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1990 Dodge D-150 p.u. 3.9L


Elmerine's Avatar
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04-04-02, 07:26 PM   #1  
Elmerine
1990 Dodge D-150 p.u. 3.9L

1990 Dodge D/150 pick-up.I have a new alternator and battery,yet my guage shows low voltage.Other than a bad guage ,what else could be wrong?Also my check engine light comes on then goes off then it repeats this process ,What could be wrong.I am baffled.

 
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04-04-02, 07:58 PM   #2  
well for starters you need to check voltage at the battery to see if your alternater is charging you can take a voltage reading with the engine off and then start engine with all accesories off it should read between 13.5 - 14.7 volts if it doesnt your alternater is not charging correctly. you can not trust the guage on the dash cause it usually isnt very accurate to begin with.
the alternater field is controlled by the pcm and will usually cause a chek engine light if the computer detects a problem with the charging circuit, but there is alot of other sensors that can cause a check engine light also, so you need to check codes by cycling your key on/off/on/off/on and then count your flashes of the check engine light to see what fault code comes up, at the end of the codes it will flash code 55 that is five flashes short pause five flashes, all the codes will be double digits.
post back what you find.

 
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04-04-02, 11:26 PM   #3  
Billdo49er
I've seen numerous alternators that were bad out of the box.Like the other posts states check charge at battery.I never trust the gauge in vehicle.
Also make sure belt is tight.

 
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04-05-02, 04:08 AM   #4  
Elmerine
Thanks for the help.I will do the checks mentioned.

 
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04-05-02, 05:46 AM   #5  
Joe_F
All advice here is right on. I agree with all posted here

 
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04-05-02, 08:19 PM   #6  
Elmerine
Checked alternator ,it was bad.Replaced it with another new alternator and still have the same problem.Could this alternator be bad also?Thanks

 
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04-05-02, 10:20 PM   #7  
Billdo49er
It wouldn't be the first time.(or the last)
Is it a rebuilt or new alt?And what brand?

 
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04-06-02, 07:15 AM   #8  
Joe_F
I agree. Some parts store units are wiped out of the box.

Go with a Mopar/Chrysler reman unit. Better quality and will last longer, albeit cost a bit more.

 
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