optical sensor is serviceable. I've never messed with it but many have for a little more fuel.
Was your old PMD bad? You could put the old one on the extension harness and then try without the extension. Just a thought since your running out of options.

 

The optical sensor is serviceable by a pump shop only. It will change the whole calibration. Can you find out exactly what the codes were? From the sounds of it you need a new injection pump. I wouldnt know what to say as to whether $1500 is good for your truck. I havent seen it either.

 

Whoa ya'll jumping to IP swap already, a bit premature. lots of other stuff to do, you said swapped PMD, with new or new used, what remote locator kit did you use?

bad OPS will not prevent a start unless you have air in the system and the IP can't pull it's own fuel.

These are fly by wire controlled truck, which means it needs "clean-tron flow paths" to get proper voltages to PCM ands devices that talk to the PCM.

Have you checked that fuel shutdown solenoid on top of IP is opening, are ALL ground connections clean and tight, not just the ones going to the battery, Optic sensor is a field replaceable unit.

have you checked for positive lift pump output, at diagnostic connector pin G, apply +12v to that pin and lift if healthy will run, you also need to put a test vac/press gage on the drain outlet tee of filter manager to see how much lift you are seeing.

Rarely if ever does a IP just quit, when they go bad they have driveability issues, straight up no starts are 99.9% of time not caused by the IP itself.

 

Thanks for all the info guys . To answer some questions , it was a used pmd and im not sure what kind of remote kit . Im sort of broke so i bought them off of e-bay . But im sure their not the problem because the truck had drivability issues even though I replaced these parts , nothing changed . But after i replaced the lift pump and ops I noticed a tremendous difference it ran like crap at first but that was do to air in the lines because i forgot to purge the air . After the air was purged it ran like a new truck . It sat overnight and still will not start . I think that i might have to break down and take it to a shop because I have tested everything that you all have told me but I dont know how to check the electronic stuff . I need to get my hands on a real mechanics manual for this truck because chiltons aint cuttin it no more . Thank everyone for all your help and if ther is any more info im willin to try . By the way how much should it cost for a pump re-build .

 

Ops? You replaced the encoder(optical sensor)? The pump needs calibration after that is done. I know the broke feeling believe me. Hopefully you get her up and running soon

 

No. Apparently I mispoke . I replaced the oil pressure switch , I dont know where the optical sensor is . I think we are going to start tearing some stuff apart soon because I got some people that have a little more knowledge then me willing to help . Unfortunately there are no pump shops around so I guess I might have to replace mine . Any suggestions?

 

my uncle has the exact same problem with his 95 yukon, shut it down one night and the next morning it ran for 4 second or so and hasnt started since.

He had the codes read and he got some cam sensor error or something (probably this optical sensor you speak of), his truck is in the shop now i'll post up what was wrong as soon as i get the specs on it.

 

did you fiddle with your PMD some more and try the old one? Worth a shot before you tear it apart.

 

Used PMD is just that "used", once subjected to heat they are suspect, and on the IP they are subjected to heat. And #1 headache with the 6.5 until you relocate with Heath remote driver. OPS will not prevent a engine start, unless your tank sock is plugged, or filter manager or system is airbound, IP can suck it's own fule

This is something we use at my regular hangout:

Copy/paste into a thread with answer and we'll be better able to assist you in troubleshooting.

6.5 Engine Diagnostic Troubleshooting Checklist


Copy and paste this checklist into a new post, then answer all the questions by typing in your data into the blanks as indicated - click in the middle of the blank, start typing.


Problem: Explain your problem in concise language (ie: Cranks but won’t fire). ____________________________

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

- Year: ______
- Truck model and class (ie: c2500) _________
- Automatic or Standard __________
- Mileage: (indicate miles or km) _________
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) ___________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? ______________
- Ambient outside temp: (indicate *C or *F) __________
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _________
- What fuel additives are you using? ___________
- Where are you located? _____________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _________
- Fuel filter _________
- 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): ______________
- Glow Plugs - how many miles on them? _________ What type? _____________
- Injectors - last changed at _______________


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


Diagnostics:

1] Starting:
1a] Does the engine start? _________
1b] Does the engine crank over? ________
1c] Are your batteries fully charged? _________
1d] Have you removed, cleaned, and tightened all battery connections? ________
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? ________

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) ___________
3b] Condition of Extension harness (if used) Vendor or Homemade? _________
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _________
3d] PMD Make: ___________
3e] PMD Age: _____________

4] Stalling Issues
4a] Do you experience stalling only when hot? ____________
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ______
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? ___________
6b] Maximum boost under load? ____________
6c] Have you added a performance PCM (reflash) or Chip? ______________
6d] Have you changed exhaust / downpipe / crossover? ________________
6e] Wastegate – mechanical or vacuum? ______________

7] Temperature-related Issues:
7a] Single or dual thermostats? ____________
7b] Have you replaced them lately? Manufacturer of replacements? _________
7c] Have you pulled and cleaned Radiator and coolers lately? ____________
7d] Have you replaced the fan clutch? Manufacturer of replacement? ________
7e] (winter) Have you tested your antifreeze? Good to what temp? __________
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.

 

i am having this same problem except my IP is brand new? put it in and it wont fire fuel is getting to the pump but not past that? suggestions?