alternator issues

Heavy D

Heavy D

New Member
Jun 3, 2009
358
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0
worcester, ma
well i have a 88 7mgte, i put in a new alternator in and i just finished building the motor, car runs fine and drives fine, only thing is the battery light doesnt turn on, all the fuses are fine, i do see 12v from the battery to the alt so i know there is a connection, i checked the bulb in the cluster and thats fine, now i checked to see if i was getting power to the cluster on that one bulb which is the battery and not getting anything, now i did check TSRM for the wiring to the fuses and they check out fine, wanted to know if any one else has any ideas
 
Heavy D

Heavy D

New Member
Jun 3, 2009
358
0
0
worcester, ma
the car is only seeing 11 volts, as I drive the car, it will die out ill give it about 30min before it dies, so basically the car is running off the battery, I went to my job to test the alt, and it is fine, even the old alternator is fine, turbo timer keeps flashing because its not putting out the power that it should, it just keeps getting lower, I checked the fuses and they are fine, I pulled out the fuse box and looked around and they are fine as well, so in order to keep using the car, I have to keep charging the battery manually, but, I only drive it to move it around the house, I did drive it couple times but, don't drive it hard since its not seeing a full power.

btw while the car is running, I took my DMM and see what the alternator was pushing out from the terminal, and it still says 11.8v at idle, revved it, and nothing happen

I also have a code for 51 I believe, now another thing too, I have to jump the b+ on the diag box to the positive on the batter just so the car can run, other wise if it is not connected, ecu will not turn on and car wont run, but I had this issue few years ago before I rebuilt my motor, and from what I remember, I didn't have this issue with the alternator

basically im not getting the 14volts that i should be seeing, not even 13 nor 12, just what the battery is pushing out, so my alternator is not doing its job
 
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Heavy D

Heavy D

New Member
Jun 3, 2009
358
0
0
worcester, ma
is there really a alternator relay for that bulb? also does any one know what the ohms should be pushing out on the 3 pin for the alternator socket? on top of that this new england weather just sucks to work on the cars, as im getting older, its not the same being in the cold when i was younger, even tho i turned 25 today, but i drove the car today with no issues, ill make a video of what the voltages are putting out, and ill try for the amp meter

also i checked the fuses again today, every thing is fine, changed the bulb today, and still nothing, so gonna have to look into the wiring
 
S

super51fan

New Member
Jul 28, 2010
497
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0
Indianapolis
Do you "know it will have 12 volts". Or does it actually have 12 volts where required. Some one is trying to walk you through the way they would go about diagnosing a circuit. And you don't seam to want to do it. IMO Good luck.
 
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