• 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!

Fuel Injector Pump or Driver

6

6.5TD Burb99

New Member
Messages
5
Reaction score
0
Location
SE TN
New to site. Don't really know much but thought you guys could offer some help/advice.

Just purchased a 1999 burb 6.5 TD. Went to pick it up and was having troubles starting. Left and when former owner fixed it he drove it down to us and it is now ours.

What he did to fix:
cleaned and checked all ground connection. apparently he thought this was the problem because he drove it for about 5 hours between working on it and the trip to our home.

The next day the same problem.
Checked the connections again and all was good. Tried boosting. ruled out any battery alternator problems. Called my diesel mechanic and he is way backed up right now. Took it to GMC dealership to have diagnostic ran. They say Fuel Injector Pump. Former owner thinks they are lying. (by the way he offered to come down and fix it) The former owner mounted the driver module on front of truck.

Symptoms:
When you try and start the burb it struggles a lot. Does not want to start at all. However, after several tries it eventually starts and will continue to run if the gas peddle is pushed down even just a little. Once you let off the peddle it struggles and then stalls.

Okay, so dealership says $1700 to fix. Should I trust them or check the connection between the mounted driver or maybe something else before we spend that kind of money?

Our capabilities are small but some things can be done here.

Thanks is advance.
 
Welcome !!
Never trust the dealer. Try and get ome history on the PMD. If you suspect the extension cable take the PMD and plug it in right at the manifold and eliminate the cable. Try to find out where he got he pMD from. Lot of hacks on ebay selling junk. The the IP weas bad you'd probably be blowing alot of raw fuel smoke or the thing would be bouncing all over hte place rpm wise. There is a diagnostic checklist in the sticky section of the forum. Fill that out and it will help alot. If I am undersatnd your symptoms right you cannot keep it running ? If you give it fuel for a bit until it runs for a minute or so it still stalls ?
 
I've never actually seen an injector pump go bad, lots of them replaced but I don't know what the actual percentage of unnecessary IP replacements that should have been pmd replacements...long story.
I have seen many PMD problems, even if it's a recent PMD in the right location with proper harness. The newer DiPaco style PMDs are much better.
Check out the sticky diagnostics thing and fill it in. In my experience PMDs fail while driving, shut the truck down then either will or wont restart. Starting and running for five hours would be lucky.
Always check the filter, I've solved run problems more than once with a filter change. Recently, after adding a gauge I thought my lp was bad because the filter was recent and still looked fairly clean and the fuel pressure was too low. But a new filter cleared it right up. Must have been clogged with some invisible type of crap.
Short story long, filter first, then pmd. Grounds and battery terminals next. Lift pump may be intermittently weak, but that shouldn't cause those symptoms. Few other things to check, I'm sure others will pipe up with more knowledge than me. There's guys here that can start your truck from a thousand miles away.

Trust a dealer?? Would you be interested in buying a Rolex while your at it? It's a $10,000 watch but I'll let you have it for $30.
 
6.5TD Burb99 said:
Symptoms:
When you try and start the burb it struggles a lot. Does not want to start at all. However, after several tries it eventually starts and will continue to run if the gas peddle is pushed down even just a little. Once you let off the peddle it struggles and then stalls.

Thanks is advance.
Click to expand...

Does it have to crank a lot before it tries to fire, then sputter, then crank more, sputter, crank a little less before sputter, fires, dies, crank a bit more, sputter, fires runs rough, maybe dies again and have to do another crank/sputter/run rough cycle before it will stay running though maybe rough for a couple minutes before it finally starts to smoothout and stay running? If so, suspect air somehow getting into the fuel system. Once I got my old 83 6.2 Chev running it would run good until I let it set for a couple hours or more. Unlike a gasser, air in a diesel fuel system will cause headaches trying to get them started and running.

To check for air replace the fuel return line coming out of the IP with a clear line. You'll find this line by looking between the thermostat housing and the upper intake manifold. My 6.5 is a 94 so it may not be exactly the same as yours, but it will be close. There will be two black fuel lines almost side by side in an upside down "U" shape. Both will be attached on the front side (closest to the radiator) to a 1/4" steel fuel line going across the front of the motor. The one closer to the driver side of the motor will be attached to the IP on the rearmost end of the line. The other will be attached to a steel line going back in under the intake manifold (return to the fuel tank). Get some 1/4" clear plastic tubing about 6" long and put in place of the IP line. The pressure is very low on this line so almost any clear tube will work.

Now, next time you try to start your Burb have somebody watch the clear line. If you have air in the fuel line problems the clear line will look like the water above a scuba diver, air bubbles like crazy. If this is the case, finding the source of the air leak can take a lot of time and trial and error work. Others better than me may be able to do a better job of guideing you through the process. But, check ALL of your hard and soft fuel lines for any kind of damage, cuts/splits/cracks, loose fittings etc all the way back to the fuel tank. Sometimes all you'll find will be some wetness on the outside of the fuel line. Sometimes there will be no visible leaks. What may then be happening is that the air will be sucked in after the motor is shut down and the fuel is cooling and contracting and creating a vacuum in the line.

Let me know what you find out.
Don

ps---be cautious about doing a lot of cranking on the starter without cool down time. 6.2/6.5 starters are expensive and will burn out with repeated overheating from extended cranking.
 
Last edited:
:welcome5::welcome5:

It will normally be a simple problem, usually one of three things Fuel delivery, electrical or GPs. Keep posting what you are doing and you will be running great in no time. Follow the advise of the posts above.
 
This is what I know so far. More to come.

Problem: Explain your problem in concise language (ie: Cranks but won’t fire). _cranks, wont start if does start does not stay started, if running it stalls while driving ___________________________

Demographics: tell us about your truck and your ambient conditions:

- Year: _1999_____
- Truck model and class (ie: c2500) ____Suburban__2500___
- Automatic or Standard ____automatic______
- Mileage: (indicate miles or km) _162000________
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) ______What I know about: Fuel Filter,D-Tech PMD and moved(in 2008), glow plugs, boost control solenoid, _____
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? ____turbo__________
- Ambient outside temp: (indicate *C or *F) ____80's______
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) ________diesel_
- What fuel additives are you using? __na_________
- Where are you located? _________SE TN____

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter ______lifetime filter but don't know when replaced___
- Fuel filter _____last week____
- CDR Valve? _________
- Coolant – last flushed/replaced at _____________
- Oil – synthetic/regular, changed at ___________
- Batteries – state of charge, (matched set) replaced at _____________
- Battery cables and grounds (removed, cleaned and tightened): _______last week_______
- Glow Plugs - how many miles on them? purchased 12-1-08, dont know milage What type? ______receipt states : 6.5 GMC 94-00_______
- Injectors - last changed at ______dont know_________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? ___trying to start___________
- How was the truck running fine before this problem appeared? ________yes_____
- Has this problem ever happened before? ______no_________________
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) ___N_ And? ________


Diagnostics:

1] Starting:
1a] Does the engine start? _________
1b] Does the engine crank over? ________
1c] Are your batteries fully charged? ___pretty sure______
1d] Have you removed, cleaned, and tightened all battery connections? _______Yes_
1e] Does your Wait to Start light come on for a time? How long? _________
1f] Does your glow plug light come on? _________ For how long? _________
1g] Do you see smoke from the exhaust while cranking? What color? ___not while cranking_____
1h] Does the Service Engine Light Glow during Start/bulb check? _____yes___

2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____________
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? _________
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? ___________
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ___________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) _remote mounted__________
3b] Condition of Extension harness (if used) Vendor or Homemade? __vendor_______
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _________
3d] PMD Make: _D-Tech__________
3e] PMD Age: ______about 2 years_______

4] Stalling Issues
4a] Do you experience stalling only when hot? _______dont know_____
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ___lack of accelertion ___
4c] Does pouring cool water over the IP seem to help with restarting? _________
4d] Is stalling momentary (engine recovers)? _________
4e] Does SES light come on when engine hiccups? _________
4f] Does cruise control quit working when engine hiccups? ___________
4g] Does re-starting seem to reset engine, restoring cruise and power? _________
4h] Changes to dash lights or instruments during stalling events? ___________

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _______
5b] Any bubbles or oil film in coolant overflow tank? _______
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? __________
5d] Excessive white smoke from exhaust on cold start? _________
5e] Excessive black smoke from exhaust under hard acceleration? __________

6] Performance Issues
6a] Do you have gauges (boost, EGT) ? __dont know_________
6b] Maximum boost under load? __dont know __________
6c] Have you added a performance PCM (reflash) or Chip? ________dont know______
6d] Have you changed exhaust / downpipe / crossover? ___no_____________
6e] Wastegate – mechanical or vacuum (OEM)? _____dont know_________

7] Temperature-related Issues:
7a] Single or dual thermostats? ____dont know________
7b] Have you replaced them lately? Manufacturer of replacements? _________
7c] Have you pulled and cleaned Radiator and coolers lately? _____no_______
7d] Have you replaced the fan clutch? Manufacturer of replacement? ______no__
7e] (winter) Have you tested your antifreeze? Good to what temp? _____no_____
7f] (winter) Are you using a winter grille cover? ___________

List and describe any other factors which are not addressed in this checklist. We can’t see, hear, smell, or touch your truck, so the more descriptive information you can give, the more likely it is that somebody can assist you.

_________________________________
 
Welcome!! Another thing to checkis the fuel cap.Many times they are replaced with the wrong cap. It MUST say diesel fuel only on it. If it is a diesel cap ,the vent in the cap could be plugged causing a vacume in the tank. Try running with the cap slightly loose. Doing the checklist will familiarize you with the truck and engine. If there is parts of the checklist you don't understand be shure to ask for explanations. We love sucess stories.
Do not under any circumstances trust a dealer to do ANY work on a 6.5.
 
AK I was just typing the same thing then had to reboot my modem, POS!!

Sounds like its not getting fuel, Blow out the lines, If your not sure how just ask. Change filter. You might even check fuel pressure before doing anything.
What brand/color PMD?
All black wires in the Ext harness is not a good sign.
 
Do test #2, the Lift Pump. If LP is bad, then it has the same symptoms like PMD.

Of course, PMD can be bad also. Is the PMD on a heatsink in the front?

Have you checked to see if you have any SES?
 
Waiting to get vehicle back from dealer. Will work on it today with help from my brother. Will give progress. Thanks again.
 
Well this is the brother of 6.5TD Burb99 chiming in here. I was reading over all of the thread here and just wanted to add a small bit to the symptom list before we get the vehicle back here from the dealer.

The vehicle struggles mightily to start, though it eventually does. Then the idle is rough for a while eventually becoming normal (to my ears). If you are brave enough to take it for a test drive at that point it likes to stall right in the middle of normal operation. It just dies while you are going down the road at 35 mph.

I don't know if that changes any of the suggestions above but just though I might clarify.

Great forum by the way. We here in TN appreciate all of the help.
 
Still sounds like same problem. Check fuel system/pressure first as it is cheaper. If thats all good it could also be PMD/cable problem. Check the grounds at rear pass side intake.
 
Need to get that back from the STEALER ASAP!! Especially if they are charging diagnostics, because they dont know how to diagnose these, dont trust them they just go by the manual and thats not diagnostics, just part swapping. They have nothing to diagnose air in the fuel, bad PMDs, or bad fuel pressure. Which are the main causes of problems.

Its always good to be able to read the DTC from the computer.

The list doesnt have the bulb check, but do you always get the SES light while ignition is ON? You should, as well as the GP/WTS light for a little while and some other bulb tests the truck does. If SES light doesnt always come on then you have an ignition to PCM power problem. IGN also sends power to the PMD and IP fuel shutoff solenoid.

Check the fuel pressure at the drain T-valve on the T-stat crossover. That goes to a pre-filter output on the fuel filter manager (FFM). And when you turn the key in an OBDII truck it should run the lift pump (LP) for about 20 seconds or so. Then go off until you crank. You need to have at least 5psi there, if you have none you found your problem. Air can enter anywhere if that LP is not working, and it will still easily enter anywhere between the fuel tank and LP where steel fuel lines have rusted. Check out the lines on top of the fuel tank if you can.

PMD/FSD also causes these exact symptoms, as it provides the signal/power to the Injection Pump (IP) Fuel Solenoid. No smoke while cranking means no fuel. If PMD isnt sending signal wont start. There is a way to see if it is sending the signal/power while cranking. The line that goes to pin B of the PMD should be ouputting 1.2VAC while cranking (has to be all plugged in to test). Easier just to swap with another one to test, and eliminate the extension as a possible problem.

Make sure there is still a black wire grounded to the top of the IP that comes out of the same wire loom that the PMD wires do. Then check the grounds on the passenger side, back of engine/head.

The IP's fuel shutoff solenoind is the cylinder on top of the IP. With the IGN ON it should have 12V to it and you would hear and feel it click as it pulls the plunger up to allow fuel flow. This is a redundant function and if you suspect a problem pull it off apply 12V to see if plunger retracts or just pull the plunger out with a snap ring pliers and reinstall it.
 
Last edited:
buddy said:
Need to get that back from the STEALER ASAP!! Especially if they are charging diagnostics, because they dont know how to diagnose these, dont trust them they just go by the manual and thats not diagnostics, just part swapping. They have nothing to diagnose air in the fuel, bad PMDs, or bad fuel pressure. Which are the main causes of problems.

Its always good to be able to read the DTC from the computer.

The list doesnt have the bulb check, but do you always get the SES light while ignition is ON? You should, as well as the GP/WTS light for a little while and some other bulb tests the truck does. If SES light doesnt always come on then you have an ignition to PCM power problem. IGN also sends power to the PMD and IP fuel shutoff solenoid.

Check the fuel pressure at the drain T-valve on the T-stat crossover. That goes to a pre-filter output on the fuel filter manager (FFM). And when you turn the key it should run the lift pump (LP) for about 20 seconds or so. Then go off until you crank. You need to have at least 5psi there, if you have none you found your problem. Air can enter anywhere if that LP is not working, and it will still easily enter anywhere between the fuel tank and LP where steel fuel lines have rusted. Check out the lines on top of the fuel tank if you can.

PMD/FSD also causes these exact symptoms, as it provides the signal/power to the Injection Pump (IP) Fuel Solenoid. No smoke while cranking means no fuel. If PMD isnt sending signal wont start. There is a way to see if it is sending the signal/power while cranking. The line that goes to pin B of the PMD should be ouputting 1.2VAC while cranking (has to be all plugged in to test). Easier just to swap with another one to test, and eliminate the extension as a possible problem.

Make sure there is still a black wire grounded to the top of the IP that comes out of the same wire loom that the PMD wires do. Then check the grounds on the passenger side, back of engine/head.

The IP's fuel shutoff solenoind is the cylinder on top of the IP. With the IGN ON it should have 12V to it and you would hear and feel it click as it pulls the plunger up to allow fuel flow. This is a redundant function and if you suspect a problem pull it off apply 12V to see if plunger retracts or just pull the plunger out with a snap ring pliers and reinstall it.
Click to expand...

That sir, is an excellent post!

Great info.
 
You must log in or register to reply here.
Back
Top