So, I've been troubleshooting a no start/no crank issue all this weekend on my MT 1987 325i and I'm stumped. I've read novels worth of forum post looking for things to test, but as I said, I've run out of ideas.
I had no history of start issues before this. I had not performed any work on the car before this failure.
Things I've Tested:
Also, every electronic in the car appears to function properly when the key is in the ON position: windows, radio, lights, etc.
There is no dimming of the lights when I turn the ignition to the START position.
I've also run the ignition switch test in the Bentley Manual. Couple question about the Ignition Switch test that I've been unable to get an answer to, is... (1) When I performed the "Start only" test between C1 & C there was continuity when I first begin turning the key, but once I reach the full START position there is no longer continuity. Is this how it normally functions or should it maintain continuity? I've been looking at my cars wiring diagram and I can't figure out what C1 and C are for. The wires are BROWN and BROWN w/ LIGHT BLUE STRIPE.
(2) The starter signal wire receives 12V when the key is in the ON & START positions. Should it only receive 12V in the START position or is this working as intended?
From Bentley Manual, pg. 520
I had no history of start issues before this. I had not performed any work on the car before this failure.
Things I've Tested:
- Battery
- Original Starter and known working starter (tested both starters out of the car and they both function properly).
- Starter signal wire receives 12V
- Crankshaft Position Sensor
- Fuel Pump
- Relays
- Fuses
- ECU connector - passed all continuity, voltage, and ground tests
Also, every electronic in the car appears to function properly when the key is in the ON position: windows, radio, lights, etc.
There is no dimming of the lights when I turn the ignition to the START position.
I've also run the ignition switch test in the Bentley Manual. Couple question about the Ignition Switch test that I've been unable to get an answer to, is... (1) When I performed the "Start only" test between C1 & C there was continuity when I first begin turning the key, but once I reach the full START position there is no longer continuity. Is this how it normally functions or should it maintain continuity? I've been looking at my cars wiring diagram and I can't figure out what C1 and C are for. The wires are BROWN and BROWN w/ LIGHT BLUE STRIPE.
(2) The starter signal wire receives 12V when the key is in the ON & START positions. Should it only receive 12V in the START position or is this working as intended?
From Bentley Manual, pg. 520
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