chevy 8.1 crank sensor question

992door

Active Member
Joined
Mar 19, 2009
Location
Winterville, NC
Does anyone know if there is a way to test the sensor? I have been having issues with it just cutting off randomly. Sometimes it would crank right back up and others it would turn over and over for about 45sec then start back up. Thinking it could be crank sensor or fuel pump. Truck is an 01 with 89k on it

Oh and I also had the check engine light come on with the code p1779
 
Last edited:
I thought some vehicles had a recall on the 8.1 crank sensor? I only think I read that because I've been researching getting a 2500 burban. If it's free it's for me.
 
Sounds like it'd be a good idea to replace it.
 
Sounds about right for a 8.1L Crank sensor. All the fleet pickups I had with that motor had access panels cut out of the firewall to get at the sensor. Even then most of them were a royal pain and stuck in the block. Make sure when you install the new one you lube it up good! ;) Not sure of the exact test procedure anymore, but if I recall correctly it is a simple magnetic pickup sensor it should produce an AC voltage while cranking or running.
 
You're not very far away at all. I may be able get some info on it if I was to check it out with my scanner.
 
Well it would not start at the shop yesterday so we put the fuel pressure gauge on it showing it had pressure. Cut the key on spiked to 58-59 then drop back down to 50 and would just turn over 5-6 times then cut the key back off did this 3-4 times before it finally started
 
It should hold 58 constantly. I'd guess it needs a fuel pump or a fuel pressure regulator.
 
NC-V said:
Sounds about right for a 8.1L Crank sensor. All the fleet pickups I had with that motor had access panels cut out of the firewall to get at the sensor. Even then most of them were a royal pain and stuck in the block. Make sure when you install the new one you lube it up good! ;) Not sure of the exact test procedure anymore, but if I recall correctly it is a simple magnetic pickup sensor it should produce an AC voltage while cranking or running.
Click to expand...

Did you cut out the panel our was it already there? It will be nice if that is already there

Sent from my Motorola Electrify using Tapatalk 2
 
Does it only drop down while cranking and then come back up when it runs?
 
Gotcha. This probably isn't the cause of your random cutting off, but it should definitely have 58psi fuel pressure. The same as any GM Gen III engine. It could either be a really dirty fuel filter or a bad fuel pressure regulator. It certainly won't make it run any worse once it has the proper fuel pressure :driver:
 
And another reason I thought about the sensor was because the code p1779 can be caused by the sensor.

Sent from my Motorola Electrify using Tapatalk 2
 
Back
Top