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The ground setup on these rigs is not very well designed.
With age they get worse.
As long as the PCM grounds and the heavy black ground are connected to the engine it will run, even with no lift pump.
The Lift Pump is grounded to the frame somewhere between the LP and the fuel tank.
Most of the cab electrical is grounded to the cab just above the DLC connector on the lower dash brace tube.
Run a 10ga. wire from that ground bolt above the DLC to the engine.
Run a 10ga. wire from the LP ground bolt to the engine.
I do not think grounds are your problem, but those 2 added grounds will make sure they are not.
The photo is the 95-96 OEM grounds at the pass. head rear.
There should be no ground wires attached to the starter, but would not be a problem.
If the engine will run for 10 minutes then the GPR is not the problem although shorts in the wiring to it could cause the engine to stop running.
Is air collecting in the FFM or do you mean the injection lines have no fuel?
Have you had the intake manifold off for any reason?

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Find the 2 PCM grounds, the TAN/WHT and BLK/WHT and make sure they are bolted down.
I do not see them in your photos.
Those 3 ring terms may not be on the same stud or bolt.
 
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FSO on these is redundant and for over-rev shutdown.
PCM controls injection.
 
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It will run without the airbag ground but the other 3 wires are necessary.
 
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This may help a little.

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That is them. They should be with the other grounds.
They are either bolted down somewhere out of sight or they were left off
at some point, happens quite often. If they are touching ground the engine
will/may start but will be erratic.
 

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Try to gently pull the TAN & BLACK wires up through the loom.
If they stop then you can maneuver those 2 wires into the split
in the loom and try to separate them out.
They run down towards the starter with the solenoid wire (PPL)
and the glow plug wires (ORN & LT BLU). They should be just out of site.
Look at the photo I posted of the main harness.
There is a shield down there the wires run behind that protects the
wires which along with the Burb heater hoses makes it difficult to even
see down there.
 

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If all else fails and you cannot find where they are
you could cut them and add a ring term and bolt them
down with the other grounds, where they should be.
They are connected together on 1 ring term.
Those 2 wires have caused lots of grief for many poor souls.
 

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Those are the PCM ground wires and could cause all kinds of problems if there is an intermittent connection.
I would pull on them together since they are on 1 ring terminal, hopefully.
I have never experienced or read of what your WTS lamp is doing.
The WTS lamp is lit by the 12v. going to the glow plugs.
If the glows are glowing the WTS lamp is lit.
The GLOW fuse is there to protect the gauge cluster and PCM from that voltage.
I'm guessing that wiring mess at the GPR is at least part of the problem.
 
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Here you go.

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Was the ground hanging loose, not bolted down?
 

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Do you have a voltmeter or even a 12v. test light?
 

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Just get one like in the link at your local parts house or harbor freight.
Your problem is more than likely electrical and you need to find it.
First thing to do is get the glow plug problem sorted out, you need a test light or voltmeter.
Also, it would be VERY helpful to read the codes. Your 95 OBD1 can do that with a paperclip.
Instructions are here on the site, maybe OK can direct you.
My 99 truck's original starter, 206K miles, just started acting up yesterday, (perfect timing of course) and
I'm in the middle of replacing it.

 
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Pink wire on PMD is 12v. IGN from the FUEL/SOL fuse,
also feeds the FSO. Only those 2 things.
 

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FSO = fuel shutoff solenoid, the one you gutted.
FUEL/SOL FUSE is in the UnderHood Fuse Relay Center, small fuse.
There are 2 large fuses in the UHFRC that are marked IGN A & IGN B.
With key ON, when you do NOT have 12v. to the pink wire do both those fuses have 12v?

My starter is now in and it's popping off like it should again.
 
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UHFRC

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This is what it looks like with the bottom removed.
The heavy gauge pink wire in the center of the photo is where your problem is.
The feed circuits are 3-gang terminals.
The bottom has catches around the perimeter you release to remove it.
Post a photo when you get it apart.
I have almost all the parts to repair or build new the UHFRC if you need anything.

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All the 95-up GMT-400's, gasser and diesel, and some others use the same UHFRC (under hood fuse relay center - per GM)
I've had the parts for quite awhile, I'm sure they are scarce now.
I build harnesses for the 6.5 diesels, exclusively, so I have 98% of the parts these rigs use.
The easiest way for ya'll may be to snag a few from a u-pull-it.
At a minimum remove the firewall conn. (C100) and cut the harness about the center of the firewall.
If it is a DIESEL try to get the whole harness, it will remove without cutting any wires.
Then you can remove & replace any damaged wires you need already terminated, especially the heavy gauge stuff.
 

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You can get the UHFRC loose and turned upside down, but you cannot remove it from the harness
unless you take it completely apart, not recommended.
Be sure to remove both battery positive cables before working on the UHFRC.
 
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