Injection Pump troubleshooting

[GTOJohn]

I am very new to diesel engines and just recently picked up a non-running '95 K2500 6.5 Turbo Diesel 4x4 extended cab that I would like to use for towing. The body has 333K miles on it and supposedly the engine has 70K miles. The diagnosis from the seller was that the "fuel pump" wasn't working and there was voltage at the pump, but no pressure at the fuel manager. So I replaced the lift pump and found no fuel at the fuel injectors.

My buddy told me that it is time to replace the injection pump, but I would like to troubleshoot this further. I read a lot here tonight and learned a lot. It is a fantastic forum and you guys obviously know a lot about these engines. Will you please tell me what I need to do to make sure that I don't have a PMD problem, fuse, wire, pump, etc?

Problem: Explain your problem in concise language (ie: Cranks but won’t fire). ___Cranks but won’t fire. New Lift Pump, fuel present at fuel manager, but not at injector._________________________

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

- Year: __1995____
- Truck model and class (ie: c2500) _K2500________
- Automatic or Standard ___Standard_______
- Mileage: (indicate miles or km) __333K_______
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) _____?______
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? ___Turbo___________
- Ambient outside temp: (indicate *C or *F) ____80*F______
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) ____?_____
- What fuel additives are you using? _____None______
- Where are you located? ____Lebanon, OH_________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter ____?_____
- Fuel filter ___0 miles ago______
- CDR Valve? ____?_____
- Coolant – last flushed/replaced at _____?________
- Oil – synthetic/regular, changed at _____?______
- Batteries – state of charge, (matched set) replaced at ___New__________
- Battery cables and grounds (removed, cleaned and tightened): _____Ok_________
- Glow Plugs - how many miles on them? ____?_____ What type? _____?________
- Injectors - last changed at _____?__________


History: (Describe how the problem first appeared.)
- Describe any related factors that might be part of the problem. _____Lift Pump just replcaed_________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) __Y__ And? __None stored______


Diagnostics:

1] Starting:
1a] Does the engine start? ___No______
1b] Does the engine crank over? __Yes______
1c] Are your batteries fully charged? ___Yes______
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? __Yes, about 10 seconds or less_______
1f] Does your glow plug light come on? ____?_____ For how long? ____?_____
1g] Do you see smoke from the exhaust while cranking? What color? __No______
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? _____Yes_______
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? ___Yes______
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? ____No_____
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ____Yes_______

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) __on pump_________
3b] Condition of Extension harness (if used) Vendor or Homemade? __looks stock_______
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. ____?_____
3d] PMD Make: _____?______
3e] PMD Age: _____?________


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.

(Nothing that I can think of)

Thanks,
John

 

[WarWagon]

Voltage does not mean amperage. The Oil Pressure Switch can burn and pass 7 volts to the fuel pump and no amps - Lift Pump will not work. The pumps can also rattle away with a stuck valve and pump no fuel.

Unless you have pressure at the fuel filter water drain your Lift Pump troubleshooting is not done. Troubleshoot the IP after you have fuel to it...

Your next project before towing needs to be the cooling system upgrade and radiator/condenser/oil cooler cleaning by pulling the radiator out and the oil cooler away from the condenser.

 

[GTOJohn]

Sorry that I forgot to mention. I do have plenty of fuel at the fuel filter drain now that I have replaced the lift pump. I have also replaced the filter and have bled air from the drain.

Thanks,
John

 

[Rodd]

Now that you have replaced the LP you need to open the t-valve and see if you have fuel coming out with the key in the on position. Note if the stream is a solid good stream or does it trickle out. When replacing the fuel filter the fuel needs to work its way back up to the fuel filter manager before it can go out to the IP. What I like to do when I replace the fuel filter is fill the filter manager up 1/2 way with diesel klean or some other type of injector cleaner. Then put the filter in and close it tight. It should only take a few cycles starting the truck before it turns over. That is if the IP and PMD are good.

If that doesn't work the next step is to get a known good PMD and plug it in to see if it starts. If it does then that is your problem if it doesn't then it looks like your IP. Unplug the optical sensor on the IP and try to start. If the Opt sensor is bad it might start up. If not you are looking at most likely the IP.

 

[ak diesel driver]

I vote for PMD

 

[GTOJohn]

Now that you have replaced the LP you need to open the t-valve and see if you have fuel coming out with the key in the on position. Note if the stream is a solid good stream or does it trickle out. When replacing the fuel filter the fuel needs to work its way back up to the fuel filter manager before it can go out to the IP. What I like to do when I replace the fuel filter is fill the filter manager up 1/2 way with diesel klean or some other type of injector cleaner. Then put the filter in and close it tight. It should only take a few cycles starting the truck before it turns over. That is if the IP and PMD are good.

If that doesn't work the next step is to get a known good PMD and plug it in to see if it starts. If it does then that is your problem if it doesn't then it looks like your IP. Unplug the optical sensor on the IP and try to start. If the Opt sensor is bad it might start up. If not you are looking at most likely the IP.

Excellent info, Rodd. What is the t-valve?

I vote for PMD

I hope that it is the problem instead of the IP, ak... $$$$

Thanks,
John

 

[Pruittx2]

T valve is a little brass vale located on the thermostat housing,, open it and fuel will drain out the bottom hose on that valve. good stream = steady flow to the ip.

 

[GTOJohn]

T valve is a little brass vale located on the thermostat housing,, open it and fuel will drain out the bottom hose on that valve. good stream = steady flow to the ip.

Thanks Pruitt... I saw that valve and I and wondered what it was. I'll give it a shot.

Thanks for everyone's help.
John

 

[ak diesel driver]

you need to read the lift pump/OPS sticky also. 94-95 are diff than the newer ones

 

[NVW]

I also vote for a pmd but would also check the ecm fuse in the under hood fuse box. clean the fuse spades up with emery cloth to rule that out.

 

[WarWagon]

You got fuel. Now troubleshoot the electronics.

Key on bulb check.... Do you have a Service Engine Soon light?
I would check (disassemble and clean) the grounds anyway.

No? Gauge fuse, ECM fusible link broken at firewall passenger side main bus junction, bad grounds esp the one under the trans dipstick on the engine.

Yes? Then paper clip the ALDL connector and read the codes if any. Here is how jump A to B, yes look closely and the ALDL connector has the letters on it:
http://www.thetruckstop.us/forum/showthread.php?t=497

 

[GTOJohn]

Just to follow-up on the items that I did today:

1. Cleaned any grounds that I could find.
2. Checked all fuses. (All ok)
3. Opened the T-valve and turned on the ignition and cranked (No fuel stream, just some dampness)
4. SES Light comes on, jumpered the ALDL and no codes were stored.
5. Unplugged the Optical sensor. (No difference)

Testing in every case was to check the outlet of the T-valve (hose removed) and check the open fuel injector port. No fuel stream was found. I guess the next step is to swap out a PMD? None are available locally at the parts store, but they do carry the injection pump a$$embly. I am considering buying a used guaranteed unit for testing from ebay. If that works, I will buy a new unit and the relocation kit. Is the ebay kit the best one or are there others?

Thanks,
John

 

[ak diesel driver]

hold your horses!!! if no fuel out the water drain we need to verify problem. You said you were getting fuel earlier. I assume from the bleeder screw on top of the filter? Check and make sure the tube going to the water drain is not plugged. If it's not plugged then you probably found your problem which would be a lift pump/ OPS problem. Get that fixed first before anything else. No fuel=no run

 

[GTOJohn]

Sorry for the confusion. I removed the drain hose downstream of the T-valve and looked for fuel coming directly out of the valve and found nothing. There is plenty of fuel and pressure available at the bleeder screw at the top of the filter. Does this mean that the lift pump is working? I also checked the gas cap today and no whoosh when loosening it.

What should I check next?

Thanks,
John

 

[Rodd]

Sorry for the confusion. I removed the drain hose downstream of the T-valve and looked for fuel coming directly out of the valve and found nothing. There is plenty of fuel and pressure available at the bleeder screw at the top of the filter. Does this mean that the lift pump is working? I also checked the gas cap today and no whoosh when loosening it.

What should I check next?

Thanks,
John

Just to clarify, where did you disconnect the hose to the t valve? There is a hose coming out of the bottom of the FFM going to the T valve and then another hose from the T valve that is open, usually a foot long or so. I find the best way to check the flow through the t valve is to take an old clear water bottle and put the open end of the hose in it. Then open the T valve. Next go turn the key to the on position. Don't crank!!!! You should see fuel streaming out. Even though the bleeder valve on top of the filter passes fuel you still want to make sure you have fuel through the T valve. If and when you get a water in fuel light you will need to drain it from there. If you have fuel at both the bleeder valve and the t valve your next step would be the Ops (oil pressure switch). It is a Pita to change but it's easy. You might want to buy a OPS relocation kit from one of our vendors but you don't need to. You have to take off the upper and lower intake in the center of the top of the engine to get at it. The ops is only about $25-$30 at autozone. That would be my next step since it is cheap and you will probably want to do it any way.

 

[GTOJohn]

I disconnected the footlong hose from the t-valve that is open on the end, thinking that it may be plugged. I turned on the key and there is no fuel there. What does that mean?

Thanks,
John

 

[NVW]

On the 95 to run the LP put the gear shift in drive and turn ign. to start. As others said pull the hose up and place in a bottle and open the T valve.

 

[Rodd]

I disconnected the footlong hose from the t-valve that is open on the end, thinking that it may be plugged. I turned on the key and there is no fuel there. What does that mean?

Thanks,
John

Did you try and blow threw it to make sure it is or isn't plugged?

 

[racer55]

if when the drain hose at the t-valve is removed and the t-valve is opened you do not have any fuel flowing it means there is probably a restriction in the line from the filter housing to the t valve,or you still have lift pump,lift pump relay/ecm( depends on year of vehicle for relay or ecm operation at key on only and I forget the year they switched systems) or oil pressure switch problem.

you need to determine where the cause of no fuel is before condemning any other parts.
there is a small screen under the fuel filter that can become clogged as well as a sock/strainer in the fuel tank on the sending unit that can also become clogged.

since you have fuel at the filter bleed tap it would seem the lift pump is working but it may not be working well enough or there are blockages between the filter manager housing and the t-valve or the filter manager housing and the injection pump.

also it is highly reccommended to use only an oil pressure switch from the dealer for best results,a good preventative maintenace item is to add a relay to the lift pump/oil pressure switch circuit so do a search for that modification here as well.

 

[GTOJohn]

This project fell off the priority list, but I have made some recent progress. I pulled the filter housing and blew out the hoses to make sure that there wasn't a restriction and then reassembled everything and primed the filter housing. I also installed a new PMD module and relocation kit (not mounted, just hooked up). So in summary, here is what I have replaced so far:

Lift Pump
Fuel Filter
PMD Module

I have plenty of fuel pressure at the bleed port on the filter housing, but none at the injector, with the line removed. A question about the OPS... If it is bad, does it disable the lift pump or the injection pump? Is there an easy way to jump it out to test whether or not it is working properly? I am not completely sure I know where it is on the engine.

I appreciate any further suggestions, but I am guessing that I need a new injection pump. I don't want to throw money at the truck, so would like to further troubleshoot the system.

Thanks,
John