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Discussion Starter · #1 ·
Hi All,

1995 6.5 Diesel safari trek
I'm trying to sort my no fuel and no glow plug issue.

I only have 4.5 v coming into the OPS and the fuel pump relay.
I'm assuming they should be 12v

Earth issue maybe? Where is the fuel pump relay earthed?

thanks

Mark
 

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Welcome to DieselPlace
(y)
 

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Discussion Starter · #3 ·
Hey thanks.

Shouldve written this first.
I have a Safari Trek 6.5l Diesel 1995
I've had the top off and upon reassembly find that I have no glow plugs or fuel.
I have no clicking relays either.
These all worked before head off.

I have power to the glow plug relay(red wire) and from ignition on the pink wire. I have no signal from the yellow wire.

The fuel pump works when I by pass the relay and is providing good flow.

Maybe something wasn't reconnected during reasembly? It beats me!

Any help appreciated.

Mark
 

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Look for ground wires that were bolted to the engine.
They are usually at the rear of the engine head.
There is very little info on the Safari Trek 6.5l Diesel
so you just have to track things down.
 
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1997 GMC K3500 dually 4L80 4x4
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There are two ground wires that bolt on with the intake manifold on the right rear of my truck. I can send a picture if you can't find the grounds
 

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Discussion Starter · #8 ·
There are two ground wires that bolt on with the intake manifold on the right rear of my truck. I can send a picture if you can't find the grounds
Thanks, I'll have a look tomorrow.
Where do these wires originate from? Pictures would be great. If you have the time , that is.

Mark
 

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Thanks, I'll have a look tomorrow.
Where do these wires originate from? Pictures would be great. If you have the time , that is.

Mark
Links for grounds and more can be found in our 6.5L FAQ page listed at the top of this forum section.
(y)
 
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Discussion Starter · #10 ·
Thanks for these pics. I had reseated the Battery Earth and Engine earth strap. PCM Earth good too. Will chase down the others today.
Mark
 

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1995 GMC Suburban
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On a regular truck in 95 model year, the OPS controls the LP when engine is running.
Mind you, the gauge will still work but the LP is not if the OPS is bad.
Sounds like the LP is working but it may not pump when engine is running which point to OPS.
 

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Discussion Starter · #12 ·
I think I've tracked it to low voltage coming into the fuel pump relay. Only showing 4V. Must have a short, I'm guessing. Any ideas?
 

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I think I've tracked it to low voltage coming into the fuel pump relay. Only showing 4V. Must have a short, I'm guessing. Any ideas?
Trace the wires from the lift pump back up looking for any rub through wire insulation issues, rodent damage, etc.
Also, try disconnecting the fuel heater wires located on the bottom of the fuel filter manager.
The heater element is known to short out
 

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1997 GMC K3500 dually 4L80 4x4
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Is the 4 volts on the contact pin? or the coil pin? The coil power is from the crank fuse, contact power is from ecm b fuse.
 

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1995 GMC Suburban
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On a 95, the relay was not wired correctly, for some reason.
However, I have never diagnose it, in terms of how much voltage should come out.

Did you measure it when engine is running?
 

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Discussion Starter · #16 ·
Trace the wires from the lift pump back up looking for any rub through wire insulation issues, rodent damage, etc.
Also, try disconnecting the fuel heater wires located on the bottom of the fuel filter manager.
The heater element is known to short out
I'm not sure mine has a fuel heater? 1996? Safari trek?I'll have a look. Checking that wire now for rubbing etc. Maybe I'll run anoter wire up to the fuse board.
 

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I'm not sure mine has a fuel heater? 1996? Safari trek?I'll have a look. Checking that wire now for rubbing etc. Maybe I'll run anoter wire up to the fuse board.
Located on the very bottom of your fuel filter manager is the fuel heater. The black canister contains the heater element.
You'll see the wire connector for it.
 

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Discussion Starter · #18 ·
On a 95, the relay was not wired correctly, for some reason.
However, I have never diagnose it, in terms of how much voltage should come out.

Did you measure it when engine is running?
Located on the very bottom of your fuel filter manager is the fuel heater. The black canister contains the heater element.
You'll see the wire connector for it.
Ah yes , Found it. Wires seem fine. disconnected it. No change
 

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Ah yes , Found it. Wires seem fine. disconnected it. No change
The Oil Pressure Sensor (OPS) feeds power to the lift pump. Over time the Sensor becomes weak and brittle and the contacts inside can no longer support the power needs of the lift pump..
I would replace the OPS next ( Use only AC/Delco brand )
 

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Ronald Reagan fan
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X2 on using acdelco whenever possible .👍
 
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