Is the Grey wire only hot when the switch is on?

 

yes that the wire from the OPS

 

Does the oil pressure gage still work?

 

yes gauge still all you doing is setting it like 97+ where LP will run of the relay instead OPS but it still be set up if happen to roll over the truck the OPS will shut off the LP yes there are easy ways of doing but not safe

 

the OPS contacts are not heavy enough to run a load. they will all fail when used to run a pump. I have always ran a pump with relays designed for load. Thanks for the help.
If it is not to cold out I will do the fix Monday. I still may have a Turbo problem and I got to move that black box on the Injector pump..

 

Hi Ed or anyone who might know. Did you get this problem fixed?
I'm having the same problem. It seems significant that I can turn the truck off for 10-20 seconds and the problem goes away, then it comes back again in a few minutes. It seems like heat might be triggering the problem except that I wouldn't expect that the heat dissipates so quickly.

Putting the truck in neutral doesn't fix anything, but putting the truck in neutral and turning the ignition off while I coast on the road, seems to fix it temporarily. This, of course, is dangerous since the truck has power steering and power brakes.

Mostly what I do is pull over, turn the truck off and wait a few minutes. The longer I wait, the longer the "fix" works.

The truck runs great for the first 30-40 miles then it progressively gets worse. Used to run about 100 miles before having this problem. It all started about 6 months ago. Before that it ran great, even took it on a 3000 mile trip 2 years ago.

 

I have a 1996 6.5 t.d with the exact same problem! I actually parked it 6 months ago after putting a new lift pump in it and injection pump! It didn't fix my problem and I was tapped out and frustrated! History of truck. I bought it cheap with what I thought was a blown headgasket.......... yup cracked head, replaced both sides and while I was there did the glow plugs and injectors, push rods etc. Truck ran like a top. Then one night I was backed down on the boat ramp and I heard my truck stumble and watched her blow black smoke. Jumped in and barely made it up the ramp, good thing the tide was very high or I wouldn't of! Truck seemed to straighten out and I forgot about it then one day shortly after I was on the highway and she lost power hesitated and I pulled over and she was running real rough so I turned it off. Started it back up and it seemed fine for 5 minutes s then same thing. Went to my shop thinking it was electrical at first so I bought a crankshaft sensor from AutoZone only place open and put it in and it didn't start so I put the old one back in and it started took it for a ride and same thing happened. Lift pump was working but I put a new one in anyways and put my brand new back up and in and same problem still. Changed fuel filter put a number 5 resister in and took the 9 out no different so I figured gotta be the injection pump....... new one and still same problem so instead of driving it off a cliff I parked it and bought a gmc 5.7!!! So the truck is sitting. I have a tech one machine but the truck will not throw a code! I have been thinking it's a clogged fuel sock and soon was planning on dropping the tank but came across this thread and man I am praying someone knows the cause and fix because I'm desperate! Very mechanically inclined but diesels not so much but after this truck I feel like I'm becoming some what k owlegable about the 6.5!!! HELP

 

Welcome to DB you might want to start a new thread this one is a few years old, first thing you want to do is remove that CPS and dig a hole in the ground about 6 ft deep and bury it in the hopes it's never seen again seriously only use AC/ Delco parts for these trucks a few more dollars will save you tons of headaches and heart aches down the road.