Is my alternator dying?
07-05-2005, 01:47 PM
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Is my alternator dying? I have a stock 2001 Camaro Z28 with about 57k miles. Over the last four weeks, I’ve had issues when starting the car. Issue first occurred after I installed my aftermarket stereo. Installation included installing a new battery terminal and running a power wire from the positive terminal through the grommet below the PCM back to a small amplifier (like 200 watts or something). In order to reach the grommet, I unplugged and removed the PCM. After I ran the wire through I put the PCM back in and tightened the connections into place. However, during this process the rubber weather-stripping around the connections came off and I couldn’t get it back on. I don’t know how important that rubber stripping is.
When I first tried to start the car, nothing happened; I thought I’d broken something. I had absolutely no electronics, no lights, radio, or power locks, etc. But, later in the day it started up just fine.
Since then I’ve had about 6 episodes when the car will turn over, but not stay running after I start it. The engine fires up, but then either runs incredibly rough, and then dies, or just dies right away. I can give it some gas and rev up the motor, but as soon as I let off it runs rough again and quickly dies. This happens two or three times in a row, and then the car starts up and operates normally. Twice I’ve turned the key and lost all electricity again. It may have been some kind of short circuit, because all the stored settings on the radio were reset. Once, the car just came back after a minute by itself again, the second time I tested the battery terminal to see if it was loose (it wasn’t) and the car started up again. These "won't stay running" episodes are increasing in frequency, so something is breaking down.
The whole time I’ve noticed that my battery charge indicator during operation is below normal, leading me to suspect a dying alternator. However, the complete loss of electricity is disturbing me, and I want to know if there is anything I could have done to the PCM when I removed it that would cause these types of symptoms. I believe the PCM is a lot more expensive to replace then the alternator.
When I first tried to start the car, nothing happened; I thought I’d broken something. I had absolutely no electronics, no lights, radio, or power locks, etc. But, later in the day it started up just fine.
Since then I’ve had about 6 episodes when the car will turn over, but not stay running after I start it. The engine fires up, but then either runs incredibly rough, and then dies, or just dies right away. I can give it some gas and rev up the motor, but as soon as I let off it runs rough again and quickly dies. This happens two or three times in a row, and then the car starts up and operates normally. Twice I’ve turned the key and lost all electricity again. It may have been some kind of short circuit, because all the stored settings on the radio were reset. Once, the car just came back after a minute by itself again, the second time I tested the battery terminal to see if it was loose (it wasn’t) and the car started up again. These "won't stay running" episodes are increasing in frequency, so something is breaking down.
The whole time I’ve noticed that my battery charge indicator during operation is below normal, leading me to suspect a dying alternator. However, the complete loss of electricity is disturbing me, and I want to know if there is anything I could have done to the PCM when I removed it that would cause these types of symptoms. I believe the PCM is a lot more expensive to replace then the alternator.
07-07-2005, 06:31 PM
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First thing I would do is undo everything related to the stereo and recheck everything you took off or took loose to install the stereo. See if that helps. Did you put a fuse in the power wire you ran from the battery? Check the other wires coming through the gromet in the fire wall. Maybe they got damaged with that power wire there.
The weather stripping you could not get back on? Are you talking about the rubber seal on the computer connectors? They need to be on to keep moisture out.
Take a look at the connectors for pins that may be pushed out.
The weather stripping you could not get back on? Are you talking about the rubber seal on the computer connectors? They need to be on to keep moisture out.
Take a look at the connectors for pins that may be pushed out.
07-07-2005, 06:33 PM
#4
First check open-circuit voltage on your battery, with the key off (just hook up a DIGITAL voltmeter, positive to the positive battery terminal, negative to negative). You should get about 12.5 to 13.2 volts if your battery is fully charged and there is no drain on it. Next, start up the engine and do the same thing again. With the engine running, this is known as Charging Voltage. It should be about 13.0 to 14.5 volts, and it definintely should be higher than the open-circuit battery voltage (with the engine off).
If your battery or alternator is taking a crap, you will definitely get symptoms like you've described, since the engine-management electronics need a good, stable voltage supply to operate properly. Also check all your connections (especially your battery terminals) to make sure there's no problem there. Another good test might be to disconnect your sound-system power supply, since they can often draw a lot of current and "pull down" the voltage you need to run the engine.
If open-circuit voltage is low, charge the battery and see if it comes up. If not, you've likely got a bad battery. The next step would be to load test the battery (take it to an auto parts store). Sometimes even a battery that will hold a charge will crap out under load.
I've found problems often emenate from the last thing done on a car. I would definitely check for a power problem first, but if your power supply is stable, you might want to CAREFULLY disconnect the PCM and look for a damaged/dirty connector, then reseat the connector solidly.
If your battery or alternator is taking a crap, you will definitely get symptoms like you've described, since the engine-management electronics need a good, stable voltage supply to operate properly. Also check all your connections (especially your battery terminals) to make sure there's no problem there. Another good test might be to disconnect your sound-system power supply, since they can often draw a lot of current and "pull down" the voltage you need to run the engine.
If open-circuit voltage is low, charge the battery and see if it comes up. If not, you've likely got a bad battery. The next step would be to load test the battery (take it to an auto parts store). Sometimes even a battery that will hold a charge will crap out under load.
I've found problems often emenate from the last thing done on a car. I would definitely check for a power problem first, but if your power supply is stable, you might want to CAREFULLY disconnect the PCM and look for a damaged/dirty connector, then reseat the connector solidly.