No start?

Tiny
EMONEYBAGS
  • MEMBER
  • 1993 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
Truck listed above is a C1500. It has a brand-new starter, alternator, wires plugs, and was running at that time. Then I noticed my headlights were dim and when I would turn the key over, it would start but did not have the power it should have. I replaced the main ground strap and main power wire from battery to starter. It has a new battery but if I left my headlights on for even a minute or two, I would have to jump my truck. One of the weird things is my old jump box would jump it, every time but when I connected my higher quality jump box up to it, it will never start the truck. When I turn the key, I can hear the starter trying to crank but there's strong hesitation and refuses to turn over.
Saturday, December 17th, 2022 AT 9:48 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,127 POSTS
Hi,

Either you have a major power draw (how quickly the headlamps drain the battery) or the starter is bad and drawing too much amperage.

I need you to check something for me. Disconnect the negative battery terminal and fully charge the battery. Once it is charged, with the negative still disconnected, take a multimeter or voltmeter and place the positive lead to the cable and the negative to the battery negative post. Note the battery itself is still disconnected.

Make sure everything electrical is off and the key is off and removed.

Let me know how much of a draw there is with everything off.

Next, connect the battery. Check the battery voltage with your meter right at the battery. It should be 12+v if charged. Have a helper crank the engine. Tell me how low the voltage drops. It should and needs to stay above 9.6V.

Last, with everything off, check how much of a draw the lights place on the battery when turned on.

Note: Before testing, confirm the battery voltage so we know what we are starting with.

Let me know.

Joe
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Sunday, December 18th, 2022 AT 11:57 AM
Tiny
EMONEYBAGS
  • MEMBER
  • 4 POSTS
Thank you for your reply.

Att= 12.25
Negative disconnected meter between ground and negative battery post is 11.5

With ignition cranked is 9.8
With lights on is 11.8
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Sunday, December 18th, 2022 AT 12:51 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,127 POSTS
Am I reading that correctly? The battery voltage went up with the headlamps on.

Regardless, there is a parasitic draw beyond what is considered normal. If you are drawing .75 volts that equates to 750 milliamps. Normal would not exceed 50 milliamps with everything off.

What I need you to do is this. With the voltmeter connected between the battery neg and battery neg cable (in other words, the negative cable isn't connected to the battery directly but rather, through the voltmeter.)

Remove one fuse at a time until the voltage goes up. Do this and let me know what you find.

Also, take a look at this link. You may find it helpful.

https://www.2carpros.com/articles/car-battery-dead-overnight

Let me know.

Take care,

Joe
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Sunday, December 18th, 2022 AT 9:06 PM

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