6.2 diesel loosing 12v on the IP shutoff solenoid

[Dieselbrent]

I am in need of some help. I have e 1987 chevy 6.2 diesel and I am loosing 12 volts to the fuel shutoff on the injection pump. It runs for 30 seconds then cuts off. The solenoid reads 11 or 12v when running then it instantly goes to 2 volts and shuts-off. I am looking for a injection pump wiring harness and I can't find one anywhere on the web.

 

[Snoots]

Check your oil pressure sender. If they think you don't have enough OP the computer will shut off the fuel pump.

 

[Itali83]

Check your oil pressure sender. If they think you don't have enough OP the computer will shut off the fuel pump.

6.2 diesel. No computer. Oil pressure sensor has nothing to do with shutoff solenoid.

Ok, that out of the way, I’d be checking the single wire that goes to the shut off solenoid itself. It’s the pink wire on top of injection pump. If you haven’t noticed, these motors shake a little bit…. I’d be looking for it chaffing on the motor somewhere first. Along the intake, a bracket etc etc. it’s in a small wire loom where there is a chance of it chaffing. It still has a chance of it chaffing closer to the firewall when it joins the big harness too. Start there and report back

Ben

 

[Blue Ox]

You probably mixed up the wires for the shutoff solenoid and the cold advance solenoid. Fat red wire goes to the terminal on top of the pump cover. Small green goes to the one on the side of the cover.

 

[Dieselbrent]

Okay I traced the red wire down and it was in great condition. I am now looking at the relay for the glow plugs. Maybe that is causing it to somehow loose power. And I'll work back from there. I also looked at all my plugs on the top of the injection pump. Everything is in the correct order. I appreciate all the advice and help. I will give an update when I put the glow plug relay on. One side goes to battery and other goes to the glow plug and to the shutoff solenoid. So I am hoping this helps my electrical short and the decreasing voltage.

 

[Itali83]

You can always unhook the red wire and put a jumper directly from the battery to rule out a faulty shut off solenoid. Be 100% sure it’s a power supply problem and not a solenoid problem.

Ben

 

[Rickf]

Don't forget about where the harness goes thru the firewall or the switch on the steering column.

 

[Dieselbrent]

Okay thank you for the help. I will check on all that.

 

[Dieselbrent]

I checked the injection pump with a jumper and the solenoid was good. I loose the wire in the firewall.