TurboTahoe
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Hi guys!
I guess it's the Tahoe's turn to need some attention.
1) What say you to this?
2) Can the current APP (Accelerator Pedal Position) unit be tested?
I'm going to do the obvious and simply unplug the current APP and clean the contacts, re-plug it.
I see that Amazon has Delco APPs for around $200
Thanks for your time, you guys are the best!
-Rob
I might need to pick up my long-desired GMTDScan from Leroy. Does he no longer carry the cables?
Problem: Explain your problem in concise language (ie: Cranks but won’t fire): Engine stumbles at idle, "Service Throttle Soon" light turns on, engine continues to stumble while idling, ignores input to accelerator pedal. Shut rig down and parked for 20 minutes, then started and ran as normal.
Demographics: tell us about your truck and your ambient conditions: 45 degrees F. Clear and sunny.
- Year: 1995
- Truck model and class (ie: c2500) K2500
- Automatic or Standard: Auto
- Mileage: (indicate miles or km) 196,000 miles
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) : as seen in sig below: Remote Heath PMD, hogged out S intake with EGR delete, aftermarket chip.
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? S engine.
- Ambient outside temp: (indicate *C or *F) 45 degrees F.
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) #2 Diesel, ULSD
- What fuel additives are you using? Gallon of B99 (ASTM certified) per tank.
- Where are you located? Pacific NW, USA
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter: Good, 2 years ago, but only about 5000 miles
- Fuel filter: Good, 1 year ago, 3000 miles.
- CDR Valve? 3 years old.
- Coolant – last flushed/replaced at 2 years ago
- Oil – synthetic/regular, changed at: Change 1 month ago, running Mobil 1 Synthetic Turbo Diesel 5W/40
- Batteries – state of charge, (matched set) replaced at: Fully charged, changed 1 year ago.
- Battery cables and grounds (removed, cleaned and tightened): Checked, cleaned and tightened 1 year ago. All looks good.
- Glow Plugs - how many miles on them? 7000 miles What type? 60g
- Injectors - last changed at: Original to rig!
History: (Describe how the problem first appeared.)
- What were you doing when it happened? Came to stop on residential street, about to turn into the shopping mall.
- How was the truck running fine before this problem appeared? Yes! Strong, normal.
- 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) YES And? Did the paper clip thing, got the following codes:
DTC 23 = Accelerator Pedal Position (APP) 1 Circuit Range Fault
DTC 27 = Accelerator Pedal Position (APP) 2 Circuit Range Fault
DTC 84 = Accelerator Pedal Position (APP) Circuit Fault
Diagnostics:
1] Starting:
1a] Does the engine start? YES
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, 5-6 Seconds, normal time
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? NO
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) HEATH Remote
3b] Condition of Extension harness (if used) Vendor or Homemade? HEATH Remote
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. Looks good.
3d] PMD Make: HEATH Remote
3e] PMD Age: 8 years
4] Stalling Issues
4a] Do you experience stalling only when hot? Only happened once when hot.
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) Happened when coming to a stop.
4c] Does pouring cool water over the IP seem to help with restarting? Didn't try
4d] Is stalling momentary (engine recovers)? Appears to recover after stopping for a few minutes.
4e] Does SES light come on when engine hiccups? NO
4f] Does cruise control quit working when engine hiccups? UNKNOWN
4g] Does re-starting seem to reset engine, restoring cruise and power? YES
4h] Changes to dash lights or instruments during stalling events? Service Throttle Soon light turns ON.
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? NO (actually, after I did all the changes in my sig, I get VERY little smoke)
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)? ______________
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 guess it's the Tahoe's turn to need some attention.
1) What say you to this?
2) Can the current APP (Accelerator Pedal Position) unit be tested?
I'm going to do the obvious and simply unplug the current APP and clean the contacts, re-plug it.
I see that Amazon has Delco APPs for around $200
Thanks for your time, you guys are the best!
-Rob
I might need to pick up my long-desired GMTDScan from Leroy. Does he no longer carry the cables?
Problem: Explain your problem in concise language (ie: Cranks but won’t fire): Engine stumbles at idle, "Service Throttle Soon" light turns on, engine continues to stumble while idling, ignores input to accelerator pedal. Shut rig down and parked for 20 minutes, then started and ran as normal.
Demographics: tell us about your truck and your ambient conditions: 45 degrees F. Clear and sunny.
- Year: 1995
- Truck model and class (ie: c2500) K2500
- Automatic or Standard: Auto
- Mileage: (indicate miles or km) 196,000 miles
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) : as seen in sig below: Remote Heath PMD, hogged out S intake with EGR delete, aftermarket chip.
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? S engine.
- Ambient outside temp: (indicate *C or *F) 45 degrees F.
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) #2 Diesel, ULSD
- What fuel additives are you using? Gallon of B99 (ASTM certified) per tank.
- Where are you located? Pacific NW, USA
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter: Good, 2 years ago, but only about 5000 miles
- Fuel filter: Good, 1 year ago, 3000 miles.
- CDR Valve? 3 years old.
- Coolant – last flushed/replaced at 2 years ago
- Oil – synthetic/regular, changed at: Change 1 month ago, running Mobil 1 Synthetic Turbo Diesel 5W/40
- Batteries – state of charge, (matched set) replaced at: Fully charged, changed 1 year ago.
- Battery cables and grounds (removed, cleaned and tightened): Checked, cleaned and tightened 1 year ago. All looks good.
- Glow Plugs - how many miles on them? 7000 miles What type? 60g
- Injectors - last changed at: Original to rig!
History: (Describe how the problem first appeared.)
- What were you doing when it happened? Came to stop on residential street, about to turn into the shopping mall.
- How was the truck running fine before this problem appeared? Yes! Strong, normal.
- 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) YES And? Did the paper clip thing, got the following codes:
DTC 23 = Accelerator Pedal Position (APP) 1 Circuit Range Fault
DTC 27 = Accelerator Pedal Position (APP) 2 Circuit Range Fault
DTC 84 = Accelerator Pedal Position (APP) Circuit Fault
Diagnostics:
1] Starting:
1a] Does the engine start? YES
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, 5-6 Seconds, normal time
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? NO
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) HEATH Remote
3b] Condition of Extension harness (if used) Vendor or Homemade? HEATH Remote
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. Looks good.
3d] PMD Make: HEATH Remote
3e] PMD Age: 8 years
4] Stalling Issues
4a] Do you experience stalling only when hot? Only happened once when hot.
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) Happened when coming to a stop.
4c] Does pouring cool water over the IP seem to help with restarting? Didn't try
4d] Is stalling momentary (engine recovers)? Appears to recover after stopping for a few minutes.
4e] Does SES light come on when engine hiccups? NO
4f] Does cruise control quit working when engine hiccups? UNKNOWN
4g] Does re-starting seem to reset engine, restoring cruise and power? YES
4h] Changes to dash lights or instruments during stalling events? Service Throttle Soon light turns ON.
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? NO (actually, after I did all the changes in my sig, I get VERY little smoke)
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)? ______________
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.
