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It all started with a bad freeze plug?

Tiny
ROBERT WATSON4
  • MEMBER
  • 1997 CHEVROLET TRUCK
  • 4.3L
  • V6
  • 2WD
  • AUTOMATIC
  • 300,000 MILES
The truck ran fine, had a freeze plug go bad rust ate it up and water was pouring out on ground jacked truck up to work on. Freeze plug and when I finished wanted to test drive and the truck want start crank but know start replaced ignition model coil plugs wires router and cap replaced crank shift sensor and connector to sensor also connector to ignition model in the last time I ask? You said the pink wire to coil should be hot when the key is turned on its not two shops later I had to pull truck back home in I I was told there is a short in the harness somewhere in they were not that kind of shop I guess so I thought I would try it with your help to find the short it way above my pay grade but have no choice I know the wires to brake and turn signal blinkers and horn not responsible witch wire could be responsible for the crank but know start could be the reason I know the pink wire to coil is not hot when you turn key on ran a hot wire from battery to coil in still crank no start in thing you can tell me would be appreciated.
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Friday, March 31st, 2023 AT 4:44 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,244 POSTS
Hi,

I attached a pic below of where the power supply starts for the ignition coil. Check the fuse first.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If the fuse is good and has power, the next concern is the large splice where multiple wires come together. We may have an issue at that point.

Let me know what you find.

Joe

See pic below.
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Friday, March 31st, 2023 AT 11:12 PM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
10.5volts to the coilbut no spark from coil to. Distribter new coli. Rand new
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Saturday, April 1st, 2023 AT 2:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,244 POSTS
Hi,

Do you have a live data scan tool? If you do, connect it and see if there is an RPM signal from the CKP. I realize it is new, but we need to confirm there is a signal from it. If you don't have a live data scanner, watch the tachometer to see if it moves a bit when cranking,

Also, I need confirmation on power to the coil. Your original post said there was no power. (See pic below) The last post says 10.5v to the coil. Please confirm for me.

Take care,

Joe

See pic below.
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Saturday, April 1st, 2023 AT 3:02 PM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
Yes, I'm getting10.5 volts to coil by the pink wire but no spark from the coil to the distributor. I replaced the crank shaft sensor. What other sensors would cause a crank but no start? Prob no fire at all using starting fluid to try to start truck but there's no smoke no pop no backfire no cough or even a sputter.
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Sunday, April 2nd, 2023 AT 1:54 AM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
Yes I'm getting10.5 volts to coilbye the. Pink wire but no spark from the coil to the distributor I replaced the crank shaft sensor what other sensors would cause a crank but no start prob no fire at all using starting fluid to try to start truck but there's no smoke no pop no backfire no cough or even asputter
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Sunday, April 2nd, 2023 AT 1:54 AM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
What do the 2 other wires going to the coil do? One is from the ignition model pink wire from harness powers the coil in another tan wire from harness what do they do no? Voltage out of the other two wires only the pink wire 10.5 volts.
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Sunday, April 2nd, 2023 AT 2:05 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,244 POSTS
Hi,

There should be 3 wires. The pink is the power supply as you know. The solid white wire sends a tachometer signal to the tach in the vehicle. The black wire with a white tracer goes between the coil and ICM and provides a tach signal. See pic below.

Let me know if this helps.

Joe
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Sunday, April 2nd, 2023 AT 6:03 PM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
The pink wire to coil 10.5 v that normal and what other sensor could crank no start pro have replaced crank shaft sensor and had to splice wire to the connector a schematic of the wires to crank shaft sensor would be appreciated you are appreciated think you.
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Sunday, April 2nd, 2023 AT 7:51 PM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
The pink wire to coil 10.5 v that normal and what other sensor could crank no start pro have replaced crank shaft sensor and had to splice wire to the connector a schematic of the wires to crank shaft sensor would be appreciated you are appreciated think you
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Sunday, April 2nd, 2023 AT 7:51 PM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
Please help, this truck has been in two shops and now it's back home. No one in this small town wants to work on it. I've been told there a short in the wiring harness in that is way above my pay grade. Can you help? Anything you can do is appreciated.
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Monday, April 3rd, 2023 AT 7:41 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,244 POSTS
Robert,

I would be happy to help. Let me know exactly where we are after the shops have checked it. For example, did they give you an idea of where there could be a short or anything that would help me diagnose it? Not being there makes it a lot more difficult, but usually, I can figure it out.

Let me know.

Joe
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Monday, April 3rd, 2023 AT 8:23 PM
Tiny
ROBERT WATSON4
  • MEMBER
  • 14 POSTS
Is there a knock sensor on this model truck and would it cause it to crank but no start any other sensor I should check the o2 sensor is bad, but I have taken it I out of the exhaust, it still hooked up to the wires so it okay. The last mechanic that I paid told me that he thought there was a short some ware in the wiring harness. I just wish which wires would make it crank but know start for example the wires to the blinkers that not a wire that would make a crank but no start problem the wires to the horn that's not a crank but no start wire so the only wires would be an ignition wire or a sensor wire or a fuse. Am I righ? Please help with any knowledge you have with this crank but no start not even a back fire or a puff of smoke not even a sputter using starting fluid.
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Tuesday, April 4th, 2023 AT 4:48 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,244 POSTS
Robert,

I realize there is no spark, but like you, I need to know a few things. I realize the CKP has been replaced a few times. I also realize there was a wire splice done to the connector, but I need to know if there is an RPM signal when it is cranking to eliminate the CKP circuit.

If you don't have access to a live data scan tool, see if the tachometer moves a little when cranking.

As far as other sensors that would prevent it from starting, there really aren't any, other than the CKP that would prevent spark. That is why I'm questioning if there is a signal.

Let me know.

Joe

Have you checked the coil itself? I know it is getting voltage but that doesn't mean it's good.
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Tuesday, April 4th, 2023 AT 7:13 PM

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