Pre-read warning, I'm a newby, but have done a bit of homework, please help...

My '97 3500 6.5L has been really hard starting lately and sometimes when it does start it will stall after a few seconds. It will also stall after driving for a while, but that's only happened a few times. After reading a bunch of the sites, it sounds like its either a lift pump or the pmd.

From what it sounds like, you can't really test the pmd so I tried the lift pump test. I opened up that t-valve just to the front of the thermostats and had someone crank the engine while putting the pedal to the floor. No diesel came out. From what I have read, that means the lift pump is no good correct? Is there another way to check it?

Another thing, I have a couple Fords w/ the 6.0L and when I turn the key I can hear two things; the glow plugs cycling, and what seems to be a bit of a whine, which people have told me is the fuel pump priming the system. On this Chevy there is a click of the glow plugs cycling on and off, but no whine of a pump of any sort. Am I way off thinking its the lift pump?

I worry about two other things though. We've been driving through scoria and that craps gets EVERYWHERE, could some of that got in there? How would I get rid of that? The second thing, is I just replaced the fuel filter, do you have to worry a lot about getting air in the system, could that be one of the problems?

Also, does anyone know of any posts with pictures that show what and where the lift pump and pmd are?

Please help a newby. Thanks in advance,
-Phil

 

To see pictures of the lift pump, use your favorite search engine and search for "6.5L diesel lift pump AC Delco". It looks like your typical GM fuel filter of that era, but it's a lift pump. I installed one on my '86 Blazer, and yes, you can hear it run but it's not loud. Trace your fuel lines to find it, but I'd wager you'll find it on the drivers side of the frame, inboard. I've never worked on this component of my '95, but that's where the filter is for my gas '95 Suburban and '96 S10.

First things first, turn your ignition switch to on and climb under there with your test light/voltmeter to see if you're getting power to the plug. If there's power and the pump is silent, odds are very good the pump has failed.

As far as the PMD is concerned, unless someone before you has installed a kit to mount it remotely, it is located on the fuel injection pump and in general is going to take a first-timer the better part of an afternoon to deal with. If your engine isn't very clean, I'd plan on setting aside 8 hours to complete the task and would be happy when I got done early. Plan for the worst, hope for the best.

 

sound more like your oil pressure sending unit.
on the 6.5 the oil pressure sending unit controls the lift pump. if oil pressure isn't there it won't turn on the sending unit and it puts all the load on the Injection pump.
these are in the vally on the block and it gets hot there. i have to replace mine about once a year.

is the sending unit getting voltage? if not then you need to look into the oil pressure switch/sending unit.

BTW you will still read normal oil pressure in the gauge but as well as sending resistance levels (0-90 ohms) it has a cut off switch circuit that is on the grey wire.

the lift pump in usually on the inside frame drivers side. it's looks like a gold (or dirt colored if it's old 8-) ) about 3 inches long and about 1.5 inches around with 2 wires coming out of it. and a line coming in and out of the ends.

 

ObdII doesn't go thru OPS.

Lp is under drivers seat on frame rail it looks like a fuel filter with a pig tail. I believe it's a 5/8 and 3/4 wrench to take it off.

PMD is under intake manifold on right side of IP

 

I agree locate PMD it will say stanadye it will be black or grey and you would know if it has been relocated cause you will see the 6ft wiring harness that looks out of place going over fan surroud and down in front of Radiator. And These is the most common part the causes several different problems to many to list I recommend BD diesel and they are out of Canada That is closer to you but buy the whole kit with #5 resitor .Some people say use #9 but they must like replacing melted down motors not me . There is a place called Turbo,Diesel, Electric here in Atlanta thats Stocks these and much more for your truck . Also for $30.00 replace oil switch>