924Board.org

Guest · Posted: Fri May 25, 2001 4:37 pm Post subject:

From: Jim Short
Email: jshort75@qwest.net
Date: 25 May 2001
Time: 16:37:22

Guys!!
I'm not reaching 12 volts while running. It should be charging over 12 volts while I'm running. The way it is I'm hanging at around 10V with little variation. If I turn on any accessories it drops way low. The head lights are dim and take some time to get to full brightness. Is the alternator just dirty? Can I take it off and inspect the wiring and brushes etc.. . . ? If not where can I get a cheap replacement alternator??

Guest · Posted: Fri May 25, 2001 8:12 pm Post subject:

From: leon
Email: leonl@xsite.net.au
Date: 25 May 2001
Time: 20:12:25

I have same problem. Is this alternator Porche only or is there a VW replacement. If I sit on 4000 rpm 130km/hr it starts charging , the gauge comes up into the green. Is the alternator suposed to kick in at 2000rpm like others?

Guest · Posted: Fri May 25, 2001 8:46 pm Post subject:

From: JoeD.
Email: 924 999
Date: 25 May 2001
Time: 20:46:13

Wow your 924 goes up to 4000rpm must be a diff.

po -rsche.

Guest · Posted: Sat May 26, 2001 5:25 pm Post subject:

From: Bill Reeve
Email: bill@ff.com
Date: 26 May 2001
Time: 17:25:41

Its down to belt they are always coming loose and often dont squeak you just get a drop in voltage best fix is to roughen the pulleys and get a wider belt like an EBC (uk) this sorted my problems.

Guest · Posted: Thu May 31, 2001 5:58 pm Post subject:

From: dave2
Email: david.c.russell@lmco.com
Date: 31 May 2001
Time: 17:58:00

First off, a voltmeter cannot be wired in serial with anything. Ampmeters can be wired in serial, voltmeters must be wired in parallel. Also, a voltmeter does not "see" power. Power is a measurement of the heat expended, usually in watts. Voltage is the measurement of potential energy, in volts. That being said, your alternator should be putting out between 13.5 and 14.5 volts under normal operating conditions. You have two possible conditions, either your volt meter is not reading the correct voltage, or your alternator is not putting out enough voltage. You can isolate the problem by using a multi-meter to read the voltage across the two battery posts. If it is the same low voltage that your in dash voltmeter is reading, the problem is with the alternator. It may be as simple as a bad ground, or slipping belt. Simply cleaning the grease off will not cure the problem. However, a low voltage reading in the ten volt range is usually caused by on on the diode rectifiers in the alternator being open (not functioning). If you have the alternator checked by a mechanic, or in a parts house, they may diagnose this as a shorted diode, but it is not a short, it is an open. My bet is that that is your problem. This is a common problem with Bosch alternators. You will have to replace the alternator to cure this problem. It is not a "Porsche" alternator. Therefore finding one from a VW, Audi, BMW or Mercedes will not change the price. If you want it to fit the same, you will need the same model Bosch that is currently installed in your 924. I replaced the stock Bosch unit in my '80 931 with a Delco (GM) unit from a '86 Camero in 1987, and have never had another problem. It cost me $25.00 back then, and has a lifetime guarantee. I wrote the procedure for this on this sight a couple of years ago. Don't know if it was added to the tech section. Hope this helps. Dave Russell.

Guest · Posted: Thu May 31, 2001 6:02 pm Post subject:

From: dave2
Email: david.c.russell@lmco.com
Date: 31 May 2001
Time: 18:02:13

First off, a voltmeter cannot be wired in serial with anything. Ampmeters can be wired in serial, voltmeters must be wired in parallel. Also, a voltmeter does not "see" power. Power is a measurement of the heat expended, usually in watts. Voltage is the measurement of potential energy, in volts. That being said, your alternator should be putting out between 13.5 and 14.5 volts under normal operating conditions. You have two possible conditions, either your volt meter is not reading the correct voltage, or your alternator is not putting out enough voltage. You can isolate the problem by using a multi-meter to read the voltage across the two battery posts. If it is the same low voltage that your in dash voltmeter is reading, the problem is with the alternator. It may be as simple as a bad ground, or slipping belt. Simply cleaning the grease off will not cure the problem. However, a low voltage reading in the ten volt range is usually caused by on on the diode rectifiers in the alternator being open (not functioning). If you have the alternator checked by a mechanic, or in a parts house, they may diagnose this as a shorted diode, but it is not a short, it is an open. My bet is that that is your problem. This is a common problem with Bosch alternators. You will have to replace the alternator to cure this problem. It is not a "Porsche" alternator. Therefore finding one from a VW, Audi, BMW or Mercedes will not change the price. If you want it to fit the same, you will need the same model Bosch that is currently installed in your 924. I replaced the stock Bosch unit in my '80 931 with a Delco (GM) unit from a '86 Camero in 1987, and have never had another problem. It cost me $25.00 back then, and has a lifetime guarantee. I wrote the procedure for this on this sight a couple of years ago. Don't know if it was added to the tech section. Hope this helps. Dave Russell.