Not starting, trying to find crankshaft sensor

Tiny
NOXTUS
  • MEMBER
  • 1994 CHEVROLET SUBURBAN
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 167,000 MILES
There was a bad storm awhile back, I drove through a puddle which I did not think was deep as it was, my truck shut off, I waited some time then cut it back on to a dubious start but a start none the less.

I didn't have anymore problems until it rained a few days later. To which it would crank but would not start this happened a few more times and eventually started happening even when it was not wet outside and eventually just stopped cutting on at all with no crank.

I ended up replacing the wires, distributor cap, rotor, and ignition coil. The distributor cap was in pretty rough shape so I thought that might do it but I've had no improvement.

So after further reading it seems the crank shaft sensor is the culprit, would appreciate anyone's input on this as the case or what might else be the issue.

I am also trying to find the crank shaft sensor, I have found videos and everything else with similar models (GMC 1500, k1500 trucks, etc.) Of people showing where there crankshaft sensor is, but I cannot find where mine is located or any documentation on where it might be located so I would very much appreciate any direction to such or such information.

Thank you!
Saturday, April 18th, 2020 AT 9:11 AM

7 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Your vehicle does not actually have a crank sensor. It uses the distributor to determine crank position and sends this info to the ECM on the distributor ref hi circuit. Circuit 430. Take a look at the info I attached to see more detail.

Let's start from the beginning. When this is not starting we need to check for spark and fuel. Do this by spraying some starter fluid in the intake when it is not starting and see if it fires.

If not, (I assume it won't because I don't think this is fuel either but let's rule it out) then pull a plug and hold it against the block and crank the engine to see if it starts. If it doesn't have spark we can start tracking that but let's confirm it rather then assume it at this point.

Let me know and we can go from there. Thanks

https://www.2carpros.com/articles/car-cranks-but-wont-start
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Saturday, April 18th, 2020 AT 6:01 PM
Tiny
NOXTUS
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Thank you very much, I'm waiting for the weather to clear up and I'll get out there and run those tests.
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Monday, April 20th, 2020 AT 9:24 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Sounds great. Please keep us posted whenever you get to it. Thanks for the update.
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Monday, April 20th, 2020 AT 7:05 PM
Tiny
NOXTUS
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  • 4 POSTS
Alright can confirm no start/crank from starting fluid and no spark from spark plug.
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Thursday, April 23rd, 2020 AT 9:13 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. That is good info. We need to go after the ignition issue because without that, you can all the fuel in the world and it still will not start. Once we get spark, we can readdress fuel if it still doesn't start.

I attached the ignition system testing. We need to run through all of this and see where it leads. Some of the parts you have already replaced but let's just go step by step and see where we end up. Thanks
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Thursday, April 23rd, 2020 AT 5:00 PM
Tiny
NOXTUS
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Alright rotor is rotating there is not spark at the ignition coil either. This beginning more and more to look like some sort of electrical problem. I actually do not have a volt meter so I'll have to go and get one of those today and I'll start checking through looking for a loss of power.
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Sunday, April 26th, 2020 AT 9:27 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. If there is no spark at the coil we need to back track in the system. I attached the info on how it works. However, we need to go back to the PCM and see if we have signal going to the coil. Also, the ignition module and pick up. I suspect your issue is in these parts because if when it happens when it rains that points to a weak spark which would be the pick up most likely.
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Monday, April 27th, 2020 AT 9:40 AM

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