Voltage Regulation from PCM
10-29-2008, 05:30 PM
#1
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Voltage Regulation from PCM Took car in for electrical diagnostic to try and take care of flickering lights (all) and volt guage. Alternator tests good on machines from auto parts stores. Mechanic said it is one of 2 things, but he cannot tell which.
1. Voltage Regulation from Alternator
2. Voltage Regulation from PCM itself.
A new Alternator is around $100, and I have no idea what a new PCM costs.
The two specifics I got from him were that the regulation is actually pretty close, just not "right on". Second was that it was running right at 13.7-14, and then one, and only one of the times he revved it whilst checking it out, he saw the volts drop down to 12.
I have been told that if it is actually the computer, then all it can really do is annoy me with the flickering lights, that it will not actually affect how the car runs. To that end, it does not seem to.
In the next few weeks, I was planning on getting a full dyno tune done. Can this issue affect the tune, or ability to have it done ?
Chewie
1. Voltage Regulation from Alternator
2. Voltage Regulation from PCM itself.
A new Alternator is around $100, and I have no idea what a new PCM costs.
The two specifics I got from him were that the regulation is actually pretty close, just not "right on". Second was that it was running right at 13.7-14, and then one, and only one of the times he revved it whilst checking it out, he saw the volts drop down to 12.
I have been told that if it is actually the computer, then all it can really do is annoy me with the flickering lights, that it will not actually affect how the car runs. To that end, it does not seem to.
In the next few weeks, I was planning on getting a full dyno tune done. Can this issue affect the tune, or ability to have it done ?
Chewie
10-30-2008, 10:10 AM
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Done always believe the "electrical diagnostic" at a garage or parts store. My alternator on my 2002 had only 25,300 miles on it is all and my lights flickered too. Especially when at idle, or just off idle. My voltage was wacky too. The diagnostic test showed everything was fine. I replaced my alternator with a new factory one and now all flickering is gone, my charge voltage is back, everything is solidly bright when my lights are on. This is a common problem with those GM alternators apparently. There are a lot of posts with the same problem description.
10-30-2008, 04:27 PM
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Done always believe the "electrical diagnostic" at a garage or parts store. My alternator on my 2002 had only 25,300 miles on it is all and my lights flickered too. Especially when at idle, or just off idle. My voltage was wacky too. The diagnostic test showed everything was fine. I replaced my alternator with a new factory one and now all flickering is gone, my charge voltage is back, everything is solidly bright when my lights are on. This is a common problem with those GM alternators apparently. There are a lot of posts with the same problem description.
10-30-2008, 04:38 PM
#5
Parts store machine is just a static test. With no load, the alternator could be fine...but throw in a small load (ecu, lights, etc.) and you might have issues. Parts store machine can't test that. Parts store "on car" test is just as reliable (or unreliable). It test the charging system as a whole...not each individual component.
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10-31-2008, 06:01 PM
#9
i would fix it before the dyno tune injector offset changes with voltage
in a perfect world it would be the same but jumping from 14.1v to 12v is
a big jump it might overshoot. tuning is too expensive to take a chance on it
getting an effed up logfile and tuning around an intermittent charging problem
i agree with the above posts a new alternator will fix it
in a perfect world it would be the same but jumping from 14.1v to 12v is
a big jump it might overshoot. tuning is too expensive to take a chance on it
getting an effed up logfile and tuning around an intermittent charging problem
i agree with the above posts a new alternator will fix it
