73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Diesel Engine Discussion => Topic started by: Yams on October 06, 2014, 06:16:42 pm
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Hi there, I'm new here, but here goes. As the title suggests, I'm having problems with a 85 Chevy k10 6.2L Diesel, specifically the fuel pump. I'm interested in buying this truck from someone, but not unless I can fix the fuel pump issue and drive it home. He's put a little work into it and said this about testing the pump and replacing it:
"I did the bucket trick with the old pump and a new one. Both pumps moved fuel on the bench but not when bolted onto the motor. With the motor cranking you can feel the push rod moving. I also primed the pump with an external hand pump with it on the motor, that didn't help. I have primed the motor by using the return line and compressed air, no luck there either. The new pump is currently on the motor."
What do you guys think? My thoughts are that if the pump works, but isn't pumping, then it's either a blockage or a leak in the fuel line. So I was going to disconnect the fuel line leaving the pump and crank the engine, see if I get air being pushed out (if so, it would seems like a fuel line or connection is leaking air). If it's not pushing anything, then I would guess blockage in the fuel line. Test this by disconnecting the intake into the fuel pump and try to get fuel to come out either by gravity or an auxiliary fuel pump. If neither of those work out, I was thinking of just bypassing the mechanical pump and putting in an electrical one a la https://www.youtube.com/watch?v=OLDFZit_KzY
What do you guys think?
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I have the same Mr Gasket green fuel pump in the video. I use it to test run 6.2's while bypassing the fuel tank & factory fuel filter. I hook the electric pump up to a 5 gallon fuel container and run it to a spin on fuel filter, then on to the 1/4" inlet on the injector pump.
Keep in mind if you get this truck running, he may want more $$ for it. Are you buying this truck for cheap money? Is it a far (expensive) tow home? If you can buy it cheap and its close by I would think about buying it, getting it home, and getting it running at your house, not his. If you get it running in his driveway before you buy it, you loose any bargaining power.
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I think it might be easiest to just bypass the pump with the mr. gasket one... My plan is to try and agree upon a price before. he want's 2k for it (700r4 Auto Trans, NP208 t-case, Short bed, bumper ball, dual tanks, dual exhaust, pw, pb, ps, 155k miles + a tool box, four tires (30% left) and a couple miscellaneous parts. I'm thinking closer to $1500
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It's 170 miles home so towing is not preferential
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If both pumps work on the bench but not on the motor, I would think the fuel line is blocked. I don't see how bypassing the mechanical pump will help, unless you also bypass the rest of the system.
At first I was thinking it might be a clogged pick up tube in the tank, then I noticed you mentioned that it has dual tanks. Did you try switching tanks?
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That's what I'm starting to think too just after some more research. I haven't tried that (gonna try when I go...). If it is a blockage in the fuel system, how do I fix that? Just pump the tank out then fill with diesel kleen? I could test for it by replacing the intake to the fuel pump with a line that comes from a jerry can...
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A jerry can & electric pump should get it started.
I would not recommend driving it home this way.
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Like Fitz said it could be a block age in the line or tank, one problem I've ran into with those old diesels is a bent drive rod or slightly tweaked and another issue is a worn cam lobe.It feels and sounds like it's pumping but will not actuate the pump fully to get adequate pressure.
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A jerry can & electric pump should get it started.
I would not recommend driving it home this way.
I'd drive it that way
If it were gasoline you'd wanna be careful
But Diesel isn't flammable
It's combustible
I'd probably take a couple good fire extinguishers anyway
Along with a spare tire and jack and good 4 way lug wrench
Tires are probably old and dry rotted
Strap the can in the bed and zip tie new flex hose in to the engine compartments either down and under the cab or zip it to the passenger mirror and under the rear of the hood
As long as it doesn't get pinched
If there's a return line just make sure it goes back into the jerry can also
I'd say the problem is in the line
It may have dual tanks. But they share a line and switching valve
A tiny leak will cause it to suck air instead of fuel
But to see if it runs ok with no smoke or knocks and the trans works ok. Brakes work ok etc Just strap a can in and hook it up
A lot of times on old Chevys the rubber flex lines on the front brakes swell up inside and the brakes will grab and not release
You need to check all that before you
Also consider joining AAA
Free towing up to 100 miles
If its more than 100 just get em to take you 99 miles and drop it at a mall or somewhere
Have dinner and call AAA again for another 100 mile tow
BTW. When you or the seller is cranking the engine
Don't run the starter more than 10 seconds and let it rest for at least one minute
Otherwise You will burn up the starter
If you have to replace the starter DO NOT buy one at an auto parts store
Find a place that can rebuild it
The ones from auto parts stores are just used ones that have been cleaned and painted and tested
They are not rebuilt
Also of you do get on your trip and the starter just clicks
Have a helper hold the key while you smack the starter with a hammer
This will usually get it working again
Temporarily
At least a few times to keep you from being stranded
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Try putting a vacumn gauge on the inlet side of the pump,that should tell you if its working
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So I just came on here to post another discussion and noticed my old post was still up so I figured i'd reply. Ended up buying the truck. The electric fuel pump worked great... Still haven't figure out what the problem with the mechanical one was, but don't really care... Another post about the truck with a bunch of questions if you're interested: http://forum.73-87chevytrucks.com/smforum/index.php?topic=29617.0