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Won't go over 30Mph

Chevy6.5TD

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Location
Rotterdam, Ny
I have a 96 2500HD with the 6.5 TD. Just bought it. Ran fine when I drove it home. Next day would not go over 30Mph. Test and parts replaced:
1. Tested lift pump no fule from test valve did not die. (you can here LP before start)
2. Replaced fuel filter and retested and did some times.
3. Checked voltage to ops while runing ~13 (no load)
4. Replaced LP and tested LP fuel came out and did not die.
5. Drove truck and worked ok for a 3 miles then can't go over 30mph
6. Tested lift pump tested bad engine died.

I know it is a 96 so obd II so don't need OPS for working pump? Does the other relay ever go bad or get week? Can I have bad OPS and other relay? Where is othe other relay?

Thanks
 
the other fuel pump relay is in the underhood power center. Did I read right that you opened the drain t and did not get fuel but the engine kept running? Are you sure the drain hose isn't plugged?
 
The filter was plugged and I replaced the filter and the the truck died during the test. Then I replace the pump which worked for a little while but not to long.
 
check the grounds to the relay and the lift pump.all the grounds for that matter.
the relay could be bad but thats a bit more rare.
 
Sounds like clogged tank sock?

Do you have vacuum when you open the fuel cap?

Check all the grounds, electrical connections and cables.

This just happened to my Dad's suburban, turns out the connector from OPS to the LP down under was not tight due to dirt.
May be worth checking that.
 
It was a vacuum leek in the fuel line going to the lift pump.

I wired the pump so it is on all of the time that didn't work so I was going to drop the tank (maybe clogged sock).

While look at what to disconnect to drop the tank I left the truck running and pushed on the place where the steel fuel line goes into rubber. The truck died. I put some caulking on it and that helped so I ordered nylon replacement lines and now it works.

Well it worked except I did not tighten the air vent on the filter enough and when done testing it it had lots of air in it.

Thanks for all of the help.
 
I was wrong it is not fixed. The lines helped or the shacking the tank around helped. I took the tank off again and opened it up. There is a layer of white stuff at the bottom of the tank. The tank is almost new. Should I get another one or clean this one out? What should I do with the fuel inside?

Is the sock(fuel strainer) in the tank the same as the one for gasoline engines? The parts stores don't carry one for this truck.

Thanks
Aaron
 
I would just clean the tank and eliminate the sock. Put an external filter on it, like those cheap clear ones you can put inline or a more elaborate Racor setup. It is not the same pickup as the gassers. Maybe empty the fuel through a strainer/paper filter? part of the reason its a closed system is to keep stuff from growing in there.
 
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