Hi:

I have a 1993 Geo Tracker  - 150,000 miles on it and I drove it to work today and when I got back in it, the engine would turn over but I have chattering at the ignition relay (inside the cab), and the ISC (idle air control vavle), as well as the the EGR and Throttle position VSV's are chattering out in the engine compartment.  When I unplug the ISC, the chattering goes away but I still don't have any ignition.


I have 12.5v from the battery when idle and when I am cranking I am getting 11.5v

I have spark in my plugs and my fuel pump is priming.


I am at a loss as to what is causing the issues.


Thanks

Sounds like ECM.
Drop it down and take a look to see if there are any capacitors leaking. You can also check to see whether or not it might have been repaired prior.

sent from an anus from an asus

Update:


I took a wire and jumpered across the IAC wiring harness and it fired right up.  I put everything back the way it was and now it is running no problem.

Maybe something got stuck on the ECM or a relay got stock open.

I have 12.5v from the battery when idle and when I am cranking I am getting 11.5v

You should have approx. 14 volts at idle when all loads are turned off.