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stalling

Jerryjerry05

Jerryjerry05

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Messages
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Location
Florida
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.
 
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??
 
Normally i say start by putting in your spare pmd to verify its not freaking out. If you have one, try it.

Oil pressure sensor (middle of the valley)sends power to the lift pump(LP). You might also have a line blockage.

Start with a small fuel can of diesel and run some fuel line from the tank to the input of the Injector Pump (IP) bypassing lift pump.

The Engine should run with the IP drawing in enough fuel to idle and rev up under no laod. If that works, chase the fuel system, new filter including tiny screen under filter, remove LP make sure fuel flows good from tank to it (air pressure in tank- 10psi) to push fuel through line. Then from LP location to FFM.
 
The tank should have pressure in it?

The lift pump has good pressure.
I open the filter and lots of fuel leaks out.
The tiny petcock? Same there.
Gonna try the ops in the am.
Thanks.
 
No, im saying if you apply pressure into the fuel tank the fuel should flow well as a test. Sometimes leaves, rust, etc will plug tank or lines.

You said LP has good pressure, what is the pressure on line coming out of FFM going into IP? If your getting good pressure after FFM disregard pressurizing tank test.
 
On the 95 the LP doesn't run until there is oil pressure. You can test the LP by putting the trans. in gear, engine off, then turn the ign. to start. You should hear the LP run, and test for flow.

I would also clean the fuse spades on the FSOS (fuel shut off sol.) fuse in the under hood fuse block.
 
Without more details as to upgrades/modifications to your motor, I'm inclined to say your PMD is fried.
 
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
 
Glad you got it.

As the previous owner learned, and now you- the load of the LP is too much for the ops. GM just messed up. You need build yourself or buy the ops relay harness.
http://leroydiesel.com/products/

While your there if you dont have your spare pmd, he sells them, I suggest getting one of his lifetime warranty. Run it, keeping your old as the spare. Then when the new one dies (they all die) you switch to your old one and send him the other to get swapped out. I tell everyone a spare pmd is like a spare tire. You need it worst when you dont have it.

Also take the time and do a ton of reading here in the 6.5 areas- it will save you a ton of $ of the next years you own it.
 
What would getting the relay harness help??

When I first got the burb I did a whole lot of reading and working.
Po had replaced one head and not the other.
I did the head and the radiator, fan and injectors and lots more.
 
Exactly. All the current to run the lift pump flows through the contact points inside the OPS. A designed failure that was corrected in later model years. If a dead OPS kills your lift pump, then your IP is trying to suck fuel all the way from the tank with its tiny draw. This, if left uncorrected, will kill your IP in fairly short order. Then you're doubly screwed.
 
Also LP relay harness might get you a pound or 2 extra PSI. It helps LP live longer too, pump better. The LP on the stock harness is like you trying the breathe through a garden hose just not not enough volume. The LP needs more volume (current) to do its job properly.
The LP draws as much as it can witch burns up the OPS then the LP dies quickly too. 9 months to a year is not uncommon on stock system.
 
Then next the IP suck fuel best it can through the dead or dying Lp and puts more load on the IP and wears it out sooner. Which also wears out the pmd faster.

In other words lack of gm spending like $100ish more per truck to build a proper system, we all burn up thousands of $ worth of parts time and again. Not to mention break down time, etc.
 
Hi Jerry I got an order from a Jerry today in Indiana I see your in FL though.. Was that you? I ask because they ordered Walbro FRB5. Your truck really needs the FRC10.
 
I have a relay already in the system.
It's in the fuse panel/box under the hood??
Or does this help in another way?
 
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