problem voltage c4
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Navigator
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problem voltage c4
dear user corvette c4 , sorry for my very translate english , but i am french . i have he problem with my corvette c4 1986, i have red light inside car and when i start corvette the battery up 14,5 ; 15 ; 16 , 17 18 volt ( i not check more i cut contact ) i buy new alternator , because for me is regulator , battery is new , now i have any idea . if you can help me ......
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best regards alain
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Navigator
Joined: Mar 2017
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thank jim , i cheek , not easy because start very well , power at battery and power at alternator ; i think it s the regulator not receive ( come back voltage from batterie ) to regulation , but not easy to check witch wire is problem . i push each plug , control screw , i am not he best in electric problem, and no corvette in france ( i order my part in USA ). i come back to my corvette to check . thank for your message .
best regards alain
best regards alain
Melting Slicks
Joined: Jan 2014
Posts: 2,478
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From: Downers Grove Illinois
Did this start happening after you put the new alternator in? If so, I think you got a bad one.
Jim
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no , the problem star with hold one , i buy new one because in my idea it's regulator not work , but new one is same , no power it's easy , but to lot of power .....
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Navigator
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it's new battery to , no possible to buy "corvette battery in france , i buy one from germany in "special us batterie shop "but i am not sure if is ok , is just 12 volt 650A ; Possible it's battery problem ? , the car star very well
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Pro
Joined: Aug 2015
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From: Jackson Wisconsin
It sounds like a faulty voltage regulator. According to an old C4 thread 18v will destroy your ECM. I'd recommend you check this out carefully. It is not unusual to get a defective VR in a rebuilt alternator. An auto repair shop should be able to put your alternator on a test bench and check it out.
Burning Brakes
Joined: Jul 2013
Posts: 1,027
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From: Granite City Illinois
I would check all the grounds on the engine block and wherever you can check, and the pigtails or connectors lots of them this old are kind of messed up connectors or wires even. Do a search for c4 grounds.
If you see 16 volts or more disconnect the battery and measure its voltage right away to see if it stays high, use a decent volt meter, or confirm its reading accurately. It could even be the volt readout is inaccurate in the car, but the voltage climbing doesn't seem likely to point that way to me. Always check though
If you see 16 volts or more disconnect the battery and measure its voltage right away to see if it stays high, use a decent volt meter, or confirm its reading accurately. It could even be the volt readout is inaccurate in the car, but the voltage climbing doesn't seem likely to point that way to me. Always check though
Last edited by ToniJ1960; Mar 27, 2017 at 08:01 PM.
Flatulent Dwarf
Joined: Nov 2009
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From: Poverty Holler NC
dear user corvette c4 , sorry for my very translate english , but i am french . i have he problem with my corvette c4 1986, i have red light inside car and when i start corvette the battery up 14,5 ; 15 ; 16 , 17 18 volt ( i not check more i cut contact ) i buy new alternator , because for me is regulator , battery is new , now i have any idea . if you can help me ......
later, tiny
Team Owner
Joined: Dec 2012
Posts: 30,427
Likes: 1,609
From: Outside the Quick Stop N.J.
I would take the old (if you still have it) and new alternator to a shop that can test the individual components. Many auto parts stores do this in the US, but I am not sure about France. You might have to find a specialst who rebuilds electrical components to help you out. I would also check out all your grounds, make sure they are clean, tight, and free of corrosion. The battery you have should work just fine. Good luck.
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
dear user corvette c4 , sorry for my very translate english , but i am french . i have he problem with my corvette c4 1986, i have red light inside car and when i start corvette the battery up 14,5 ; 15 ; 16 , 17 18 volt ( i not check more i cut contact ) i buy new alternator , because for me is regulator , battery is new , now i have any idea . if you can help me ......
Don't rely on the dashboard voltage display, use a multi meter and measure at the Battery and at Alternator.
My dash display shows up to 2 volts lower than battery, have tried the usual clean all the grounds and power connections. Just a display issue in my dash, Multi meters are quite cheap and readily available.
Even in France...
I have a 200 amp alternator and never see more than 15 volts, idle output is usually quite low on standard alternators.
Hence check with a multi meter, then check ground strap from engine to frame is ok....
Good luck from far away (Australia)
Safety Car
Joined: Sep 2004
Posts: 3,953
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From: Mission Viejo CA
Are you testing at the battery terminals? This may be caused by a bad connection at the battery cable connectors. Remove the cables from the battery and be sure to get a good clean connection to the battery.
Welcome to the Forum!
Welcome to the Forum!
Thread Starter
Navigator
Joined: Mar 2017
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i "mixed" different idea , alternator is good , connect battery good ( i buy new screw because hold one bad condition ) . i think i am near problem , normally i start directly , i would like to show if the regulator receive voltage , when i turn key first position the dash boar is black ( i not show before because turn directely ), no light , no information , open only when engine turn . i think problem is near , no volt first position , is possible information not come back to regulator and alternator product 18v . now i check why no light at first position key , bad connection inside ? fuse ? . ( and i learn english same time ) .sorry if my translate is bad , i was bad studient and now at 52 year i learn slowly ( i learn because i like american people and american car )
thank again at full people to make this forum site and for this good help
Thread Starter
Navigator
Joined: Mar 2017
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dear jim
now my corvette is completely open . i am sure is not alternator problem .now when i turn key firt position and not start engine i have dash bord open ( i have disconnect alternator ) at the dash board volt is 15v , if i open light , go up to 15,4 . I have sound inside dash panel like capacitor ( sound length 3 or 4 minute after remove key ) . Control battery 12,5 v.full test no start engine ( if i start car volt go up immediately an no possible test with multimeter , i think not safe for dash board .is it possible disconnect dash bord and start engine ? i think is more safe , i not like the sound
if you have new idea ? i not finish control full wire grounds , possible capacitor can t empty .
thank and good week end
now my corvette is completely open . i am sure is not alternator problem .now when i turn key firt position and not start engine i have dash bord open ( i have disconnect alternator ) at the dash board volt is 15v , if i open light , go up to 15,4 . I have sound inside dash panel like capacitor ( sound length 3 or 4 minute after remove key ) . Control battery 12,5 v.full test no start engine ( if i start car volt go up immediately an no possible test with multimeter , i think not safe for dash board .is it possible disconnect dash bord and start engine ? i think is more safe , i not like the sound
if you have new idea ? i not finish control full wire grounds , possible capacitor can t empty .
thank and good week end
Melting Slicks
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
You can test everything separate from the alternator by disconnecting the big red wire going there, but make sure it is well insulated. Then if you start the car the alternator won't be connected to the battery and you can test the other systems. I am not sure what would happen if you try to run the car without the dashboard, but if you keep running voltage that high your ECM (computer that controls engine) and other systems are likely to be damaged.
Race Director
Joined: Jan 2000
Posts: 16,872
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From: Owings Mills, MD 21117
Does this link help with finding the problem?
Great article and thanks for posting. Having a VM is a must have for any trouble shooting. Further, the OP may have an issue with the ignition switch.
Warm Regards,
Mark
Instructor
Joined: Oct 2008
Posts: 193
Likes: 19
From: Stevenston, Scotland, GB
Try this site.. There are a few Corvette owners on here who live in France.
http://www.corvetteclub.org.uk/index...1f75d7f0fe66c9
Bonne chance, mon ami!
http://www.corvetteclub.org.uk/index...1f75d7f0fe66c9
Bonne chance, mon ami!