• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Couple questions on my first diesel.

M

Meatman

My other vehicle has 2 Turbos!
Messages
16
Reaction score
0
Location
Vancouver, Canada
Hello everyone....

I just bought a 94 GMC 2500 with a 6.5 TD (166K Kms), and I am going through the required maintenance when you first buy a vehicle. Such as all the filters/fluids, a new set of glow plugs (duraterms).

This is my first diesel and I have yet to buy a service manual so I am unsure on a few things.

When I replace my fuel filter (engine bay) is it as simple as it looks? Just unscrew the used filter, screw on the new one, crack the bleed valve on the top (little black part) turn the key to the on position and when the diesel starts to come out tighten the valve and that's it?

Second question is I have owned it for a few weeks and an issue has arisen where after driving it for ~1/2 hour it just dies.... however it restarts every time. Its kinda random, happens 3 X in a row then not for 1/2 hr..... then again.....very intermittent. Its kinda like when you shut the truck off by taking the key out....immediate dead... no stumble just dead.

Is this the PMD failure I have read about ( I have read for about 10 hours before I posted anything)? It is a Stanadyne PMD still located on the IP. I was told by the previous owner that the IP was replaced about 1.5 years ago (20K Kms). When the IP gets replaced does the shop usually transfer over the PMD or does the IP come with a new one?

As well I am planning on getting a remote PMD (what is the other term FMD?) with the heat sink asap.
 
Welcome

Congratulations on your purchase and welcome to the community.

You've nailed the filter replacement proceedure pretty well. Just ensure that you have a small plastic and mesh screen inside the filter before replacing with the new one and inspect the bowl for debris. Some purchase their very own Turkey Baster to remove the fuel and gunk. Others have tried using their spouses basters to negative results.

Your stalling issue could be a number of things and with a PMD still on the IP that is where many a conclusion will immediately jump too.

You need to keep gleaning the stickies for stalling issues and ensure the other issues such as grounds, fuel pressure, OPS etc (which are cheaper to address) get eliminated as the cause first. Kudo's for doing a lot of reading first, oh by the way.

Please fill out your signature block, let us know where in the world you live and utilize the diagnostic check list in your quest for the stalling cause. Post the results and the Diesel Meisters will have you running happily in short order.

Again, welcome to the site. You've just made your circle of friends quite a bit larger.
 
Odlaw said:
94 should be a electronic IP. 92-93 were the only years with mechanical pumps. IIRC Hummers ran the mechanical IP's thru 96.


On edit; Holy crap, you guys type faster than me!

We're watching this like a hawk! :)
Click to expand...
Correct.:thumbsup: We like to show off to the new guy. Welcome!!!!!!!:grouphug::confused::eek:
 
You have come to the right place, see how quick a wrong answer gets corrected! You guys impress me, I guess after this I will remember.
 
Opps. Forgot to answer the original question. Factory service manuals are available on e-bay most of the time. Worth every cent. For bleeding the fuel filter on a 94 I would take the cover off the firewall on the passenger side and unplug the fuel pump relay. Insert a jumper wire from the red wire to the gray wire. That should make the fuel pump run. Then attach a hose to the bleeder and into a container. Run pump untill no air bubbles come out. close bleeder before disconnecting jumper. The fuel pumps don't run on the older trucks untill the oil pressure switch turns them on.
 
You will have to jump the fuel pump pin to +12v on the ALDL connector under the dash to prime the fuel filter.

Maybe there is a key on prime but usually it is only in crank that the fuel pump relay turns on for older years. Then the OPS takes over.
 
94 & 95 trucks will run the lift pump if the ign is turned to start while trans is in gear for auto's.
 
NVW said:
94 & 95 trucks will run the lift pump if the ign is turned to start while trans is in gear for auto's.
Click to expand...

94 will not work like this, but 95 will. Different ignition.

In a 94, the best way to power the lift pump (LP) to check pressure or prime the lines is to remove the plastic fuse cover on passenger side engine bay firewall, to expose the fuse and relay (as bk95td said). However, instead of jumpering the relay, just unclip the fuse from its plastic holder and with the fuse installed, press the tip of it (where this is a slit) up against the battery junction post next to it. This is unique to 94 for electonic IPs (same in 92 and 93 though I think). In 95 they went to a fuse center under the hood, instead of the fuse center being only under the steering column, with LP fuse on firewall. A blown CRANK (or CRK) fuse under the steering column will prevent LP power during crank, even though the LP fuse is on the firewall.

When changing the filter, you should first run the old water/crud out of the filter manager by running the LP with the way it is before touching it. To do this open the T-valve drain on thermostat housing, and put the end of the hose in a container to catch the fuel. Run LP as described above to remove maybe 4oz of fuel. Then like others have said, I prefer to remove the fuel in there and clean the filter manager before putting the new filter in. So use a turkey baster or just soak up the fuel with rags/paper towels or whatever to clean the filter manager. Then put new filter in, being careful that it is keyed correctly, and there is no old filter gasket stuck to the filter manager. Prime the system like you originally said, power the LP as described, then turn the black knob on top of the filter to let air out (dont unscrew it a lot). I would just put some rags around the filter to soak up fuel spill.

Sounds like you need a new PMD remote mounted fast, before you get stranded. Also, normal mnx is to check fuel pressure from that fuel drain previously discussed. You can get a $15 fuel pump/vacuum gauge to connect to the end of the drain hose and power the LP to make sure you have at least 5psi.
 
Thanks for all the helpul hints and tips guys, I will try/do each and every one by Sunday and update on the results.
 
Well it rained like a monsoon here for the last few days and has no sign of letting up. So I never got a chance other than to confirm that it appears all the grounds are in-tact.

I had a hard time seeing the grounds that attach to the frame rails however I got touchy feely with them and appeared to be solid. The grounds in the engine bay are solid and the battery connections are all good.

New symptom yesterday was...... drove truck for ~ 20 min (not from a cold start slightly warm still),shut it off. Got back in about 5 min later, was idleing for about 20 seconds....turned on headlights and truck died. Started right back up and was fine for the rest of the drive (~40 min), did not stall again.

--------------------------------------------------------

1994 GMC 2500 Turbo Diesel
100% stock
166K Kms (~100K miles)
Bought Dec.6/09
Sorry thats all I know so far.
 
Last edited:
Need to be testing that Lift Pump (LP) at a minumum ASAP, as if its not working (happens a lot) you risk damaging your Injection Pump (IP), which is a high dollar repair and down a couple days at least. Also would be good idea to get a new PMD on a remote heatsink with the extension on order. Dont want the hassle of dying and coasting to side of a muddy road in a monsoon either. These are the two first things to do when purchasing a 6.5 truck you need running.

Pensacola Diesel sells low priced new PMDs. PMDcable.com has good extension cables. Need the heatsink, and a resistor to put in the PMD.

The issue you have can often require urgency before causing you much larger headaches.
 
Okay, it has finnaly stopped raining AND me found time to work on the truck.

I have the Pensacola remote PMD kit here in front of me. What is the resistor for? It has no mention of it in the instructions or the box inventory (but I have it).
 
You must log in or register to reply here.
Back
Top