Hello everyone -
I bought my first GM product back in July, a 1993 GMC 3500 with a 6.5 diesel. My other truck is a 1993 Ford with a 7.3, naturally aspirated. It's a great truck with only 80,000 miles. I've had it for 3 years with no problems, and was happy to find a diesel powered second truck with the budget I had in mind. It also seems to be a very solid, older truck, even though it has a jillion miles.
The problems with the GMC started within days of buying it. It will start in the morning, although not as fast as it should, but after getting to operating temperature, then being turned off and left sitting for half an hour or so, it becomes very difficult to start. When it finally does start, a big cloud of grey smoke comes out. It was 35 degrees F this morning, and it started, so the gp circuit works for now, though when it gets really cold I'm not sure the batteries are going to have enough zing, even though they're less than a year old.
What I've done so far........
1. Checked the glow plug resistance; replaced two (including #8). Could not get to #6. The other five Ohmed around .8-1.4 to the negative pole of the battery. The two that were replaced were open.
2. Did the "lift pump test" and verified it works while running. Also pulled the plug at the pump, verified proper voltage, and felt the lift pump with plug attached. It's definitely thumping, though I can't hear it.
3. Purchased through E-bay the "6.5 Liter V-8 Turbo Diesel Engine" book, GM publication 16015.12.2. Though not an indepth shop manual, it's actually a student workbook, it seems to have enough information and detail to serve as a good foundation.
4. Reviewed both the glow plug and lift pump wiring information found in above reference.
A few questions to the group:
1. When warm, the glow plugs do not come on (they do on the Ford every time it's started, regardless). The wiring diagram in the book does not indicate any kind of thermal input device, i.e. temperature switch, etc. There are four wires to the controller, none of which are temperature dependent. Is there an internal thermal control in the glow plug controller, or is something flaky with the way it's acting?
2. Where exactly is the lift pump control relay located?
3. I put a clamp on amp meter around the glow plug relay leads, and also around a single wire going to a glow plug, but got nothing at either place. I don't know if this type of meter will work on DC current. What type of amp meter can be used to test if current is actually passing through leads?
4. One other thing, I noticed the engine ground strap to the frame by cylinder #8 is broken. What is the implication for this?
5. Am I on the right track here, should I go in a different direction, or does this dragon have many heads?
The truck has 305,000 miles. The previous owner put 50,000 on it in two years, and did not talk like he did anything other than drive it, so I have no information regarding other repairs, and replacements over the life of the truck.
Thanks in advance for any help that might be offered, and sorry for such a long, first post.
And here's the diagnosis check list..........
- Year: -1993
- Truck model and class (ie: c2500) -GMC 3500
- Automatic or Standard - Auto
- Mileage: (indicate miles or km) 305,000
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc)- none ___________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? - 6.5 TD
- Ambient outside temp: (indicate *C or *F) 60-90F
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) - #2 _________
- What fuel additives are you using? None
- Where are you located? Kansas
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter - unknown
- Fuel filter _________ - unknown
- CDR Valve? _________ - unknown
- Coolant – last flushed/replaced at _____________ - unknown; I added about two quarts, but it disappeared; does not have gunk in radiator, and did not see it leak out
- Oil – synthetic/regular, changed at ___________ - regular; change recently
- Batteries – state of charge, (matched set) replaced at _____________ - two 850 cca, each less than one year old
- Battery cables and grounds (removed, cleaned and tightened): good ______________
- Glow Plugs - how many miles on them? _________ What type? unknow _____________
- Injectors - last changed at _______________ unknown
History: (Describe how the problem first appeared.)
- What were you doing when it happened? ______________
- How was the truck running fine before this problem appeared? truck runs and drives good once started, no misses, stuttering or anything
- 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? Auto store showed me how to stic clip in and get codes; none came up ________
Diagnostics:
1] Starting:
1a] Does the engine start? _________ yes, but cantanquerous when warm
1b] Does the engine crank over? ________ yes
1c] Are your batteries fully charged? _________ yes, they don't seem to have as much juice as they should, though
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; 10 seconds or so
1f] Does your glow plug light come on? yes For how long? 10 seconds or so
1g] Do you see smoke from the exhaust while cranking? What color? a little, kind of grey
1h] Does the Service Engine Light Glow during Start/bulb check? ________
2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____________ no but test indicates it is
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? _________
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? ____________ 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? Haven't tried that _________
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? _______ it gets pressure
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 really
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? ______________ no
6d] Have you changed exhaust / downpipe / crossover? ________________ no
6e] Wastegate – mechanical or vacuum (OEM)? ______________ unknown
7] Temperature-related Issues:
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? __________
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 bought my first GM product back in July, a 1993 GMC 3500 with a 6.5 diesel. My other truck is a 1993 Ford with a 7.3, naturally aspirated. It's a great truck with only 80,000 miles. I've had it for 3 years with no problems, and was happy to find a diesel powered second truck with the budget I had in mind. It also seems to be a very solid, older truck, even though it has a jillion miles.
The problems with the GMC started within days of buying it. It will start in the morning, although not as fast as it should, but after getting to operating temperature, then being turned off and left sitting for half an hour or so, it becomes very difficult to start. When it finally does start, a big cloud of grey smoke comes out. It was 35 degrees F this morning, and it started, so the gp circuit works for now, though when it gets really cold I'm not sure the batteries are going to have enough zing, even though they're less than a year old.
What I've done so far........
1. Checked the glow plug resistance; replaced two (including #8). Could not get to #6. The other five Ohmed around .8-1.4 to the negative pole of the battery. The two that were replaced were open.
2. Did the "lift pump test" and verified it works while running. Also pulled the plug at the pump, verified proper voltage, and felt the lift pump with plug attached. It's definitely thumping, though I can't hear it.
3. Purchased through E-bay the "6.5 Liter V-8 Turbo Diesel Engine" book, GM publication 16015.12.2. Though not an indepth shop manual, it's actually a student workbook, it seems to have enough information and detail to serve as a good foundation.
4. Reviewed both the glow plug and lift pump wiring information found in above reference.
A few questions to the group:
1. When warm, the glow plugs do not come on (they do on the Ford every time it's started, regardless). The wiring diagram in the book does not indicate any kind of thermal input device, i.e. temperature switch, etc. There are four wires to the controller, none of which are temperature dependent. Is there an internal thermal control in the glow plug controller, or is something flaky with the way it's acting?
2. Where exactly is the lift pump control relay located?
3. I put a clamp on amp meter around the glow plug relay leads, and also around a single wire going to a glow plug, but got nothing at either place. I don't know if this type of meter will work on DC current. What type of amp meter can be used to test if current is actually passing through leads?
4. One other thing, I noticed the engine ground strap to the frame by cylinder #8 is broken. What is the implication for this?
5. Am I on the right track here, should I go in a different direction, or does this dragon have many heads?
The truck has 305,000 miles. The previous owner put 50,000 on it in two years, and did not talk like he did anything other than drive it, so I have no information regarding other repairs, and replacements over the life of the truck.
Thanks in advance for any help that might be offered, and sorry for such a long, first post.
And here's the diagnosis check list..........
- Year: -1993
- Truck model and class (ie: c2500) -GMC 3500
- Automatic or Standard - Auto
- Mileage: (indicate miles or km) 305,000
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc)- none ___________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? - 6.5 TD
- Ambient outside temp: (indicate *C or *F) 60-90F
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) - #2 _________
- What fuel additives are you using? None
- Where are you located? Kansas
General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter - unknown
- Fuel filter _________ - unknown
- CDR Valve? _________ - unknown
- Coolant – last flushed/replaced at _____________ - unknown; I added about two quarts, but it disappeared; does not have gunk in radiator, and did not see it leak out
- Oil – synthetic/regular, changed at ___________ - regular; change recently
- Batteries – state of charge, (matched set) replaced at _____________ - two 850 cca, each less than one year old
- Battery cables and grounds (removed, cleaned and tightened): good ______________
- Glow Plugs - how many miles on them? _________ What type? unknow _____________
- Injectors - last changed at _______________ unknown
History: (Describe how the problem first appeared.)
- What were you doing when it happened? ______________
- How was the truck running fine before this problem appeared? truck runs and drives good once started, no misses, stuttering or anything
- 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? Auto store showed me how to stic clip in and get codes; none came up ________
Diagnostics:
1] Starting:
1a] Does the engine start? _________ yes, but cantanquerous when warm
1b] Does the engine crank over? ________ yes
1c] Are your batteries fully charged? _________ yes, they don't seem to have as much juice as they should, though
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; 10 seconds or so
1f] Does your glow plug light come on? yes For how long? 10 seconds or so
1g] Do you see smoke from the exhaust while cranking? What color? a little, kind of grey
1h] Does the Service Engine Light Glow during Start/bulb check? ________
2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____________ no but test indicates it is
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? _________
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? ____________ 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? Haven't tried that _________
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? _______ it gets pressure
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 really
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? ______________ no
6d] Have you changed exhaust / downpipe / crossover? ________________ no
6e] Wastegate – mechanical or vacuum (OEM)? ______________ unknown
7] Temperature-related Issues:
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? __________
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.
, just got a quote from Phillip (pres of Pensacola Diesel), After a little going back and forth with e-mail regarding if the IP was on their site he finally said "the pump is not on our site, the 6.5 db2 is offered 2 ways , a reman head & rotor 495.00 & a new head & rotor is 695.00"
