'll get an error code 42 by disconnecting the EST connector. You can clear it or it will go away by itself after 50 restarts without errors...
