Hi, I have 1995 Suburban 1500
It has the 6.5L Turbo Diesel.
Full tank of fuel.

Yesterday driving down the road it acted like it was running out of fuel.
Stalled and towed home.
No fuel at injectors.
The lift pump only works if I jumper the lugs in the board where the relay plugs in.
It pumps fuel to the filter and out the little drain on the top.

The relay is new the fuel is clean.

I'm leaving the jumper in the board to keep the lift pump working.

What else is operated from this relay?
Would it hurt to leave the jumper in place?
Or could I put in a switch and operate it when running?
Should the lift pump shut off when it reaches a certain pressure?
Is there a fuel pump pressure switch in this system for the lift pump?

Any help would be appreciated.

I read the 4th post about the lift pump and circuts problem.
It's kinda like mine.

How would you check the injector pump or that system.

I'm a marine mechanic and have tools just not the knowledge on diesels.

Thanks

 

MORE INFO,

I've jumped the lift pump and the filter is full and the drain has lots of fuel coming out.

I turn the key and it runs for a second then dies.
The injectors have fuel leaking out when I loosen the cap nut as I turn it over.(I bled the lines)

Sounds like a sensor or pressure switch or something not allowing the motor to run??

 

Sounds like the OPS (oil pressure switch) use only A/CDelco parts store ops are junk.

 

Seems to be FIXED!!!
Replaced the ops and it's running!!
When I bought the truck a year ago.
The guy said to look out for that problem.
He even included a new one and a socket.

I replaced it and it ran for a short time.
Then stalled again.
I'm guessing it was the wrong sender??
Or a cheapo. It was from Auto Zone.
The new is from Napa.

THANKS for all the help.

I repair boats and motors , if anyone needs any help?? ASK

 

You may want to go to the dealership and pick one up and have a spare I got one they are less than $30 and Google ops mod for the 6.5 I have the stuff to do it but have yet to get my lazy butt around to doing it.

 

Did it again??

 

Put in a new ops.
Runs!!
Why would it go bad so soon?

Something in the system to make it do that?

Is there any way to jump the plug the next time it goes?

I'm gonna carry a new one now.

The place the switch was plugged in was way deep down in the back of the motor.
Would it hurt to extend the brass tubing to make it easier to get to??

 

Did you put a A/CDelco in this time ? If not you should have. Parts store brands are inferior to original equipment I know they look the same but they aren't.

 

And look here there is a ops mod that you can do to prevent this from happening do not drive around with the lp jumped if you have an wreck and a fire you will feed the fire until the battery is dead.

 

The Not sure where the ops was bought that was on the truck???
Very possible A.Z. or Advance.
There was a new one(a.z.) along with a socket in the glove box.
The PO told me about them going bad.
I replaced the original a while back.
I used the one in the glove box (from A.Z.)
It worked for a week but was giving me the wrong reading on the OP gauge.
It went bad after about a week.
Replaced it with one from Napa.
That lasted less than 1 day.
Had to get another from Napa as the dealer was closed.
I bought a spare from O'Reilly's .
Gonna buy 2 from GM dealer on Monday.
The dealer is 25mi from me and at the time I had no way of getting their parts.
The place that might carry the OEM parts is on vacation.
Then take back all three of the bad and good cheapo's

I bought 1/4in brass tubing 4 pieces and made an L shaped extension.
I had/have a high pressure hose I could have used but thought the OPS might need a ground???
Doesn't leak and it seems to be about the same as what's on other 6.5's