Should have added, the distributor and Ignition Module were replaced when the rebuilt engine was installed. It is from CarQuest and just found out it was made in China.
Would the failure of the Ignition Module result in the engine not even cranking?
Vehicle: 1991 GMC Sierra 5.7L, 4000 miles on rebuilt engine, stock ignition system
As some of you may remember, my problem started off as being the Engine Service Light remained constantly lit. There were no error codes to be read (Or so I thought.) Managed to reset the system and the light remained off until the next test drive.
The light came back on and remained on. Found an owner's manual for the code reader and I had not been using it correctly. Was now able to read a Code 42, Electronic spark timing circuit - open or shorted.
Rerouted spark plug wires to insure no electrical interference. Checked connections, and continuity of the 423 EST wire, 424 By-pass wire coming from the Ignition Module going to the ECM. Also checked for possible shorts. Everything appears to be good, physically.
Following a trouble shooting flow chart, disconnected the ECM connectors. Turned the ignition on.
Probed the ECM harness connector CKT 423 with an Ohmmeter to ground. It should read less than 500 Ohms. It did at 356 but fluctuated with each try, though remaining below 500. The last try gave a reading of 0 Ohms, that I do not understand, but could be due to my inexperience/lack of ability.
Next probed ECM harness connector CKT 424 with a test light. The light remained off. No electrical current.
Following the flow chart, the next step was to connect the Ohmmeter to ECM harness CKT 423 and ground. Again probe ECM harness CKT 424 with the test light connected to 12 Volts. As the test light contacts CKT 424 the resistance should switch from under 500 to over 5000 Ohms. Resistance should have gone high (open circuit). It did NOT. IIRC, it remained at 0.
The flow chart stated this means:
CKT 424 open, faulty connections or faulty Ignition Module. (Wire has continuity, connections feel solid.)
CKT 423 shorted to ground. (Wire has continuity, does not appear to be shorted.)
Faulty Ignition Module?? When last test driven for 30 minutes, the engine did not exhibit any of the classic symptoms. It did not overheat. The engine started easily. The engine ran smoothly while being driven, but may have had a barely noticeable miss at idle.
Now it gets even better.
About one week later, when the weather improved (It wasn't snowing and the temperature was above 0 degrees F.), decided to do a retest.
The battery was dead! Something drained it. I believe it to be the small light in the glove box remaining on, when I left the door open after working on the wires going to the ECM. Maybe?
Ok, charged the battery and started over this morning.
Turning the ignition key to start, the console trouble lights came on as they should, but the starter motor did not/would not crank the engine. No clicking of the solenoid and the battery shows 12.94 Volts.
In addition, the code reader now shows a Code 34 (possible MAF sensor/MAP sensor problem) and then the original Code 42.
So now, on top of everything the engine will not even start.
Please, what do I do next?
Your assistance in this matter is greatly appreciated.