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94 6.5 diesel K3500 died going down the road. Will not restart. It died like it was

This is the small ground wire
 

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It been awile so going of memory, but I beleive that ground is for the ECM. Without it the engine will shut off just like you turned the key off.
It looks pretty bad, I'd clean all that up real well. Remove the wire and clean some more.
 
Grounds are done. Took everything apart, used Kopper koat, cut that wire off a little, put it on the other stud with the other 2 grounds and ran a ground from the battery to that stud also. Now, even if the stud loses ground to the block, it is still grounded. Something I do on all of my vehicles.

Next step is diagnostics

Tanman, I might well be interested in that ECM

Looks like I could use new wiring harnesses under the intake. Everything except the short piece that goes to the PMD.

It still had the OS filter on it. IT has now been removed and plugged directly into the pump. That was when I noticed the OS harness was pretty brittle along with most everything else under there

Does anybody have a source for harnesses? Part numbers? Anything?
 
jrsavoie said:
Grounds are done. Took everything apart, used Kopper koat, cut that wire off a little, put it on the other stud with the other 2 grounds and ran a ground from the battery to that stud also. Now, even if the stud loses ground to the block, it is still grounded. Something I do on all of my vehicles.

Next step is diagnostics

Tanman, I might well be interested in that ECM

Looks like I could use new wiring harnesses under the intake. Everything except the short piece that goes to the PMD.

It still had the OS filter on it. IT has now been removed and plugged directly into the pump. That was when I noticed the OS harness was pretty brittle along with most everything else under there

Does anybody have a source for harnesses? Part numbers? Anything?
Click to expand...

I can pull it out of Ol' Blue. It is a stock 5068 HO IP truck. If you pay shipping there and back you are welcome to use it for diagnosis and to get around on until you get something more permanent. The truck wont be moving far awhile anyways so if that will help you then have at it.
 
The fuel control on my DS4 just went crazy r&r ip last week though it was optic but after I tore old ip down I found some trouble in the fuel control the part of ip the wires bolt to under the black rubber cone looking thing
 
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Dont know what I found just yet though I bought a new ds4 from my stanadyne vender in missouri mine would not idle right bout 1200 vs norm7-800 rpm and when I did step on it it was slow to return to idle I ran a 10ga wire to my batt from the stud at rear of engine when my truck was new I dont trust fender gd either and I even changed my apps peddel before I ordered new ip but mine would start back after stall wo pmd change
 
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tanman_2006 said:
I can pull it out of Ol' Blue. It is a stock 5068 HO IP truck. If you pay shipping there and back you are welcome to use it for diagnosis and to get around on until you get something more permanent. The truck wont be moving far awhile anyways so if that will help you then have at it.
Click to expand...

I'll get some more diagnostics done and let you know.

Thanks

It's much appreciated
 
jrsavoie said:
Grounds are done. Took everything apart, used Kopper koat, cut that wire off a little, put it on the other stud with the other 2 grounds and ran a ground from the battery to that stud also. Now, even if the stud loses ground to the block, it is still grounded. Something I do on all of my vehicles.

Next step is diagnostics

Tanman, I might well be interested in that ECM

Looks like I could use new wiring harnesses under the intake. Everything except the short piece that goes to the PMD.

It still had the OS filter on it. IT has now been removed and plugged directly into the pump. That was when I noticed the OS harness was pretty brittle along with most everything else under there

Does anybody have a source for harnesses? Part numbers? Anything?
Click to expand...
I got new pump harness from ssdiesel other day delphi brand oem quality I think delphi used to be delco I know thay own cav Lucas and stanadyne now seen a harness that goes under lntake on ebay used went for bout 200$ best I recall
 
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jrsavoie said:
Are there any fuses on a 1994 that are not in the fuse box under the dash other than the lift pump fuse on the firewall?
Click to expand...

On my 94 I did find one fuse, in the cab, under the dash, buried in the wire loom just above the convenience center (between the E-brake and the steering column). But it is for the power windows if my memory is working.

Don
 
The pump&filter harness is one on ebay now 69.00 buy it now price search gm 6.5 pump&filter harness I was at gmc dealership in 94-95 as the diesel tech and I replaced alot of ecm and pumps the green tag on a pump was a sign of a warranty pump but I cant recall if the ecm had a tag or mark to tell u if it was a warranty job we had so much trouble w ip&pmd issues thay had a tag to let another service dept know what had been replaced im looking through my 94 diesel supplement manual at my notes but havent come up with any thing you havent alredy tryed yet
 
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From what I understand the filter harness is not necessary, nor desirable. So my plan is to just eliminate the filter harness. I need anew optic sensor harness and what ever other harnesses are easy to change while I'm there. I have the harness that you plug the PMD into.

Any links or part numbers or anything relating to any harnesses I need would be greatly appreciated.

Thank you much.
 
How much fuel should be coming out the return line?

I have the plunger off the fuel shut off solenoid.

With the lift pump running there is just a tiny trickle.

When trying to start it puts out just a little more.

With the return barb and adapter out of the IP - eliminating the small orfices. It seems the same amount of fuel is coming out the return hole.

If there is not enough fuel coming out the return, are there other possible causes - electrical - other than the Injection Pump?

Or is what we are seeing just normal?

It seems the last time I checked the return line there was better flow. But it has been a while since I did that.
 
Seems like there should be alot more fuel than a trickle. Have you tried jumping the lift pump fuse on the firewall and then cranking? Had a 93 that would not start unless the lift pump was jumped. I tried everything. Killed a set of batteries. Never did find the exact cause because it was a parts truck but as long as I hooked the jumper wire up first she started up without to much fuss.
 
The jumper wire haS BEEN HOOKED UP ever since I started working on the truck.

I even tried my 2 spare lift pumps. Though the way the truck dies I din't think it was a lift pump issue.

Had the return off the 98 Suburban last night, to see how the flow looked in comparison to the truck. The Suburban was putting out a good stream of fuel out the return port when it was running.

Not so much with the lift pump running and the Fuel shut off solenoid open. So I didn't learn a lot by checking the Suburban to compare it to the truck. When the truck is cranking it will spurt fuel, which leads me to believe that this may be normal.

More diagnostics to be done. But the list is getting shorter
 
Thanks

I am not getting any fuel to the injectors.

I tried to start with the Crank position sensor unhooked

I checked the pins on the cable That comes from the engine and feeds the PMD
Pin A had 1.65 to 1.75 volts while cranking
Pin E had 0 volts
Pin C had continuity to ground - .02 ohms or so
Pins B & F had no continuity

Any ideas?
 
By a previous post I did not understand that the pins were in alphabetical order across the plug. I also Could not see well enough to know the plugs were labeled with the pin configuration. Actually only about half the plugs I have are labeled.
Turned out I had a pin that was not making good connection. When I tested each pin they all read correctly. When I tested at the end of the extension harness I found an inconsistency.
It actually worked with a different harness that seemed to fit together tighter
When I have nicer weather, I need to replace the PMD/ injector pump harness.
Thank you much
 
Thats good, but sucks it took so long for a simple problem. In your 1st post you said you tried a new ext cable, so I never even thought it would be the problem.
So you have two bad cables?
 
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