Symptoms of bad or Gelled fuel

Discussion in 'GM 6.5 Diesel Engines' started by iamdave0887, Jan 3, 2010.

  1. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Hey guys.

    My father borrowed my truck one day to haul a load of firewood. He put fuel in it beforehand.

    What are the symptoms of bad fuel or gelled fuel?

    Right now i've got a P0251 and P0370, which Bill Heath says when those together pop up it indicates a bad LP. The LP was warrantied out not 2-3 weeks before all this started and it has great flow and pressure. The warrantied one had great fuel flow and pressure afterwards i found out, and my fuel psi gauge was bad and maxing out at only 4 psi. I thought it was bad because i had gotten a P0251 and P0370 on the ride back from a large parts run two states over to Massachusetts a few months ago. Swapping the LP made the codes go away and stay away.

    along with the two above codes i get extended cranking to start the truck, outside and engine temperature doesn't matter. Once the engine is running the idle will lope from 900 to 400 all on it's own, all the while puking black smoke from the exhaust. Sometimes it'll lope once or twice and clear up and run fine, other times it'll lope for what seems like eternity, but it'll always clear up and run fine afterwards. Other symptoms include Coughing, sputtering, misfiring all during the time the engine is loping, and it's even died altogether a few times on me.

    Strange thing is this comes and goes. When it runs fine it runs perfect. I tested to see if it was a fuel supply issue by heading to the mile and 1/2 long 6% or so grade by my place. I started at the bottom of the hill and kept the go pedal pinned the entire time. Pushing 15 psi boost and running with full power up the hill. It ran perfect, no coughing, nothing. Then about a mile later, the symptoms showed back up again, along with the check engine light and a change in the diesel rattle. I promptly shut the engine off and restarted it, and the extended cranking and loping idle were back as well. The loping idle and coughing/etc is only when starting the truck. Once running it's fine. It passed the hold at 2K RPM test as well. All the symptoms come and go at the same time.

    Could this be bad fuel? New fuel filter was installed the first day this started. No change. No WIF light. Added 1/2 a bottle of Power Service white bottle and 2-stroke oil, cleaned up battery connections and grounds and nothing seems to have helped.

    Could my IP be dying? The truck has 188K on it with evidence that the IP was changed before by a dealer but i've no idea what mileage it was changed at.

    I'll get a video once the freezing cold winds and snow dies down a tad.

    Thanks guys,

    - Dave
     
  2. Dave01

    Dave01 New Member

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    I doubt its bad fuel, you'd have the trouble all the time, not some of the time and other times perfect. Just for a check, run a cup of fuel out of the t-valve just to see what it looks like. Also doubt its gelled fuel, once running you've got a heated filter manager plus heated fuel return-to-tank. Have you added any bio-diesel recently? If so, then I might suspect junk or gelled fuel.

    If your IP passed the hold 2,000 test (I assume it also passed the ramp it down slow from 2,000 test) it hopefully rules out the IP as well.

    If fuel delivery seems OK, an intermittant problem like that is probably electrical. You've checked grounds and battery connections, but how about the batteries themselves? Are they OK, each putting out the proper 12 plus volts? Are you seeing 14 plus volts when running?

    My quick guess is PMD. Do you have a known one you can try to prove this out?
     
  3. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Haven't tried the down from 2,000 RPM test yet. Will try that now. I have a Midtronics carbon pile load tester here as well as a Midtronics Handheld battery/starter/alternator tester. Both testers confirmed that the batteries were both good and had over 900CCA's each. They are rated for either 800 or 880 CCA. Can't remember now.

    Don't think i've run any Bio-D lately, unless it was blended in with the regular pump diesel. There's no stations that i'm aware of, or at least that i go to, that carry Bio-D.

    I hope it's not a PMD. It's the Heath Isolator kit. Could be...

    Strange that once it's running it's fine save for the SES. Shut it down and bang it's back to it's crap.

    This is so frustrating.....
     
  4. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Just did the down from 2,000 RPM test. That's fine too.

    No SES light when i went out now. I've got the block heater plugged in to see if engine warm or cold matters.

    Not sure what else i can test.....
     
  5. 97duallydiesel

    97duallydiesel New Member

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    Dave , i feel your pain man.. I'm having similiar problems :mad2:Steve
     
  6. SmithvilleD

    SmithvilleD Member

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    I'm guessing you don't have a fuel pressure gauge?

    Reason I asked is last night I drove my truck 250 miles in the coldest temps so far on the new engine/setup. -10 F at startup. Fuel got a shot of the white/winter bottle Power Service additive at the pre-trip fillup. I'd expected the cold temps before leaving my somewhat warmer MO home temps before heading up to IA. So I'd swapped my Racor pre-lift pump 10 micron filter back to the 30 micron. Glad I did.

    My mechanical fuel pressure gauge shows each pulse from the Walbro pretty crisply. & that lessens when you're on it hard enough fuel demand goes up.

    Last night at -10 F startup, watching the fuel pressure gauge made it easy to envision the pump was pushing syrup instead of low viscosity fuel. Much slower pulsing & the pressure at normal hwy cruise load was a couple psi lower.

    On the 250 mile drive back to MO, I felt fishbites numerous times. Seemed to typically be at mid-load but not necessarily getting worse as load went up/fuel pressure went down. Don't know if it might be sucking air in somewhere pre-lift pump when cold causes fuel viscosity to go up?

    Don't know if your situation could possibly be related as you mention it happening at different outdoor & engine temps? Just thought I'd share as I'd guess you're getting colder temps now as well.
     
  7. 94K30

    94K30 Diesel nut

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    might sound too simple, Dave, but how is the fuel filter?
     
  8. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    The filter in there is a week old if that. The old one was dirty, but it wasn't the worst fuel filter i've pulled from that truck.

    I've no idea what's going on. Went outside again to disconnect the block heater in both trucks as i've got no where to go tomorrow morning and tried the pickup again. Fired right up and ran perfect. :mad2: I don't get it what am i missing?
     
  9. Dave01

    Dave01 New Member

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    One more thought - air leak somewhere. That would let fuel bleed down causing the long cranking, would also cause hiccups and uneven idle. Not sure why it would go away at times though ......
     
  10. ak diesel driver

    ak diesel driver Active Member

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    Put a fuel pressure guage on it so we can tell if it's a fuel issue or electrical
     
  11. buddy

    buddy New Member

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    Sounds like contaminated fuel, or lack of fuel pressure. Do you know how to do the LP diagnostics for you truck to check that its all functioning? Does it work with just Ignintion On during WTS?

    Have you looked at the IP lately? Are the 3 nuts still on there? Its probably your timing, or related to the Coolant temp sensor. Starts fine with block heater, how long is your preglow?

    Do you know how to check and change the timing? Id check what the TDCO value is, then run the KOKO procedure and see what it is afterwards.
     
  12. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Glowtime is quite long due to the GL4. Last time i counted the GP light was on for 7-8 seconds.

    Timing should be good. TD set it but his scanner didn't like my truck so i had to check it w/ a tech II at my college. Came up as -0.90 then.

    The LP runs on WTS, and with the engine running. I get plenty of fuel from the water drain with the engine running and it doesn't stall. I do know how to do the LP diagnostics, just have to borrow my friends pressure gauge, mine's busted.

    Could the optic sensor be going? i did remove the OS filter harness a while back(maybe a year ago or close to it) as it was going bad, and causing issues.

    The more i sit here and think about it the more i think it's contaminated fuel. The OS has to see through the fuel, and if it's cloudy it can't. My blazer has fuel from the same station in it but the DB2 doesn't have any sensors in it that have to see through the fuel so it just burns it.

    Hmmmm....time to take a fuel sample i think.
     
  13. SmithvilleD

    SmithvilleD Member

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    Were the issues happening before the recent fuel filter change?

    Also might try cracking the water in fuel/filter mgr drain valve (while the lift pump is running) & see what comes out?
     
  14. guybb3

    guybb3 Member

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    Dave, I went through EXACTLY what you are experiencing now and it was bad fuel. It took a couple of tanks and fuel conditioner to clear it out. I just came home from seeing your thread on the other site a couple of hours ago and the more clues you give, the more it is identical to my problem a year ago. The only caveat is that on my last tank (that cleared the problem) I also changed both batteries that were getting a tad weak, so I'm giving you ALL the facts.
     
  15. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    This all started after my father put fuel in. He said it ran fine when he went to haul a load of wood that day. I changed the fuel filter the next when it first started acting up on me. The old filter didn't look terrible. I've pulled worse looking filters from the FFM. New filter didn't change anything.

    I've got a bottle of Diesel 911 that i'm going to dump in now. Going to see if that helps.
     
  16. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Interesting. Yours even did the hard starting and coughing thing and sometimes ran perfect? I can't se a bad IP running perfect one second and then running like total :shiiiiiite: the next second.

    I really pray this is bad fuel and not the IP going south on me.

    Still can't get this issue on video. Off camera the truck's being a PITA but on camera it's a saint. :pissed:
     
  17. guybb3

    guybb3 Member

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    Yes. Mine seemed to limp after I would start it up warm. If I let it cool overnight, it would start loud as hell and then run fine. The second I shut it off warm and started it again it would limp and run like crap. I had codes 0251 and 0370 also.
     
  18. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Interesting. mine starts hard most of the time, yet sometimes it'll fire up and run fine with no codes. it's always puking up 0251 and 0370 but a new one popped up today. Crankshaft position sensor. :mad2: Can't remember the code number. Something about Crankshaft position sensor circuit A. Seem like random sensors all over are freaking out. The CPS wouldn't be affected by bad fuel, unless all the cranking coughing loping and misfiring is driving the sensor nuts?

    If this is bad fuel it's an extreme case of it it seems. Stupid truck....I drive it to work...it drives me to drinking.....:mad2:
     
  19. Dave01

    Dave01 New Member

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    Dave, I suggested yesterday you draw a cup of fuel off the t-valve, and you mentioned it in another post. It takes only a minute, and you keep wondering about the fuel, so why not run outside right now and take a look? I'm curious too, would be nice to find out if it looks dark or cloudy or has water droplets in it.
     
  20. iamdave0887

    iamdave0887 Here Comes Chaos.....

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    Damn....I knew i forgot to reply to one post.

    I did this. Filled an old clear container with Diesel. Fuel is clean looking and i see no water in it. It's not cloudy what-so-ever. Its a yellowish-blue and i can see through it. The fuel is still sitting in the same container outside in my garage. It's about 20*F here. Wheni last checked it it didn't seem gelled at all.

    I've got no idea what's wrong with this damn thing. Hell the truck doesn't even know whats wrong with itself.

    Todd from heath diesel seemed surprised today on the phone when i said that it passed the up to and hold at 2K RPM test and it passed the down from 2K to idle test. Even with the SES on and it starting like crap and loping at idle it still passes those tests. Smooth up and down with the throttle. Hardest part is not moving my foot too fast as the throttle in that truck has always been very sensitive.

    Could a bad OS cause this? Maybe a bad Crank sensor but then i would've gotten a crank sensor could from the get go not the 0251 and 0370 that's always popping up.

    I just don't understand how it can start god awful and lope like mad and then other times it'll fire up like nothings wrong at all.
     

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