New 928 Owner, looking for advice on alternator/(!) light.
07-12-2012, 05:25 PM
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New 928 Owner, looking for advice on alternator/(!) light.
I just recently purchased a 1981 928 USA in Edmonton, AB. Can't wait to dig in, as I have been looking for a project/hobby car for years, and this looks like it will be a labor of love, heavy on the labor.
First, the details: Passed safety inspection, but has a slew of "little things" to fix. (interior clips, leaking valve cover gskts, missing rear stabilizer link, needs another alignment etc.) Exterior in fair shape, leather interior looks excellent but is busting loose. Motor runs strong and smooth, as does the suspension. Talked to Porsche dealer regarding tranny, they feel probably needs adjusting. as it doesn't slip, but also doesn't kick down quite right.
Now for the issue at hand: Seller informed me (and confirmed by inspector) that alternator was not charging. Seller siad the previous owner had rebuilt it, but it never worked. The idiot (!) light would flicker at low (<2000) RPM. No prob, I would replace. Drove it home 2 1/2 hrs no prob. Voltmeter didn't register, which the seller stated it never had. (He bought it in '09). Hose and duct not present, will replace. I noticed that as the engine got hotter, the RPM's required for the (!) to go off would increase. Got it back, put in reman Bosch alt , replaced the belt and immediately the idiot light went out when started (after pressing the button for the park brake)
Voltmeter still not registering more than 10-11. After driving around for a while, she stranded me. Battery was completely dead. Got her home and (after purchasing a multimeter) alternator was not exciting. Double checked connections, all good. When I brought it into our company mechanic, we hoisted it and while looking at the wires, found that the exciter connection actually went to ground, not back to the cluster/ indicator. Disconnected improper wire, and then with a test light connected the exciter/batt connections and Eureka! the alternator put out 13.9-14.4 volts (800-1200 RPM). As there is no wire in the area to connect to the exciter, I manually made a light from an ignition source, and it works like a charm. Start her up, the light kicks on for a second, the alternator ignites , voltmeter reads in that 14 range, then the light turns off.
The problem is, now that stupid (!) light flickers again. When it first starts, it is fine. After it warms up and the high idle kicks down to 7-800 RPM, it starts flickering. As I drive it around, just like when the old alt. was in, the RPM needed to keep it off increases to around 3000 RPM. ( My son thinks it's a warning I'm going too slow).
When hot, the alt. puts out about 13.95 V at idle. Also, it looks like my voltmeter reads about 1V low. I have an electric fan, the belt one has been removed. The AC compressor and the Emissions pump are seized up, so I am stuck with that.
Have I grabbed a tiger by the tail?https://rennlist.com/forums/graemlins/icon501.gif
First, the details: Passed safety inspection, but has a slew of "little things" to fix. (interior clips, leaking valve cover gskts, missing rear stabilizer link, needs another alignment etc.) Exterior in fair shape, leather interior looks excellent but is busting loose. Motor runs strong and smooth, as does the suspension. Talked to Porsche dealer regarding tranny, they feel probably needs adjusting. as it doesn't slip, but also doesn't kick down quite right.
Now for the issue at hand: Seller informed me (and confirmed by inspector) that alternator was not charging. Seller siad the previous owner had rebuilt it, but it never worked. The idiot (!) light would flicker at low (<2000) RPM. No prob, I would replace. Drove it home 2 1/2 hrs no prob. Voltmeter didn't register, which the seller stated it never had. (He bought it in '09). Hose and duct not present, will replace. I noticed that as the engine got hotter, the RPM's required for the (!) to go off would increase. Got it back, put in reman Bosch alt , replaced the belt and immediately the idiot light went out when started (after pressing the button for the park brake)
Voltmeter still not registering more than 10-11. After driving around for a while, she stranded me. Battery was completely dead. Got her home and (after purchasing a multimeter) alternator was not exciting. Double checked connections, all good. When I brought it into our company mechanic, we hoisted it and while looking at the wires, found that the exciter connection actually went to ground, not back to the cluster/ indicator. Disconnected improper wire, and then with a test light connected the exciter/batt connections and Eureka! the alternator put out 13.9-14.4 volts (800-1200 RPM). As there is no wire in the area to connect to the exciter, I manually made a light from an ignition source, and it works like a charm. Start her up, the light kicks on for a second, the alternator ignites , voltmeter reads in that 14 range, then the light turns off.
The problem is, now that stupid (!) light flickers again. When it first starts, it is fine. After it warms up and the high idle kicks down to 7-800 RPM, it starts flickering. As I drive it around, just like when the old alt. was in, the RPM needed to keep it off increases to around 3000 RPM. ( My son thinks it's a warning I'm going too slow).
When hot, the alt. puts out about 13.95 V at idle. Also, it looks like my voltmeter reads about 1V low. I have an electric fan, the belt one has been removed. The AC compressor and the Emissions pump are seized up, so I am stuck with that.
Have I grabbed a tiger by the tail?https://rennlist.com/forums/graemlins/icon501.gif
Last edited by TrentonC; 07-13-2012 at 11:46 AM. Reason: Add signature
07-13-2012, 12:54 AM
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The most important thing is you drove it home. There is quite a few of us in Alberta and BC who can help you through the issues. One of our Godfathers is in Kansas for an event but let us know where you are located.
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07-13-2012, 11:40 AM
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Thanks for the welcome......but I am unsure what I need to add?
As for my location, I live near Cold Lake AB. (About 2 1/2 hrs NE of Edmonton)
As for my location, I live near Cold Lake AB. (About 2 1/2 hrs NE of Edmonton)
07-13-2012, 11:50 AM
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The last message in the series should read "pictures!" An inside joke, asking for photos of your car...
The warning light (!) may or may not be from the alternator. Two suggestions:
- The alternator belt must be tight, and not worn.
- Hook an external voltmeter to the system so you will know what is going on. You can use a multimeter, digital voltmeter, or an add-on gauge. You can hook one side to a good ground, and the other side to the main power connections at the Central Electric Panel under the passenger floor, or to the jump start terminal under the hood.
Most electrical problems on the 928 are due to poor connections or poor grounds.
The warning light (!) may or may not be from the alternator. Two suggestions:
- The alternator belt must be tight, and not worn.
- Hook an external voltmeter to the system so you will know what is going on. You can use a multimeter, digital voltmeter, or an add-on gauge. You can hook one side to a good ground, and the other side to the main power connections at the Central Electric Panel under the passenger floor, or to the jump start terminal under the hood.
Most electrical problems on the 928 are due to poor connections or poor grounds.
07-13-2012, 11:51 AM
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And one other hint - stay away from dealerships...
If you can't do most or all of the maintenance, repairs and upgrades to your 928, you will need to buy a lot of lottery tickets.
If you can't do most or all of the maintenance, repairs and upgrades to your 928, you will need to buy a lot of lottery tickets.
07-13-2012, 12:01 PM
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Thanks for the advice. I have hooked up a multimeter @ the batt posts and at the alternator connections, and it consistently puts out just below 14v at low idle after warm up. The belts are all new, and I am basically replacing everything I can reach right off the hop.
I was just looking through the "new members" thread
(yeah..should have probably done that yesterday, but I was all excited to get signed up after my inability to do so @ 928forums.com...I jumped the gun. Oops.) and I will start going through all my contacts and cleaning them.
There are a few things I am a little worried about though:
The seller said the previous owner was a "gearhead" and did lots of repairing to the vehicle, but was poor with electrical. As I think I am the 4th owner, who knows what has gone on under there. That wrong connection to the alt. makes me nervous. Under the console there are all sorts of random, clipped wires going nowhere and it could be a real pain to trace.
Also, I think the seller may have been using a parts car for random things. He stated that he already sold the parts car, a 1980 (although I am taking the engine) My interior is all brown except for the pod, dash and console. Was that an option in the day, or did he take the best pieces and replace them in this one? (He hasn't fessed up either way.)
I know for certain he replaced the speedo (85MPH- change to 220K), and that the mileage doesn't track properly, so there may be some bad connections at the pod.
I am also replacing the column bushing as there is some slop and squeak in there.
As for the pics, I'll get some soon.
I was just looking through the "new members" thread
(yeah..should have probably done that yesterday, but I was all excited to get signed up after my inability to do so @ 928forums.com...I jumped the gun. Oops.) and I will start going through all my contacts and cleaning them.
There are a few things I am a little worried about though:
The seller said the previous owner was a "gearhead" and did lots of repairing to the vehicle, but was poor with electrical. As I think I am the 4th owner, who knows what has gone on under there. That wrong connection to the alt. makes me nervous. Under the console there are all sorts of random, clipped wires going nowhere and it could be a real pain to trace.
Also, I think the seller may have been using a parts car for random things. He stated that he already sold the parts car, a 1980 (although I am taking the engine) My interior is all brown except for the pod, dash and console. Was that an option in the day, or did he take the best pieces and replace them in this one? (He hasn't fessed up either way.)
I know for certain he replaced the speedo (85MPH- change to 220K), and that the mileage doesn't track properly, so there may be some bad connections at the pod.
I am also replacing the column bushing as there is some slop and squeak in there.
As for the pics, I'll get some soon.
07-13-2012, 12:17 PM
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It always zooms straight up to 5, hot or not. As I mentioned, it appears the voltmeter reads a bit lower than what the multimeter shows.
Again, as I think the pod has been off, there might be some connection issues there as well. If the voltmeter thinks it is only putting out 12-ish volts when it is actually 13.9 or so, I wonder if that might make it think something is off...
Oh yeah, one more thing: He says the timing belt & Wp were changed >2000k ago, but of course it was done @ home, no paperwork. I have the tensioner tool and instructions, so I'll check it out, but all the other "little things" make me question the validity of that a bit.
Again, as I think the pod has been off, there might be some connection issues there as well. If the voltmeter thinks it is only putting out 12-ish volts when it is actually 13.9 or so, I wonder if that might make it think something is off...
Oh yeah, one more thing: He says the timing belt & Wp were changed >2000k ago, but of course it was done @ home, no paperwork. I have the tensioner tool and instructions, so I'll check it out, but all the other "little things" make me question the validity of that a bit.
07-13-2012, 12:30 PM
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Also good to know.....Again, thanks for all this help, I'm soaking it up like a sponge.
Would the fact that the valve/cam cover is leaking above the sender/alt. etc. potentially cause an issue?
I have digital copies of the service and parts manuals I bought online, but there isn't much in there ai could find regarding this kind of troubleshooting.
Would the fact that the valve/cam cover is leaking above the sender/alt. etc. potentially cause an issue?
I have digital copies of the service and parts manuals I bought online, but there isn't much in there ai could find regarding this kind of troubleshooting.