Spartan Offroad
New Member
Hi I am new here but not new to 6.5's. I was recommended to come here from a member of another forum that I have been active on for a very long time. If anyone can help it would be greatly appreciated:
Problem: Explain your problem in concise language (ie: Cranks but won’t fire).
I have a 1995 GMC 6.5 turbo diesel. For the most part it has been running great up until recently. It has been my daily driver for the past two years. It has recently developed a PMD type issue.
The issues are: Loss of power, hard start, stalling but will restart, surging, and general rough running.
What happens is the truck runs great and then all of a sudden at some point it has PMD type issues. If I switch out the PMD for a known good unit the truck then runs great again until some point later in the day when the issues will come back but the issues are not always exactly the same. Again, if the PMD is switched out the issue is immediately resolved. I have been going back and fourth between 3 pmd's to keep the truck running. 2 of those PMD's I removed from other trucks and they were working fine, the third PMD is new.
Items that have been recently replaced include the wastegate solenoid, lift pump, oil pressure switch, glow plug controller, computer, pmd, and pmd cable, fuel filter. We also checked all the grounds we could find, pmd cable pins, battery terminals, ect. The pmd is remotely mounted and on a heat sink.
Demographics: tell us about your truck and your ambient conditions:
- Year: 1995
- Truck model and class (ie: c2500) c2500
- Automatic or Standard Auto
- Mileage: (indicate miles or km) 98,000
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc)
lift pump, oil pressure switch, glow plug controller, computer, wastegate solenoid pmd, and pmd cable, fuel filter
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? Turbo F-Vin
- Ambient outside temp: (indicate *C or *F) 95*F and very humid
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _________
- What fuel additives are you using? N/A
- Where are you located? Florida
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter in last year, about 6k miles ago
- Fuel filter - July 2016
- CDR Valve? not since I have owned it
- Coolant – last flushed/replaced at - July 2016
- Oil – synthetic/regular, changed at - Dino July 2016
- Batteries – state of charge, (matched set) replaced at - matched set Jan 2014
- Battery cables and grounds (removed, cleaned and tightened): all recently cleaned
- Glow Plugs - how many miles on them? - most likely original What type? _____________
- Injectors - last changed at - unknown
History: (Describe how the problem first appeared.)
- What were you doing when it happened? - varies under normal operation
- How was the truck running fine before this problem appeared? excellent
- Has this problem ever happened before? Yes
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) No
[FONT="]
[/FONT] Diagnostics:
1] Starting:
1a] Does the engine start? Always but sometimes needs to crank longer
1b] Does the engine crank over? - Yes
1c] Are your batteries fully charged? I believe so
1d] Have you removed, cleaned, and tightened all battery connections - yes recently
1e] Does your Wait to Start light come on for a time? How long? Bulb burt out long afo
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) ? _________
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? Yes
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? No
3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) remote on heat sink
3b] Condition of Extension harness (if used) Vendor or Homemade? just checked and replaced
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. good as far as I can tell
3d] PMD Make: Dorman
3e] PMD Age: New
4] Stalling Issues
4a] Do you experience stalling only when hot? Mostly hot or just after starting when cold
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) No
4c] Does pouring cool water over the IP seem to help with restarting? No
4d] Is stalling momentary (engine recovers)? Most of the time
4e] Does SES light come on when engine hiccups? Yes
4f] Does cruise control quit working when engine hiccups? _YES
4g] Does re-starting seem to reset engine, restoring cruise and power? sometimes
4h] Changes to dash lights or instruments during stalling events? _No
5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _No
5b] Any bubbles or oil film in coolant overflow tank? _No
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? _No
5d] Excessive white smoke from exhaust on cold start? _No
5e] Excessive black smoke from exhaust under hard acceleration? _Some black smoke under acceleration but only if I really get on it
6] Performance Issues
6a] Do you have gauges (boost, EGT) ? NO
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 (OEM)? OEM
7] Temperature-related Issues:
No cooling issues, temp typically runs under 180*
Thank you for your time, any help is appreciated.
George
Problem: Explain your problem in concise language (ie: Cranks but won’t fire).
I have a 1995 GMC 6.5 turbo diesel. For the most part it has been running great up until recently. It has been my daily driver for the past two years. It has recently developed a PMD type issue.
The issues are: Loss of power, hard start, stalling but will restart, surging, and general rough running.
What happens is the truck runs great and then all of a sudden at some point it has PMD type issues. If I switch out the PMD for a known good unit the truck then runs great again until some point later in the day when the issues will come back but the issues are not always exactly the same. Again, if the PMD is switched out the issue is immediately resolved. I have been going back and fourth between 3 pmd's to keep the truck running. 2 of those PMD's I removed from other trucks and they were working fine, the third PMD is new.
Items that have been recently replaced include the wastegate solenoid, lift pump, oil pressure switch, glow plug controller, computer, pmd, and pmd cable, fuel filter. We also checked all the grounds we could find, pmd cable pins, battery terminals, ect. The pmd is remotely mounted and on a heat sink.
Demographics: tell us about your truck and your ambient conditions:
- Year: 1995
- Truck model and class (ie: c2500) c2500
- Automatic or Standard Auto
- Mileage: (indicate miles or km) 98,000
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc)
lift pump, oil pressure switch, glow plug controller, computer, wastegate solenoid pmd, and pmd cable, fuel filter
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? Turbo F-Vin
- Ambient outside temp: (indicate *C or *F) 95*F and very humid
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _________
- What fuel additives are you using? N/A
- Where are you located? Florida
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter in last year, about 6k miles ago
- Fuel filter - July 2016
- CDR Valve? not since I have owned it
- Coolant – last flushed/replaced at - July 2016
- Oil – synthetic/regular, changed at - Dino July 2016
- Batteries – state of charge, (matched set) replaced at - matched set Jan 2014
- Battery cables and grounds (removed, cleaned and tightened): all recently cleaned
- Glow Plugs - how many miles on them? - most likely original What type? _____________
- Injectors - last changed at - unknown
History: (Describe how the problem first appeared.)
- What were you doing when it happened? - varies under normal operation
- How was the truck running fine before this problem appeared? excellent
- Has this problem ever happened before? Yes
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) No
[FONT="]
[/FONT] Diagnostics:
1] Starting:
1a] Does the engine start? Always but sometimes needs to crank longer
1b] Does the engine crank over? - Yes
1c] Are your batteries fully charged? I believe so
1d] Have you removed, cleaned, and tightened all battery connections - yes recently
1e] Does your Wait to Start light come on for a time? How long? Bulb burt out long afo
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) ? _________
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? Yes
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? No
3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) remote on heat sink
3b] Condition of Extension harness (if used) Vendor or Homemade? just checked and replaced
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. good as far as I can tell
3d] PMD Make: Dorman
3e] PMD Age: New
4] Stalling Issues
4a] Do you experience stalling only when hot? Mostly hot or just after starting when cold
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) No
4c] Does pouring cool water over the IP seem to help with restarting? No
4d] Is stalling momentary (engine recovers)? Most of the time
4e] Does SES light come on when engine hiccups? Yes
4f] Does cruise control quit working when engine hiccups? _YES
4g] Does re-starting seem to reset engine, restoring cruise and power? sometimes
4h] Changes to dash lights or instruments during stalling events? _No
5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _No
5b] Any bubbles or oil film in coolant overflow tank? _No
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? _No
5d] Excessive white smoke from exhaust on cold start? _No
5e] Excessive black smoke from exhaust under hard acceleration? _Some black smoke under acceleration but only if I really get on it
6] Performance Issues
6a] Do you have gauges (boost, EGT) ? NO
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 (OEM)? OEM
7] Temperature-related Issues:
No cooling issues, temp typically runs under 180*
Thank you for your time, any help is appreciated.
George
