reddtekk
Noob, but quickly learning!
Greetings folks...
I've explored around a while but now I think it's time for me to start a fresh thread since I haven't found anything that I think is directly related to my issue.
Problem: Explain your problem in concise language (ie: Cranks but won’t fire). __Starts and runs. Throttle response sluggish in neutral or park. NO throttle response in drive or reverse.__
Demographics: tell us about your truck and your ambient conditions:
- Year: ___1994___
- Truck model and class (ie: c2500) ___K3500 DRW______
- Automatic or Standard ____Automatic______
- Mileage: (indicate miles or km) ____156000_____
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) _New GM PMD, have spare ECU w/Manual trans PROM (more details below)_
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? _F Turbo, non-EGR_
- Ambient outside temp: (indicate *C or *F) _65*F_
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _Pump(#2?) Diesel_
- What fuel additives are you using? _2oz/5gal. PowerService DieselKleen +Cetane Boost_
- Where are you located? __Waterbury, CT, USA__
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _OK__
- Fuel filter __OK__
- CDR Valve? __Unknown__
- Coolant – last flushed/replaced at __Unknown (still green...)__
- Oil – synthetic/regular, changed at _Unknown...not too thick but lots of soot_
- Batteries – state of charge, (matched set) replaced at _unmatched, hold good charge, maintained using trickle charger_
- Battery cables and grounds (removed, cleaned and tightened): _All OK_
- Glow Plugs - how many miles on them? _Unknown_ What type? _Unknown - may be original
_
- Injectors - last changed at _Unknown - may be original_
History: (Describe how the problem first appeared.)
- What were you doing when it happened? _Purchased truck in (worse than) current condition_
- How was the truck running fine before this problem appeared? _Judging from accident damage...likely_
- Has this problem ever happened before? _Unknown_
- Describe any related factors that might be part of the problem. _Weak cylinder. Cyl. 4 measures cooler than the rest using IR gun. DTC for cylinder imbalance on #4 and occasionally on #5._
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) _Y_ And? _Originally DTCs 34, 36, 94 and 95. Timing sounded very advanced. Cleared codes and lined IP up to timing marks. IP WAS positioned fully advanced (to end of slots):WTF::yikes::dr:. After lining up the injection pump mark with the timing cover mark the engine sounded much better and codes 34 and 36 haven't been back. Always pulls code 95 and sometimes also 94._
Diagnostics:
1] Starting:
1a] Does the engine start? _Yes, easiest when assisted with a little throttle (20% maybe, hold at 1500 rpm for about 20 seconds then let off and it idles without stalling. Otherwise will stumble but not quite keep running._
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, around 20-30 seconds when cold._
1f] Does your glow plug light come on? _Yes_ For how long? _about 30-40 sec. when cold_
1g] Do you see smoke from the exhaust while cranking? What color? _Yes, white_
1h] Does the Service Engine Light Glow during Start/bulb check? _Yes_
2] Fuel Issues (if not running):N/A
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)? __YES__
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? __N/A (USING RUBBER LINES IN PORTABLE CONTAINER - FUEL LINES RUSTED OUT AND HAVEN'T BEEN REPLACED YET.) TEMPORARY FUEL SYSTEM IS AIRTIGHT AND FUEL CONTAINER ADEQUATELY VENTED.__
3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) _Currently not mounted, attached to sizeable heat sink. Temp about 120*F after running over half an hour._
3b] Condition of Extension harness (if used) Vendor or Homemade? _Vendor, mediocre quality. Repaired accident damage where wires were cut and insulation compromised. Soldered together and insulated with heat shrink tubing. Questionable pins - very flimsy - but tests OK._
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _Factory harness grounded to factory position on IP. PMD heat sink not grounded._
3d] PMD Make: _GM_
3e] PMD Age: _New (less than 2 yrs old, used only to burn about 4 gal. fuel by idling in place to heat cycle in successful attempt to free stuck rings_
4] Stalling Issues N/A
4a] Do you experience stalling only when hot? _NO_
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? _NOT ATTEMPTED. HOT STARTS VERY EASY_
4d] Is stalling momentary (engine recovers)? _N/A_
4e] Does SES light come on when engine hiccups? _N/A_
4f] Does cruise control quit working when engine hiccups? _N/A_
4g] Does re-starting seem to reset engine, restoring cruise and power? __NO__
4h] Changes to dash lights or instruments during stalling events? __N/A__
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? _Unknown_
6] Performance Issues
6a] Do you have gauges (boost, EGT) ? __No__
6b] Maximum boost under load? _Unknown_
6c] Have you added a performance PCM (reflash) or Chip? __No__
6d] Have you changed exhaust / downpipe / crossover? _No_
6e] Wastegate – mechanical or vacuum (OEM)? __OEM__
7] Temperature-related Issues:N/A
7a] Single or dual thermostats? _SINGLE_
7b] Have you replaced them lately? Manufacturer of replacements? _NO_
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 BUT NOTHING SPLIT AND WE HAD A VERY COLD WINTER THIS YEAR_
7f] (winter) Are you using a winter grille cover? _NO_
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.
OK now that I'm done with the formalities:
The truck was not running when I got it. The wires for the PMD remote harness were severed in a small accident and the PMD was flattened. The previous owner bought a brand new GM PMD and did a poor job of botching the wires back together. I disassembled the harness and properly connected the wires by soldering and insulating with heat shrink tubing. Since I didn't have a PMD resistor, I soldered in a resistor of the appropriate value for a #5 resistor directly in the wiring harness.
The truck starts and runs. It warms up correctly and stays at about 195*f according to GMTDScan Basic. Runs with a weak cylinder - slight shudder. I suspect #4 injector because the cylinder is producing less heat than the rest (analyzed using IR gun) and the computer produces DTC 95 (cyl. 4 imbalance), sometimes also DTC 94(cyl. 5 imbalance). Mechanically the engine sounds sound with no audible rod, piston or valve noise to speak of - only the slight detonation clack consistent with a possible leaking injector.
Using the original ECM or the spare with the original EPROM swapped into it:
* Idles fine.
* No CEL
* Intermittent code 94 and 95
* RPM increases gradually when accelerator is depressed with transmission in park or neutral.
* RPM DOES NOT increase when the accelerator is depressed in either reverse or any forward gear. No audible change to idle when the accelerator is depressed. THIS IS THE ISSUE I'D LIKE HELP WITH.
For poops and giggles I tossed in the spare ECU using its original EPROM. I'm pretty sure it's off a manual transmission K truck with the 6.5TD. All was the same EXCEPT:
* I noted a VERY SLIGHT increase in RPM when the pedal was depressed.
On the original ECU with the original EPROM I get the following data shown in GMTDScan Basic:
ECT 195*f
RPM~650
TDCO -1.5*
Pump Timing~26*
Desired timing 4.5*
Actual timing 4.5*
injection pulse 2.15ms
All is the same on the spare ECU with the spare (wrong) EPROM except:
I didn't check Pump Timing.
TDCO -0.7*
Idle was slightly higher at ~680 RPM.
I verified function of all three APP sensors in GMTDScan Basic against values in the GM "1994 C/K, G and P3 TRUCK DRIVEABILITY AND EMISSIONS (DIESEL) SERVICE MANUAL SUPPLEMENT" manual, which contains the factory specs for the APP voltages.
The only thing I can see that is NOT in line is the injection pulse, which appears to be about 0.20ms greater than the value specified in the manual. Can that cause the issue I'm seeing? It looks like others are shooting for 8.5* desired timing. I wouldn't think that the desired timing would change if I moved the IP timing but I haven't tried it. Could it be the weak cylinder DTC? Has anyone else had (and hopefully solved) this sort of issue? I have NOT performed TDC Offset. I bought the cable needed for GMTDScanTech but will only buy the software license if the free version won't do what I need to make this beast run correctly.
Thanks in advance for any suggestions. I'll be glad to fill in any missing data as soon as I can.
_________________________________
I've explored around a while but now I think it's time for me to start a fresh thread since I haven't found anything that I think is directly related to my issue.
Problem: Explain your problem in concise language (ie: Cranks but won’t fire). __Starts and runs. Throttle response sluggish in neutral or park. NO throttle response in drive or reverse.__
Demographics: tell us about your truck and your ambient conditions:
- Year: ___1994___
- Truck model and class (ie: c2500) ___K3500 DRW______
- Automatic or Standard ____Automatic______
- Mileage: (indicate miles or km) ____156000_____
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) _New GM PMD, have spare ECU w/Manual trans PROM (more details below)_
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? _F Turbo, non-EGR_
- Ambient outside temp: (indicate *C or *F) _65*F_
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _Pump(#2?) Diesel_
- What fuel additives are you using? _2oz/5gal. PowerService DieselKleen +Cetane Boost_
- Where are you located? __Waterbury, CT, USA__
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _OK__
- Fuel filter __OK__
- CDR Valve? __Unknown__
- Coolant – last flushed/replaced at __Unknown (still green...)__
- Oil – synthetic/regular, changed at _Unknown...not too thick but lots of soot_
- Batteries – state of charge, (matched set) replaced at _unmatched, hold good charge, maintained using trickle charger_
- Battery cables and grounds (removed, cleaned and tightened): _All OK_
- Glow Plugs - how many miles on them? _Unknown_ What type? _Unknown - may be original
_- Injectors - last changed at _Unknown - may be original
_History: (Describe how the problem first appeared.)
- What were you doing when it happened? _Purchased truck in (worse than) current condition_
- How was the truck running fine before this problem appeared? _Judging from accident damage...likely_
- Has this problem ever happened before? _Unknown_
- Describe any related factors that might be part of the problem. _Weak cylinder. Cyl. 4 measures cooler than the rest using IR gun. DTC for cylinder imbalance on #4 and occasionally on #5._
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) _Y_ And? _Originally DTCs 34, 36, 94 and 95. Timing sounded very advanced. Cleared codes and lined IP up to timing marks. IP WAS positioned fully advanced (to end of slots)
:WTF::yikes::dr:. After lining up the injection pump mark with the timing cover mark the engine sounded much better and codes 34 and 36 haven't been back. Always pulls code 95 and sometimes also 94._Diagnostics:
1] Starting:
1a] Does the engine start? _Yes, easiest when assisted with a little throttle (20% maybe, hold at 1500 rpm for about 20 seconds then let off and it idles without stalling. Otherwise will stumble but not quite keep running._
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, around 20-30 seconds when cold._
1f] Does your glow plug light come on? _Yes_ For how long? _about 30-40 sec. when cold_
1g] Do you see smoke from the exhaust while cranking? What color? _Yes, white_
1h] Does the Service Engine Light Glow during Start/bulb check? _Yes_
2] Fuel Issues (if not running):N/A
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)? __YES__
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? __N/A (USING RUBBER LINES IN PORTABLE CONTAINER - FUEL LINES RUSTED OUT AND HAVEN'T BEEN REPLACED YET.) TEMPORARY FUEL SYSTEM IS AIRTIGHT AND FUEL CONTAINER ADEQUATELY VENTED.__
3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) _Currently not mounted, attached to sizeable heat sink. Temp about 120*F after running over half an hour._
3b] Condition of Extension harness (if used) Vendor or Homemade? _Vendor, mediocre quality. Repaired accident damage where wires were cut and insulation compromised. Soldered together and insulated with heat shrink tubing. Questionable pins - very flimsy - but tests OK._
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _Factory harness grounded to factory position on IP. PMD heat sink not grounded._
3d] PMD Make: _GM_
3e] PMD Age: _New (less than 2 yrs old, used only to burn about 4 gal. fuel by idling in place to heat cycle in successful attempt to free stuck rings_
4] Stalling Issues N/A
4a] Do you experience stalling only when hot? _NO_
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? _NOT ATTEMPTED. HOT STARTS VERY EASY_
4d] Is stalling momentary (engine recovers)? _N/A_
4e] Does SES light come on when engine hiccups? _N/A_
4f] Does cruise control quit working when engine hiccups? _N/A_
4g] Does re-starting seem to reset engine, restoring cruise and power? __NO__
4h] Changes to dash lights or instruments during stalling events? __N/A__
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? _Unknown_
6] Performance Issues
6a] Do you have gauges (boost, EGT) ? __No__
6b] Maximum boost under load? _Unknown_
6c] Have you added a performance PCM (reflash) or Chip? __No__
6d] Have you changed exhaust / downpipe / crossover? _No_
6e] Wastegate – mechanical or vacuum (OEM)? __OEM__
7] Temperature-related Issues:N/A
7a] Single or dual thermostats? _SINGLE_
7b] Have you replaced them lately? Manufacturer of replacements? _NO_
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 BUT NOTHING SPLIT AND WE HAD A VERY COLD WINTER THIS YEAR_
7f] (winter) Are you using a winter grille cover? _NO_
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.
OK now that I'm done with the formalities:
The truck was not running when I got it. The wires for the PMD remote harness were severed in a small accident and the PMD was flattened. The previous owner bought a brand new GM PMD and did a poor job of botching the wires back together. I disassembled the harness and properly connected the wires by soldering and insulating with heat shrink tubing. Since I didn't have a PMD resistor, I soldered in a resistor of the appropriate value for a #5 resistor directly in the wiring harness.
The truck starts and runs. It warms up correctly and stays at about 195*f according to GMTDScan Basic. Runs with a weak cylinder - slight shudder. I suspect #4 injector because the cylinder is producing less heat than the rest (analyzed using IR gun) and the computer produces DTC 95 (cyl. 4 imbalance), sometimes also DTC 94(cyl. 5 imbalance). Mechanically the engine sounds sound with no audible rod, piston or valve noise to speak of - only the slight detonation clack consistent with a possible leaking injector.
Using the original ECM or the spare with the original EPROM swapped into it:
* Idles fine.
* No CEL
* Intermittent code 94 and 95
* RPM increases gradually when accelerator is depressed with transmission in park or neutral.
* RPM DOES NOT increase when the accelerator is depressed in either reverse or any forward gear. No audible change to idle when the accelerator is depressed. THIS IS THE ISSUE I'D LIKE HELP WITH.
For poops and giggles I tossed in the spare ECU using its original EPROM. I'm pretty sure it's off a manual transmission K truck with the 6.5TD. All was the same EXCEPT:
* I noted a VERY SLIGHT increase in RPM when the pedal was depressed.
On the original ECU with the original EPROM I get the following data shown in GMTDScan Basic:
ECT 195*f
RPM~650
TDCO -1.5*
Pump Timing~26*
Desired timing 4.5*
Actual timing 4.5*
injection pulse 2.15ms
All is the same on the spare ECU with the spare (wrong) EPROM except:
I didn't check Pump Timing.
TDCO -0.7*
Idle was slightly higher at ~680 RPM.
I verified function of all three APP sensors in GMTDScan Basic against values in the GM "1994 C/K, G and P3 TRUCK DRIVEABILITY AND EMISSIONS (DIESEL) SERVICE MANUAL SUPPLEMENT" manual, which contains the factory specs for the APP voltages.
The only thing I can see that is NOT in line is the injection pulse, which appears to be about 0.20ms greater than the value specified in the manual. Can that cause the issue I'm seeing? It looks like others are shooting for 8.5* desired timing. I wouldn't think that the desired timing would change if I moved the IP timing but I haven't tried it. Could it be the weak cylinder DTC? Has anyone else had (and hopefully solved) this sort of issue? I have NOT performed TDC Offset. I bought the cable needed for GMTDScanTech but will only buy the software license if the free version won't do what I need to make this beast run correctly.
Thanks in advance for any suggestions. I'll be glad to fill in any missing data as soon as I can.
_________________________________
