ever since i put the 383 and got into tuning my car, its had the problem where if the voltage on the battery is even a little bit low, i get no spark and the car wont start. verified by timing light, i've yet to check the injectors cause i cant find my noid lights. if i hook jumpers up to it it gets spark and fires right up, mind you the battery is not low or dead (12.5ish volts and 900ish cranking amps on tester), its fairly new and it has good cranking power when im having this issue, just no spark or start. is there a table i should be looking at to fix this issue? using SAJUP V4 8D

 

Shouldn't have anything to do with the ECM. During cranking the ignition is entirely under control of the distributor. To double check this open the EST/BYPASS connector the next start up. That will make sure that even if the ECM is bad the distributor is in complete control of the ignition.

The two wire pigtail between the coil & ICM bad be going bad. The wire likes to break inside of the insulation where it exits the coil end connector.

RBob.

 

Whats the voltage read when it's in the car? What does it read when you go to crank? I've seen batteries that "test" okay but really have gone bad. What condition are the battery cables in? They go bad as well building more resistance and the 12.5 volts may not be enough to travel though the cables. When you jump start it with another car, the battery is actually receiving 14.5 volts with a properly working alternator. Check the voltage down at the end of the cable attached to the starter, engine not running. If you have less than 12.5 this could be the issue.