1993 k1500

Tiny
SWENSON
  • MEMBER
  • 1993 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
I have a 1993 chevy k1500 silverado and just the other day I got in it and started it up and the battery light was on and the battery guage was almost all the way on the low mark. I just replaced the battery and alternator a couple weeks ago so I don't think it could be that. Also when I start it up it idles at 2000 rpms when in park and 1500 rpms when in gear and I haven't changed anything this all just randomly happened. I cant fingure anyting out can anyone help me? I can't even listen to the radio when its running it just turns on and off. Also a few months ago I realized that after I shut the truck off the windows still roll up and down without the key on
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Wednesday, March 2nd, 2011 AT 3:42 AM

5 Replies

Tiny
CARADIODOC
  • EXPERT
Beginning with the '87 models the GM generator is an extremely poor design. It is very common to go through four to six of them in the life of the vehicle. You already did what has been found to be most effective at reducing repeat failures. That is replacing the battery at the same time.

To verify if the new generator is defective, use an inexpensive digital voltmeter to measure battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. If it is closer to 12.6 volts or less, double-check the voltage on the output stud on the back of the generator. On the rare chance it is higher there, look for a break in that fat wire that goes to the battery.
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Wednesday, March 2nd, 2011 AT 4:50 AM
Tiny
SWENSON
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If the alternator was faulty wouldnt the battery be dead from not charging? And also do you have any idea about the idle problem
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Wednesday, March 2nd, 2011 AT 5:53 AM
Tiny
CARADIODOC
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Not necessarily a dead battery. Since it's new it should be strong enough to run the fuel pump, head lights, and ignition system for a good hour or longer before it runs dead. I wouldn't be concerned about the idle speed just yet until the charging system is working. There's a number of computers on the truck that will do weird things when the system voltage is low. The same is true of the radio. You might be able to prove that by running the engine while a battery charger is connected and set on a low setting but keep in mind a working generator puts out a three phase output which is very steady with low ripple. A battery charger puts out a pulsing DC voltage that varies from 0 to about 18 volts 120 times per second. That too might affect some computers.

Another cause of high idle is a vacuum leak. GM has had a lot of trouble with leaking intake manifold gaskets but they usually leak coolant. Also, I think that became a problem after '93 models.

If something is not turning off with the ignition switch that allows the windows to still work, there should be other things on that circuit that also still work. That might include the radio, heater fan, or dash cluster.
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Wednesday, March 2nd, 2011 AT 6:45 AM
Tiny
SWENSON
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Ok so step by step what do you recommend I do to fix my problem.
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Wednesday, March 2nd, 2011 AT 1:48 PM
Tiny
CARADIODOC
  • EXPERT
To verify if the new generator is defective, use an inexpensive digital voltmeter to measure battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. If it is closer to 12.6 volts or less, double-check the voltage on the output stud on the back of the generator. On the rare chance it is higher there, look for a break in that fat wire that goes to the battery.

If the voltage is lower than 13.75 volts at the battery and at the generator's output stud, it is either the belt is slipping severely, (doubtful), or the generator is defective. The only other thing that could be wrong is the "turn-on" circuit, but then the battery warning light would not work.
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Wednesday, March 2nd, 2011 AT 3:41 PM

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