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Discussion Starter · #21 ·
The vacuum lines have a plug on the other end for some reason and lead nowhere. I’m planning on fixing those if I can get it running for a bit longer and moving.

my understanding is that the PMD will shut it down from the key but worse case I’ll plug the intake with a coat or board or something.

Exhausted my batteries and daylight today trying to get fuel to the injectors again. Sad.
 

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Discussion Starter · #22 ·
Glagulator, I’ve looked for a third but don’t see one. Those are the only two I think I’ve got. Would the rest of the system be working without a PCM ground? I suppose I could trace it back from the PCM but it’s tight back there. The wiring is such a mess.
 

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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.

Font Terrestrial animal Metal Serpent Tail
 
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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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Discussion Starter · #32 ·
Interesting. It’s too tight to see where they go and extremely dirty. Do you think I should pull them, cut, put them together and extend to a new ground? They’re supposed to be touching right?

very odd.
 

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If the ring terminals are bolted down, take a voltmeter set to the mv scale and see how much voltage is present on that ground wire with the key turned turn on or in crank mode. Don't know the older gm diesels as I work the gm gas side for 30 years(so yes I'm electrical geek), I did work on the 5.7 and 6.2's. what are those grounds so I don't have to find a schematic?
 

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Is the ground wire from the pmd harness connected to the pump?
^^X2 this one is important also. Black ground wire runs from the PMD harness to the top of the IP and is held on with a Torx screw.
 

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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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Discussion Starter · #40 ·
Thank you all guys, seriously. I’m normally a good shade tree mechanic and have only met one other vehicle I couldn’t do (due to parts budget). This one is rough.

to answer questions the pump is grounded on the pump. The prior owner said it was newer and it certainly looks it. No leaking in the valley that I see (now).

with the wires, I can try to get under there and see but my guess is I won’t be able to see anything.

I kinda like the idea of tugging on the black and tan wires individually and, if they move, splice them together along with another wire to extend to an intake ground.

would this problem be causing my no start, no wait to start light?

I sincerely hate electrical. I suck at it. But for this thing I’ll try my best.
 
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