Alternator check, Pre engine install checking for wiring issues Options

[Ishley]

I’m looking for input from electrical experts.

I’m preparing to install my rebuilt engine in my rebuilt 72. I was checking continuity in the harnesses and possible ground problems. The engine is out of the car… both the ignition and djet harness are all plugged to the proper end points but nothing is plugged into the car itself. I’ve gone thru every wire and connection… cleaned, fixed, shrink-wrapped and got it as good as I could.

I was double checking the starter and decided to buy a new one… as mine is pretty crusty and didn’t seem to work well before I pulled the engine. I bench tested it and the solenoid seems flaky.

I also purchased and installed a new alternator… 70 amp version… and I was just checking for the 10th time that all the wires had continuity back to the relay board
Plugs… and didn’t have any shorts to ground. It’s installed in the engine and the alternator harness is connected inside the alternator.

When I installed the new alternator… I was certain that the post in the back didn’t ground to the back cover… but now with everything mounted… the red wire that connects at the starter… seems to have a trace to ground when I go between it and the engine. Is this possible? It seems the diodes in the alternator would now allow anything to go to ground.

If I have to pull the alternator… I will… easier now before the engine is installed… but am
I missing something?

Thoughts?


Ed

[Superhawk996]

Deep dive it.

The B+ red wire from alternator should not be shorted to ground.

Figure it out before starting it.

[porschetub]

I’m looking for input from electrical experts.

I’m preparing to install my rebuilt engine in my rebuilt 72. I was checking continuity in the harnesses and possible ground problems. The engine is out of the car… both the ignition and djet harness are all plugged to the proper end points but nothing is plugged into the car itself. I’ve gone thru every wire and connection… cleaned, fixed, shrink-wrapped and got it as good as I could.

I was double checking the starter and decided to buy a new one… as mine is pretty crusty and didn’t seem to work well before I pulled the engine. I bench tested it and the solenoid seems flaky.

I also purchased and installed a new alternator… 70 amp version… and I was just checking for the 10th time that all the wires had continuity back to the relay board
Plugs… and didn’t have any shorts to ground. It’s installed in the engine and the alternator harness is connected inside the alternator.

When I installed the new alternator… I was certain that the post in the back didn’t ground to the back cover… but now with everything mounted… the red wire that connects at the starter… seems to have a trace to ground when I go between it and the engine. Is this possible? It seems the diodes in the alternator would now allow anything to go to ground.

If I have to pull the alternator… I will… easier now before the engine is installed… but am
I missing something?

Thoughts?


Ed

Appears the biggest issue folks have is the positive terminal post can be too close to the metal cooling duct cover ,this can be an issue with a rebuilt unit or new non OEM units , seriously worth checking as the end result is total melt down ,even on a stock unit the threaded post is fairly close or was on my last build .
If this is checked and ok it's just a matter of correctly wiring it with good clean connections you will be fine , cheers.

[Ishley]

I dropped the alternator and wiring harness. Pulled the harness all apart and replaced the big red wire. Cleaned all the connections and ends. Put new shrink wrap and covers around everything and reinstall it all. Everything checks out now with no shorts. I'm glad I double checked it before installing the engine. Waiting for a new starter now.

Onward and upward.... almost 2 years of daily work on this car. should finish right as driving season ends... I'll have all winter to work out the gremlins.