• 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!

help, husband wants to sell it if we can't fix it

J

jprice

New Member
Messages
15
Reaction score
0
Location
Alabam
okay hello you all, I need some serious help. I have a wonderful 96 diesel 2500 sub. I love it it fits us perfectly but has had some interesting issues lately... I am attaching the check list and am filling it out the best I can, i need some help, I do not want to want to sell this truck!

Okay so the truck will be running just find and will stall out of no where it will it usually recranks and runs but occassionally you will put the key in and it won't make a sound. The glow plug light won't come on and it is quiet. My husband has tried removing the batery cable (neg on both sides) and allowing the computer to reset, we hook the cables back up and after a few minutes of them being hooked up it cranks. We haven't done this to know if it is just a chance cranking or if removing the cables actually help it out... This is variable, it seems electrical but hubby is frustrated and not sure what to do next... HELP PLEASE!

1. Does the engine crank, or 'turn over'? yes when it isn't having a problem, quiet when it is having and"issue"
1a. Does the engine start and run? beautifully when it does turn over
1a1. If the engine does not start - Crack injector line: do you have fuel? Yes
1b. Do you have a Wait To Start Light & the amount of time (seconds) lit. No
1c. Ambient Condition (temperature outside indicate F or C) ?50 F
1d. Engine Cranking speed (if you have an accurate tachometer). ?
1e. Are you experiencing stalling? Yes
1f. If Stalling, describe (upon startup only, down the road, hit a bump etc) hmm, about 5 minutes after start up
1g. If Stalling, do you notice loss of dash or instruments? not sure
-note if experiencing stalling,you must indicate PMD location in #24.

1h. Check turbo inlet and air filter for obstructions. Cone filters have lost disk and stopped air to turbo.
1i. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now? yes/no
1.1 Lift pump test - describe results
2. Service Engine Light while running?- off
2a. Service Engine light does glow during start/cranking/bulb check: Yes, but not sure if when the wait to start light isn't coming on if it isn't coming on also
3. Model year 1996
3a. Odometer reading (indicate if in miles or km) 120,000
3b. Miles on major engine components if been replaced (example Injection pump)
3c. Indicate the model number on the Injection pump (starts DS4 or DB2......)
4. Have you scanned for engine codes? (varies by pre/post 96) no
5. List exact results on engine codes:
6. Air Filter condition (visual check) fine
7. Fuel filter condition (freshly changed/condition unknown/mileage since changed) changed within the year
8. Condition of Battery terminal connections (removed, cleaned and tightened) cleaned and tightened
8a. Known condition and age of the batteries. bought withing the last 6 months
8b. Are batteries of differing age or are they a matched set? matching
8c. Condition of Major Grounds. (same drill as batt - removed, cleaned, retightened) not sure
9. Upon cold start, does the radiator hose get hard quickly?
10. Upon cold start, do you have excessive white smoke? smoke yes not a lot
11. Do you have excessive cranking time before the engine starts? no
12. Have you used the block heater, and does this effect engine starting?(only try for starting problems) haven't tried it
13. During hard acceleration, do you have excessive black smoke? no
14. Do you have any unusual exhaust smoke issues? no
15. Turbo check out - ?
16. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit) ?
17. Indicate if you know if it’s a 2500
18. Indicate fuel that you are using: Diesel
18a. If running a VO (Veggie Oil fuel) setup, indicate details of your conversion (homemade, or packaged system)
19. Are you using any fuel additives? If so, please list. none
20. Please indicate geographic region you are in: Alabama
21. Do you have any service history available that might pertain to the problem you are having? have replaced OPS, PMD
22. Please indicate any modifications to the vehicle that might help us diagnose better.
23. Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? yes
24. Location of PMD/FSD? On the pump/remoted over intake/remoted out of engine bay on a heat sinc (?) and attached to where the turbo cover is, thinking about moving it
24a. If remote mounted, describe wiring harness (homemade or purchased from a vendor?)
24b. Indicate the location and condition of the FSD/IP grounding wire.
25. Are ALL glow plugs in proper working order as per this thread yes
 
First of all welcome to the group. This will come up so let me get it over with. You need to click on the user cp link on upper left hand side of the page and then in the left column there will be a signature link where you can add pertinant info like I have below. Year, make, model, modifications, etc.

From what I see on your check list. Your PMD/FSD is mounted on heat sink in the engine compartment. If that isn't correct let us know. The stock location for them is on the injection pump. The PMD/FSD is a computer and the heat of the engine compartment will fry it rather quickly. Most of us have them mounted on heat sink outside the engine compartment. Mine is behind my licence plate inside the front bumper. If I had to guess I would say your PMD is fried. You can find a new dipacto for just under $200 shipped. Even if the problem isn't your pmd you will want a spare just incase.

Next you need to do a lift pump test. There is a t valve on the front left of the motor that if you twist it open and turn the key to the on position it should shoot fuel through. If your truck is running and you open it and the truck stalls it is an indication that the lift pump is bad or the ops is bad. Hope this helps.
 
By the reconnect the batter and it starts for a while, check this:

The next time you remove the battey cables, remove the bolts and puck from all 5 battery cable terminals.

Look for corrosion under the bolts and puck on the cross over cable. Moving the cables with make a connection for a while but then cause issues.

I had issues last year when the truck wouldn't start. Cleaned every thing and applied anti corrosion grease, this is a year later: (note the anti corrosion grease and the copper color inside the terminal covers)
attachment.php
 

Attachments

  • IMG_0235.jpg
    IMG_0235.jpg
    92.6 KB · Views: 311
Battery connections and ground connections are key, it doesn't take much to get a no crank situation if there is corrosion, but that shouldn't make it die once started. As you have no power at all when it dies, and no cranking, my suggestions would be the ignition switch. Seems that your truck has fairly low miles, so this is unlikely, but worth checking. If it is PMD, it will usually die randomly, but still crank. Others will have other ideas for you too, but start with the simple things. Hope that helps.
 
I have to agree with most of the answers you have gotten so far. The 6.5 needs good clean connections to eliminate electrical issues first. Need to remove clean and replace all grounds. Not only the battery connections but also the grounds at the back of the engine for the wiring harness. There is also a ground connection to the firewall on passenger’s side and then a ground strap to the frame on the passenger’s side frame rail. I used a dremel tool and wire brush to get all the surfaces shiny clean and then applied die-electric grease to help keep them that way.

On another note the ignition switch is a known problem. With you having problems with the dash indicator lights it is a good possibility that it may not be working properly (intermittent). It is not the key cylinder but the electrical ignition switch.
 
Dont fear. With this site and all the help of the great 6.5TD crowd you will have your Suburban up and running in no time.
 
Remove the negative battery cables.
Clean the negative battery cable connectors and battery terminals - Leave the wires off for now.
Trace out the grounds - One at a time - Remove, Clean, (optional dielectric grease - good idea), clean up the connection point, put them back nice & tight. There's a strap from the top of the block to the frame, near the starter. DO NOT miss this one! Make sure the strap is OK - Not corroded or broken.
Remove the positive battery cables - You know the drill. Replace them nice & tight.
Make sure the starter wires are tight. Be sure starter bolts are torqued to spec. Be absolutely sure the bracket from the starter to the block is in place and hardware is tight.
Replace the negative battery cables.

Even if this doesn't solve your problem you will have a solid place to start from. These are common problems and definately could be related to your problem.
Cleaning is best done with a Dremel & wire brush or crocus cloth.

When you go to start the truck up after the above, the Glow Plugs (or Wait To Start) Light will cycle VERY short. Crank for a few seconds and turn the key off. Glows should cycle normally. If they don't; Turn the key off and on a few times till you get a normal glow cycle.
 
Don't neglect the suggested wiring procedures: the PCM is a computer - imagine how your PC\laptop would run with wiring\grounds in that bad shape - those are a yearly inspection requirement, each winter, in a 12yr old vehicle.

Also, as suggested, the ignition switch is problematical, giving the indicated symptoms - at well over 12yrs old, time for a replacement

Then, due to same decrepitessness, do the FSD\PMD upgrade, preferably the Heath flavor - restores reliability and confidence in the old cow - don't leave home without it.................
 
gmctd

YU... can`t call her an Old Cow she`s, just started going though puberty.. pour thing,,, if only ...we could have an understanding...



gmctd said:
Don't neglect the suggested wiring procedures: the PCM is a computer - imagine how your PC\laptop would run with wiring\grounds in that bad shape - those are a yearly inspection requirement, each winter, in a 12yr old vehicle.

Also, as suggested, the ignition switch is problematical, giving the indicated symptoms - at well over 12yrs old, time for a replacement

Then, due to same decrepitessness, do the FSD\PMD upgrade, preferably the Heath flavor - restores reliability and confidence in the old cow - don't leave home without it.................
Click to expand...
 
I had similar problems. Combination of ground and FUSE problems. Pull all fuses (one at a time) out of fuse box in engine bay, clean all fuse connector legs with a rotary power tool with wire brush. Use DeOx agent on the sockets, and clean clean clean!

Problems with the FUSES will mimic ignition switch problems. I know. I replaced the ignition switch (expensive!) and still had the problems UNTIL I cleaned the fuses and fixed the grounds.

-Rob
 
What about the idea of selling the husband?

sorry, could not resist ):h

That being said, when this happen, I mean no sound, no light, try to wiggle the harness under the steering column, this harness is connected to the ignition switch - not talking about the key switch- another one hidden.
If the truck comes back to life, and if you can reproduce the issue doing so, there's a good chance you need to change this harness with ignition switch.
 
I vote Ign switch also. Pull the cover off the bottom of the steerin collumn, find the plug going to the ign switch, when its running right take a test light and find all the wires that have power(mark them). Leave cover off for now. The next time it stalls, make sure those wires still have power.

If you loose power to two wires check fuses. If you loose power to just one, jumper power to that wire and see if it will start. A buddy of mine drove his that way for over a year,lol, talk about theft deterent.
 
Does the cruise control work? This is a classic symptom of a bad PMD.

x2 on the grounds and fuses. Check them and clean them and the truck will be happy most of the time.

PS my wife really likes her Suburban as well :)
 
wow so much info

Thank you guys for all of the info, something someone typed jumped out (okay lots did and while I am not mechanically inclined I am pushing all this info infront of my hubby) the cruise control has been a bit touchy, not wanting to engage when you press the button and also a few weeks ago the gas guage began to go a bit crazy. Hubby suspected the computer under the glove box? I'll have him check the grounds and all that has been suggested, I hope it's not the PMD we replaced it this past summer but it looks like we should have mounted it somewhere besides where the turbo cover goes (tubo cover is off b/c of the PMD sync) any recommendations? Can we use the same sync and just remount the PMD (new one if it's needed?) and should we buy a extension wires or make them ourselves (okay really himself)

Can't sell the hubby, he's the only one who can work on this truck as we quickly found out the local dealership mech had no clue about these crazy diesel engines... did look at new trucks and can't stand them, I refuse to trade this great truck, we will all become friends very quickly! thank you so far will update soon! But will keep reading!
 
J-

The most common and arguably best location for the PMD is directly behind the front bumper. Anywhere outside of the engine compartment (and interior of the truck for that matter) is good.

You should be able to use the same heatsink, just mount it in the location mentioned. You'll want to get an extension harness. They can be had on fleabay for fairly cheap.

I think between the PMD and the grounds, we might nip this one in the bud.

Good luck.
 
Erratic cruise is definite symptom of failing PMD - quick, turn it into a FSD: getitoffa the inj pump!
FYI: the module is not water\weatherproof, as are not some of the aftermarket harnesses, so mounting it outside the engine bay is not a good idea unless all is proplerly sealed - or get the Heath waterproofed version with it's astounding warranty guarantee
 
You must log in or register to reply here.
Back
Top