19.5 volts on dash
04-16-2018, 04:25 AM
#1
Racer
Thread Starter
19.5 volts on dash
dash volt meter is showing 19.5V, alternator tests good, battery is recently new. Only thing I can think of is volt meter went defective. Still need to test some other points, but need some other clues.
04-16-2018, 05:19 AM
#2
. normal values per FSM, i'm thinking, are 13.5-16V. (I can't recall, ever seeing anything above 14.4V on my 85). in run condition, what's the voltage reading directly across the battery?
Last edited by Joe C; 04-16-2018 at 05:20 AM.
04-16-2018, 05:52 AM
#3
Le Mans Master
Member Since: Oct 2004
Location: South-central Missouri
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post your year. dashboard indicated should never be taken as gospel. 19.5V, if correct, is too high and indicates overcharge condition - . normal values per FSM, i'm thinking, are 13.5-16V. (I can't recall, ever seeing anything above 14.4V on my 85). in run condition, what's the voltage reading directly across the battery?
. normal values per FSM, i'm thinking, are 13.5-16V. (I can't recall, ever seeing anything above 14.4V on my 85). in run condition, what's the voltage reading directly across the battery?
04-16-2018, 05:38 PM
#4
Racer
Thread Starter
04-18-2018, 11:38 AM
#5
Team Owner
Member Since: Sep 2001
Location: Athens AL
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What does your DVM say the voltage across the battery is when the car is running?
Never trust GM voltmeters, check it yourself.
Never trust GM voltmeters, check it yourself.
04-18-2018, 02:01 PM
#6
Race Director
04-18-2018, 07:30 PM
#7
- from the pic, it looks like a side post cable retainer, and that in itself would not cause a high voltage reading, so again, what is the culprit? what is the DVM reading directly across the battery, with the engine running?
Last edited by Joe C; 04-18-2018 at 07:33 PM.
04-22-2018, 02:02 PM
#8
Racer
Thread Starter
14.4 across the batt when running. I replaced the bolt and back to regular voltage. Had the alternator tested, it is good. But I think the bad voltage ruined the computer. I have been testing info in "No info in ALDL" Hopefully today I will get the cables removed from the computer and test to see if B from the aldl is good to the computer, and see if SES is on or not with computer unhooked. Dont know what that is supposed to mean, but it is one of the tests in the FSM. But if both these test go the way I think they will it will end up saying replace Mem-Cal. something to do with the computer, I can get a computer for $350.
04-23-2018, 06:23 PM
#9
Racer
Thread Starter
update
14.4 across the batt when running. I replaced the bolt and back to regular voltage. Had the alternator tested, it is good. But I think the bad voltage ruined the computer. I have been testing info in "No info in ALDL" Hopefully today I will get the cables removed from the computer and test to see if B from the aldl is good to the computer, and see if SES is on or not with computer unhooked. Dont know what that is supposed to mean, but it is one of the tests in the FSM. But if both these test go the way I think they will it will end up saying replace Mem-Cal. something to do with the computer, I can get a computer for $350.
04-24-2018, 09:42 AM
#10
Instructor
04-26-2018, 09:10 AM
#12
Instructor
04-26-2018, 09:32 AM
#14
Instructor
What year car do you have? I have a spare PROM I think for my 1992 6sp. Ill have to check though. I wouldn't mind letting you borrow it if its compatible if you want. Those computers aren't cheap
Connor
Connor