alternator question
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New User
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alternator question
Can I please ask you guys a question about my 92, 2.3 with fuel injection?
I replaced the alternator this last, but a friend of mine pulled the positive cable on my battery this morning while the truck was running, the engine died, and he says I still have a charging problem. Is he right? Is my truck’s engine supposed to die without the positive battery cable attached?
Any help would be greatly appreciated, I'm in alot of trouble if he's right.
I replaced the alternator this last, but a friend of mine pulled the positive cable on my battery this morning while the truck was running, the engine died, and he says I still have a charging problem. Is he right? Is my truck’s engine supposed to die without the positive battery cable attached?
Any help would be greatly appreciated, I'm in alot of trouble if he's right.
Posting Guru
Joined: Dec 2003
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From: Maine
I think that's normal.
Did your friend disconnect it because you weren't sure if it was charging, or just to "check it"? If you want to see if it is charging, grab a multimeter and measure the voltage across the battery with the engine idling. I'm a little fuzzy on what the numbers should be, but it is higher than 12. Maybe someone can chime in and remind me...
Did your friend disconnect it because you weren't sure if it was charging, or just to "check it"? If you want to see if it is charging, grab a multimeter and measure the voltage across the battery with the engine idling. I'm a little fuzzy on what the numbers should be, but it is higher than 12. Maybe someone can chime in and remind me...
Senior User
Joined: Oct 2005
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From: ventura, CA
Use a voltmeter for a scientific/quantitative answer as to if your alternator is working.
Pulling a positive lead off your battery while the engine is running can cause huge voltage spikes and damage electronic components on your truck - including the ECU.
Pulling a positive lead off your battery while the engine is running can cause huge voltage spikes and damage electronic components on your truck - including the ECU.
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Because I wasnt sure it was charging. I know i was wrong to let him pull that wire and it wont happen again. Thanks for reminding me.
I will do the volt meter check within an hour or so. It just blew my mind that the engine died without the battery. Believe me I love my truck and I dont want to damage it.
Thanks so much for the quick response.
I will do the volt meter check within an hour or so. It just blew my mind that the engine died without the battery. Believe me I love my truck and I dont want to damage it.
Thanks so much for the quick response.
Fleet Owner
Joined: Jan 2004
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From: Brentwood,CA
the engine should have stayed running. the battery is only there to provide storage and cushion voltage spikes.
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It's a new alternator though. Maybe bad wires or something?
I just did the voltage check and I'm getting 14 volts. It took a minute to get that reading but thats where it finished up. I dont know what to think now.
I just did the voltage check and I'm getting 14 volts. It took a minute to get that reading but thats where it finished up. I dont know what to think now.
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Laughing Gas
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Look to see if your ground strap from the back of the motor to the firewall is still intact. If you pull the positive battery cable, you've created an open circuit for anything that grounds to the block if that strap has corroded.
Elder User
Joined: Sep 2005
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From: crete, illinois
you may have gotten a bad alternator. i'd take it back where i got it and have them do a load test or just ask for another one. my wifes hyundai did the same thing after i changed it, then i had my mechanic bud work on it and it still wasn't right. finally got fed up with it and gave the car to her dad and we went and got another ranger. he took the alt. off, went and got another one and its been fine since.
thats ok i hated that darn car anyway! good luck.
thats ok i hated that darn car anyway! good luck.
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It looks like theres a short somewhere. The manual calls for a volatge check between the neg post and the cable, and I'm getting volatage there. Ive pulled all the fuses and i cant seem to lose the short. I"m going to replace the battery cables next. One thing thought. One thing though. afew days back the blinkers went out. I replace the flasher but that didnt fix it. Column switch?
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Joined: Oct 2005
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From: ventura, CA
Voltage between what two points? From the negative battery post and the shell of the alternator? If so then you have a grounding problem, and that isn't fused.
Turn on your headlights and start up the engine.
Measure from the negative post of the batt to the negative terminal of the cable itself at the battery. This shouldn't measure any voltage. Repeat the same thing with between the battery and engine block. This too should be low but will show some reading due to cable losses. Forget what the # should be but probably 50mV or less is okay.
Turn on your headlights and start up the engine.
Measure from the negative post of the batt to the negative terminal of the cable itself at the battery. This shouldn't measure any voltage. Repeat the same thing with between the battery and engine block. This too should be low but will show some reading due to cable losses. Forget what the # should be but probably 50mV or less is okay.
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sorry probedude I'm a little confused. the haynes manual says to turn the key to the off position and measure between the neg battery post and the disconected neg battery cable and there should be no voltage. I get 12 volts.