Wednesday, July 20, 2011

In the Garage - E30 not charging? Check this first...

Shortly after putting the motor in the E30 and driving it home, I noticed my lights going dim, then really bright, then dim, then off. I switched off the ignition and the charge light was off on re-key. I had recognized this symptom and did exactly what I had done in the past - order a voltage regulator - durrh. The price is wrong, Bob...

This was my first mistake - not checking out the alternator itself before ordering the regulator. For some reason, BMW elected to choose two suppliers for alternators: Valeo and Bosch. I suspect that there was a Valeo alternator lottery and if a single digit prime number was drawn from 100 balls, then a Valeo was thrown at the car. All 96 other cars would get the ubiquitous Bosch alternator. The same ubiquitous Bosch regulator for which I bought a $25 regulator. Whatever, no biggie, changes are I'll need it on my next E30.

What struck me as odd was that the car was charging intermittently after doing the engine swap. I got a wild hair and tried grounding a jumper cable to the alternator and immediately after a shower of sparks, the lights came back bright. Switching the car off and re-keying showed the charge light coming on also. My prediction - since the car had no ground strap to the alternator previously and I did re-bush the alternator brackets, it must have been grounding through the mounts where the rubber isolators had worn away. I went and bought what they call a 'starter cable' from the parts house and grounded the alternator bracket to the intake manifold. Problem solved.

So next time your E30 isn't charging - before throwing a voltage regulator or heaven forbid an alternator at the problem - just try grounding the case (not the back!!) and see what happens.

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