Alternator rebuild.

[aston_jag_tech]

I wanted to share an issue with my less than efficient charging system...

Intermittently the "Bat" and "Park Brake" Illuminated at first start up and would shut off after I passed 3000RPM.

Intermittently the "Check Engine" illuminated and then shut off with no issues. This happened rarely at first but then more often closer to complete failure.

Intermittently the car stalled while in traffic. Happened once day before complete failure. Restarted with no issue. No warning lights.

Intermittently the "ABS" light came on. Exterior lights on. Audio Head Unit shut completely down and would not power up. "Check Engine" on and flashing(I counted a 21 code), turning the exterior lights off, "Check Engine" shut off and Audio Head Unit powered up.

Shut off car and accessories. Attempted to turn engine over, slow crank no start. Complete failure.

Diagnosis-
-Charged battery for 1 hour, test battery ok, passed at 12.54v. Started engine and checked charging output to battery at battery terminals-11.20v.
-Checked charging output at alternator 11.20v.
-Replaced alternator volt. reg.(included brushes)
-Continuity test of Stator-OK.
-Visual inspection of rotor-OK, contact points for brushes is worn.

Install-
Reinstalled, check output at alternator. 14.40v

Hope this helps anyone diagnosing electrical issues.

-Scott Garven

[Barney Paull-Edwards]

Good info! It comes back to the two most important gauges that BMW never fitted,an ammeter/voltmeter and a WATER pressure gauge.These wo will indicate 99% of problems that get posted.My pressure gauge told me instantly that my plastic pump was giving up,if only I had remembered to re-connect it to the top tank!

[Jon K]

there's a volt meter built into your OBC

[skr]

yea, i had those slip-rings totaly fail 300 km away from home. brushes have eaten away at those till they hit plastic. same simptoms, except i allso have the abs light on. i was realy thankfull for that 100 amp battery under the seat. it didn't start anymore when i got home, but i got there