Electrical Problem
Posted: Sun Feb 24, 2019 9:54 pm
So I have the first electrical problem with the E12 ('77 530i) and hope the collective wisdom here can help. I've searched the board and can't find a post for the same problem.
My starter got unreliable. It would work fine for a while and then not. The solenoid would click but the starter would not turn the engine. No paperwork of starter ever being replaced (85k orig miles), so I figured it was time and ordered an E34 starter. Installed it, same problem.
Took some readings with a multimeter and tried to troubleshoot per the a factory manual and Haynes manual. Before I could figure anything out, I decided to remove the battery hold-down and move the battery over a little bit, because the main power wire from the battery to starter was stretched a little bit due to the solenoid on the new starter being shorter. After moving the battery over, the new starter worked but the car wouldn't run. It will fire with the starter engaged but will not run at all. This was a new problem.
I then thought to check the fuel pump, so I put the car on the lift, turned the key and the fuel pump was quiet. Started getting ready to check the wiring to the fuel pump then smelled something coming from the engine bay. A wire to the coil was smoking! It was the wire connected to the same small post as the black/red wire to the starter. Per the wiring diagram, it's a "transparent" wire that becomes green and (best I can tell) goes to the 7-wire connector on the side of the fuse box. The wire fried so bad that the the insulation is completely gone for at least 2 feet from the coil.
After letting everything cool down for a few minutes, I turned the key back to "on" and the wire immediately started to heat up again. Unplugging the red/black wire from the starter fixed the hot wire problem. I was able to leave the key in the on position without the wire to the coil overheating.
Sorry for the long set up, so here are the questions.
1. The starter is an updated Bosch OEM for a newer M30, so I'm guessing the connections are the same. With the main battery power post at three o-clock, I connected the red/black wire to the smaller spade terminal at twelve o'clock and connected the black/yellow wire to the larger spade connector at six o'clock. The ground wire from the solenoid to the stater is at nine o'clock. Is this correct?
2. It seems like more than a coincidence that the starter worked and then there was a new electrical problem after I moved the battery over a little bit. I took the battery completely out and glanced at the wiring around the battery. Nothing obviously pinched, worn or grounded out. Any thoughts?
3. Any thoughts on why the wire to the coil would fry when the red/black wire is connected to the starter but not when it's disconnected?
4. Any other thoughts or ideas of what the problem(s) could be? Feel free to ask me questions for diagnosis.
All responses will be greatly appreciated!
Thanks, Cory
My starter got unreliable. It would work fine for a while and then not. The solenoid would click but the starter would not turn the engine. No paperwork of starter ever being replaced (85k orig miles), so I figured it was time and ordered an E34 starter. Installed it, same problem.
Took some readings with a multimeter and tried to troubleshoot per the a factory manual and Haynes manual. Before I could figure anything out, I decided to remove the battery hold-down and move the battery over a little bit, because the main power wire from the battery to starter was stretched a little bit due to the solenoid on the new starter being shorter. After moving the battery over, the new starter worked but the car wouldn't run. It will fire with the starter engaged but will not run at all. This was a new problem.
I then thought to check the fuel pump, so I put the car on the lift, turned the key and the fuel pump was quiet. Started getting ready to check the wiring to the fuel pump then smelled something coming from the engine bay. A wire to the coil was smoking! It was the wire connected to the same small post as the black/red wire to the starter. Per the wiring diagram, it's a "transparent" wire that becomes green and (best I can tell) goes to the 7-wire connector on the side of the fuse box. The wire fried so bad that the the insulation is completely gone for at least 2 feet from the coil.
After letting everything cool down for a few minutes, I turned the key back to "on" and the wire immediately started to heat up again. Unplugging the red/black wire from the starter fixed the hot wire problem. I was able to leave the key in the on position without the wire to the coil overheating.
Sorry for the long set up, so here are the questions.
1. The starter is an updated Bosch OEM for a newer M30, so I'm guessing the connections are the same. With the main battery power post at three o-clock, I connected the red/black wire to the smaller spade terminal at twelve o'clock and connected the black/yellow wire to the larger spade connector at six o'clock. The ground wire from the solenoid to the stater is at nine o'clock. Is this correct?
2. It seems like more than a coincidence that the starter worked and then there was a new electrical problem after I moved the battery over a little bit. I took the battery completely out and glanced at the wiring around the battery. Nothing obviously pinched, worn or grounded out. Any thoughts?
3. Any thoughts on why the wire to the coil would fry when the red/black wire is connected to the starter but not when it's disconnected?
4. Any other thoughts or ideas of what the problem(s) could be? Feel free to ask me questions for diagnosis.
All responses will be greatly appreciated!
Thanks, Cory