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6.5 poor fuel milage and random missfire

Streetrodder

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Location
Illinios
Problem: Explain your problem in concise language (ie: Cranks but won’t fire). _____________poor fuel milage random misfire_______________

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

- Year: ___1995___
- Truck model and class (ie: c2500) ____suburban k2500_____
- Automatic or Standard __auto________
- Mileage: (indicate miles or km) ____252,000_____
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) _____IP, Injectors, e-prom chip, pmd, lift pump, cold air intake, turbo master, water pump, clutch fan, fuel filter, electronic filter harness______
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? _______F turbo_______
- Ambient outside temp: (indicate *C or *F) _____30F_____
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _____BP #2____
- What fuel additives are you using? _____power service______
- Where are you located? _____illinios________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter ____246,000_____
- Fuel filter ____250,000_____
- CDR Valve? ____246,000_____
- Coolant – last flushed/replaced at ______246,000_______
- Oil – synthetic/regular, changed at _____rotella synthetic 250,000______
- Batteries – state of charge, (matched set) replaced at _____248,000 5mo old________
- Battery cables and grounds (removed, cleaned and tightened): ____246,000__________
- Glow Plugs - how many miles on them? ____10,000_____ What type? _____________
- Injectors - last changed at ________2,000_miles ago______


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) __y__ And? ____none____


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? _________
1f] Does your glow plug light come on? ___yes______ For how long? _____about 45 sec____
1g] Do you see smoke from the exhaust while cranking? What color? ________
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? ______yes______
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? ___yes about 3/4 gallon in 2 minutes______
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? _____yes______

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) ____new one now on pump have one for intake no differance_______
3b] Condition of Extension harness (if used) Vendor or Homemade? _________
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. ___good______
3d] PMD Make: _____standadine, _ss diesel suply_____
3e] PMD Age: ______standadine 1 week ssds 1.5 years_______

4] Stalling Issues
4a] Do you experience stalling only when hot? ______yes______
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ____on eccel__
4c] Does pouring cool water over the IP seem to help with restarting? _________
4d] Is stalling momentary (engine recovers)? _____yes____
4e] Does SES light come on when engine hiccups? _____no____
4f] Does cruise control quit working when engine hiccups? _____no______
4g] Does re-starting seem to reset engine, restoring cruise and power? ____NA_____
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? _____no_____

6] Performance Issues
6a] Do you have gauges (boost, EGT) ? ____boost_______
6b] Maximum boost under load? ____15psi________
6c] Have you added a performance PCM (reflash) or Chip? _____heath e-prom econimy_________
6d] Have you changed exhaust / downpipe / crossover? _______3in down, 4in back baffle style muffler, heath crossover_________
6e] Wastegate – mechanical or vacuum (OEM)? ______mechanical________

7] Temperature-related Issues:
7a] Single or dual thermostats? ______single______
7b] Have you replaced them lately? Manufacturer of replacements? _____246,000____
7c] Have you pulled and cleaned Radiator and coolers lately? ______246,000______
7d] Have you replaced the fan clutch? Manufacturer of replacement? ___246,000 heath deisel_____
7e] (winter) Have you tested your antifreeze? Good to what temp? ___-30_______
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.

_______________truck was given to me with 240,000 miles had no power relaced a lot of parts. Now it will pull 8000lbs enclosed now prob but only 8mpg. 15mpg no trailer on hwy. tired of spending money and havingpoor fuel milage and missfir please hel__________________
 
Welcome to TTS.

What have you done? What have you noticed? Any recent changes?
I do see you have a new PMD. Does the misfire happen with new PMD? You need to remote mount that out of engine compartment ASAP.
What Tstats you run? What axle ratio?
Did you install new injectors? its recomended @ 100k.
 
Thanks for responding, I have replace Injection pump, Lift Pump, cold air intake, water pump, t stat, fan and clutch, eprom, Injectors, cross over pipe, electronic filter harness,and cdr valve all from heath deisel also I change fuel filter every oil change every 4000 to 5000 miles. always had no power and bad milage sence i got it 8 months ago now has plenty of pulling power but bad mpg and a miss i cant get rid of. truck has 4:11 gears bill Heath said the worst I should get pulling a house through the rockies would be 11mpg please helllllp.
 
IP is new not rebuilt bought it from heath deisel installed it last weekend set tdc off set to -1.74 truck ran good for a few days then misfire is slowly coming back. misfire happends with both pmds. tstat temp is 195. I found this check list on this forum one question ask do you hear a vacum when you remove fuel cap. I do hear a pretty heavy vacume is this normal or could this be starving my truck for fuel?
 
You think I have the wrong fuel cap? Is there a vent in the tank? I guess a vacume is not normal. Just looking at all possibilities. I have invsted alot of time and money to still have the same problems.
 
From my experience. I would check the fuel pressure under WOT in park. You are looking for a restricted fuel screen in the fuel filter manager, on the Injection Pump, or the tank sock being plugged. The hiss on the tank can starve you for fuel. You also should put a clear return line on the IP and check for air bubbles as this will also give you a fish bite, random miss.

You can get as low as 7 MPG towing - been there done that got the t-shirt and failed business from it. The real problem for MPG when towing or under a load is the restrictive GMx turbo. As Heath Diesel sells a Turbo Master and GM8 turbo their advice is around what they sell. After swapping turbo's to the A Team Turbo I went from the 7 MPG in the heavy mountain passes to double digit 10.4 MPG towing.

In depth is here:

http://www.thetruckstop.us/forum/showthread.php?32683-Payson-AZ-Turbo-pull-off-*Round-1*
http://www.thetruckstop.us/forum/showthread.php?32658-Results-of-using-an-A-Team-Turbo
 
I will try to leave fuel cap loose for a tank full good idea. I replaced the injectors about 2000 miles before the pump same problem before and after. New injectors are new boch not reman. I will check for presure at WOT tomorrow. What should it be? Is the return the short hose at top of pump? I will change it out for a clear one. Is there a vent on the tank and were is this sock? Turbo is making 15lbs of boost im good with how the truck pulls just wish it ran better. I will post results tomorrow thanks for all the great suggestions.
 
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