It's not between the alt and the battery. Both tests were done at the alt, with and without accessories on. Maybe I wasn't clear.
Low voltage
- Thread starter HiTech6
- Start date
Just got back from Oreilly's. Battery tested good at 13.4 volts. Then as I added load, tester dropped to 12.4 volts and "bad voltage regulator" popped up on screen. So it seems the alternator is bad. Anybody buy one from Kirban's lately with "the correct pulley"?
I've got led down the wrong rabbit hole a couple times with those parts store alternator testers in the last few months.
Keep in mind, the battery and the alternator is connected by one thick wire under the hood. Assuming that wire is still good and clean, etc... They will pretty much always share the same voltage.
Now inside the car is another story. Voltage has to go from the battery, to the starter, through the fuseable links, through the bulkhead, through the ignition switch, etc...
A quick test would be to measure voltage at idle will all your accessories on. Hit the alt post, and not the reading... Then go to the battery, same thing, then the hot side of the ign switch, then the output side of the ign switch. If, for example, the hot side if full voltage (minus a few tenths) and the output side if 1.5 volts light, you just found your problem.
Keep in mind, the battery and the alternator is connected by one thick wire under the hood. Assuming that wire is still good and clean, etc... They will pretty much always share the same voltage.
Now inside the car is another story. Voltage has to go from the battery, to the starter, through the fuseable links, through the bulkhead, through the ignition switch, etc...
A quick test would be to measure voltage at idle will all your accessories on. Hit the alt post, and not the reading... Then go to the battery, same thing, then the hot side of the ign switch, then the output side of the ign switch. If, for example, the hot side if full voltage (minus a few tenths) and the output side if 1.5 volts light, you just found your problem.
At this point I know the voltage at the battery, alternator, and scan tool (hooked to ALDL port) all showed 12.4 volts with everything on, +- .1 . I ordered a new AC Delco ignition switch and a new 120 amp alternator from Kirban. I am starting to hate fixing things after they break. With 200k miles on the car I need to be more pro-active. VDO speedometer also broke last week and VDO no longer makes a replacement. The Autometer one does not match my other gauges and it will cost $120 to restore the VDO unit. It's like raising a kid!
This one looks close but then I need the GPS sender for $105. How do you hook it all up? http://www.summitracing.com/parts/vdo-437153
Superrmario
Member
- Joined
- Nov 6, 2013
Welcome to owning a Turbo Buick my friend. Purchased mine in February and have roughly half of what I paid for it, back in it. Engine build, tires, wheels, wiring, scan tools and loggers, gauges, fuel pump blah blah. You get the point.
BTW, I still haven't touched the body yet. That's another 5k+
Been there done that.
that one doesn't look like a GPS speedo, I think it's an electric unit that want's pulses per mile. Seems like you have to have an adapter that converts cables to pulses to use that one.
The one thing I forgot to mention is I think most GPS units have an hour meter instead of a odometer. I'm guessing there has to be some with odometers since they know velocity and time.
I've decided I will just get mine repaired. Worked fine for 10 years and no extra wires to run. On a side note I can't get the volts bulb to light in the dash. I tested the bulb and it is good. Previous owner installed a field fix so I never had a charging problem (except for the fact that my alternator is bad and I ordered a new one from Kirban). I'm hoping I can find a little bulb with a socket at parts store. I still would like the bulb to light, at least to indicate if the alternator goes bad.
TurboTdr3.8
Well-Known Member
- Joined
- Jan 15, 2013
I changed my + and - cables from Casper s and that fixed a lot of my electrical issues that I was having with my car
I've had two wire issues that I can recall...green wire to A/C compressor broke, and white wire to tach broke. I just found the receipt from Advance for the alternator, dated 11/9/12, $125, lifetime warranty. Brand is Remy Power Products. I also ordered a new power window motor for passenger door from Rock Auto. Had a $25 gift certificate (door prize for entering a car show)
I've just joined the club. Took new alternator from Kirban's to Oreilly and the machine tested good with it off the car. Installed it on car and again volts dropped to low 12 range on battery under load. Went back to Oreilly and now their hand held tester says bad battery AND bad alternator. Drove to Interstate where they tested each battery cell with a hydrometer. All cells tested good. The guy there said it is ok for volts to drop into 9 volt range
under load as long as the volts come back up to 13ish with no load. So now I took the original alternator back to Oreillys (the one that tested bad) and their machine says it PASSED. the window motor doesn't have anything do to with the running condition but voltage can be a good warning shot.
Keep in mind voltage inside the car will NEVER read higher than under the hood. If there's a component that causing voltage drop anywhere in the wiring it makes that drop by converting contact into heat. These cars run on electricity.
I'd have to look at the schematics to be more specific but I'm pretty sure the ECM and the IGN module get a switched power from the ign switch.
Keep in mind voltage inside the car will NEVER read higher than under the hood. If there's a component that causing voltage drop anywhere in the wiring it makes that drop by converting contact into heat. These cars run on electricity.
I'd have to look at the schematics to be more specific but I'm pretty sure the ECM and the IGN module get a switched power from the ign switch.
Superrmario
Member
- Joined
- Nov 6, 2013
Pretty sure you're correct on the ECM Earl. I fought hard with this senerio. Voltage displayed on my volt gauge was 13.5v+ but my Powerlogger only saw 12.x volts from the ECM. Chased power and grounds everywhere and after reading a few of your posts as well as a few chats with S. Wood I narrowed it down. Cleaned the switch and connectors with a wire brush and a scribe, a little dielectric grease and my PL reads pretty much what my Guage sees.
I'm about to take my entire dash apart to do some custom wiring, mods, HVAC maintenance, and a pretty in-depth alarm system.
I've got a mental image of a pretty simple circuit in my head to fortify the crap out of the cars wiring. I just need to sit down with the shop book and see what it would take to deprive flaky, aged components the ability to lower voltage. Sorta like a hotwire kit for the whole car.
I've got a mental image of a pretty simple circuit in my head to fortify the crap out of the cars wiring. I just need to sit down with the shop book and see what it would take to deprive flaky, aged components the ability to lower voltage. Sorta like a hotwire kit for the whole car.
Don't forget pictures!
