LBZ Power Loss

Discussion in '06-07 LLY/LBZ' started by BigDogYJ, Sep 16, 2009.

  1. BigDogYJ

    BigDogYJ Recruit

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    ok so I am going to make this short...

    I have been experiencing power loss while accelerating over the past few weeks. I noticed it when accelerating onto the freeway. It feels like im letting off the throttle even though I am obviously not. it will usually do this for a few seconds and sometimes the power comes in and out then finally starts acting normal and accelerates like a raped ape.

    No CEL or codes in ECM.
    I figured I had a plugged fuel filter. Just got back from a 2500mile trip and figured I may have picked up a bad batch of fuel. I just changed the filter last night. After I changed it I went out and drove it and it ran fine so I figured all was good. Then today I was driving around. I have maybe 50 miles on the new fuel filter and it started acting up after a 15 mile drive at ~ 70MPH and when I start accelerating from a red light it starts acting like I am bouncing the throttle then starts taking off after a few seconds.

    I am stuck. I have read about the turbo vane position sensor, but I am not getting any codes whatsoever. I cant seem to duplicate the issue now, but I have my edge insight set to show turbo boost and fuel pressure so when it starts acting up I can at least keep an eye on those.

    If you have any insight, it would be greatly appreciated. I had the trailer on last weekend and it started acting up trying get on the freeway (not a good feeling).

    Thanks guys..
     
  2. btfarm

    btfarm Quarter Million Worth Staff Member

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    IIRC, it will defuel at shift approach through the first 3 gears under hard acceleration if not in tow/haul. Something like that... But it shouldn't stumble, just bog down a bit.
     
  3. t2ch

    t2ch New Member

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    Have you tried returning to the stock tune?
     
  4. Wrecker

    Wrecker The Oil Geek

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    Electrical plug on the air filter/intake making good contact?
     
  5. BigDogYJ

    BigDogYJ Recruit

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    I know its supposed to defuel but this is happening at 30% throttle. It never happened before like that. I used to be able to practically floor it if needed and never lost power or defuel. also, it does the same things in Tow/Haul sometimes I can get it to happen more often in Tow/Haul mode.
     
  6. BigDogYJ

    BigDogYJ Recruit

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    Yup returned it to stock and still happened. That was the first thing I did when I noticed it and after it kept happening when stock, I figured it was the fuel filter.
     
  7. btfarm

    btfarm Quarter Million Worth Staff Member

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    Does this happen at stock tune?
    On edit, I see Travis beat me to it.
     
  8. BigDogYJ

    BigDogYJ Recruit

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    I have not checked that yet. I do have the fingerstick on there. and its possible that the connections may have come loose. I will check those tonight. Thanks.
     
  9. Sparky8370

    Sparky8370 Do chickens have large talons

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    I have been having the same sort of problems with my 01. Every time I change my fuel filter it gets better for a little while. I have cut a few of them apart and they look just like the one that I changed after 20-25k miles. I went through 5 of them in 1000 miles, and another 2 since. I got into a bad batch of fuel I think.
    If it gets better after you change the filter, than it must be fuel related. At least that's my thoughts on mine. Either bad fuel, or the filter is creating just enough restriction to slow down an ailing cp3. I may just save up and get a modified cp3, and if that doesn't work I will clean the tank. But, it's a great excuse to get one.
     
  10. GMCYA

    GMCYA Resident Coonass

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    I agree with Jay. Change the filter again and cut it open. See if it runs better for a day or so 'till the new one plugs again. One bad batch of fuel is a nightmare especially if it came from a tank with algae in it. If the filter you just put on is already dirty start looking in the tank. It is hard to dilute a bad batch even with 4-5 tanks of good fuel.
     
  11. btfarm

    btfarm Quarter Million Worth Staff Member

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    Good call guys. I know it took 4 filters last winter/spring to clear up 1 gelled batch of fuel. $130 worth of filters and of course the manager of the offending Pilot station had no idea what I was talking about... "nobody else gelled, must be your truck!"
     
  12. blksmok

    blksmok Don't listen to me.

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    When you changed the fuel filter, did it prime right away or did you have to pump it 'till your arm fell off. Likewise, once fuel squirted out the bleeder screw and you tighten it, did you pump it until it got hard and how long did that take?

    Reason I ask is the fuel filter head assembly has been known to develop a leak on the LBZ's and cause air to get sucked in. The symptoms are exactly as you describe and will only get worse until one of those flutters kills the engine and it won't restart because you can't prime the fuel system any longer. The air leak is too big eventually.
     
  13. Unit453

    Unit453 Cruises comfortably at 140... Staff Member

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    Is there a TSB for that? I havent heard a thing about it.
     
  14. BigDogYJ

    BigDogYJ Recruit

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    Ok. So I have a fingerstick on there. However, when I remove the PPE tune, the EGR code still gets set and turns on the CEL. So I have a feeling the Fingerstick is either not working or messing with something. I am going to remove it tonight, clean the air filter and check the MAF to make sure its not dirty.

    I dont think its a fuel problem. Today I noticed that I have plenty of power and no issues above ~50mph. From 0-40mph is where it happens the most. Also seems to happen when its warm outside (70-90F). in the evenings and at night I cannot reproduce it.
    Also, when I had it happen today getting off at the same exit as the other day I went to go accelerate and the turbo boost dropped to about 5psi and EGT's kept climbing but my speed hardly increased. No smoke at all until the boost psi jumped to 15 and it took off like a rocket with a fuel spots of hesitation (each time, the psi would drop and EGT remained the same or increased slightly.

    I am also interested in more info about the loss of prime. I did not have a problem with priming after the filter change. No starting issues. Fires right up first crank.
    Since I am seeing the EGT increase then I would believe that fuel is still flowing.

    Thanks guys.
     
  15. btfarm

    btfarm Quarter Million Worth Staff Member

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    THAT'S real damn interesting! I, also, had never heard that...
     
  16. Sparky8370

    Sparky8370 Do chickens have large talons

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    That is weird. I wonder if the drop in PSI and the EGR coding have something in common, like a cause for the loss. If your EGT's are climbing you must have enough fuel to make the boost, and if it's an intermittent loss it can't be an intercooler tube. I wonder if there is something wrong with your tune, or maybe a bad turbo or that the EGR is opening/leaking somehow?
     
  17. t2ch

    t2ch New Member

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    If the finger stick is not hooked up properly than I would say he has a loose connection in the finger stick connections.
    Is the AFE intake a dry filter? If not clean the MAF sensor in the intake tube.
     
  18. BigDogYJ

    BigDogYJ Recruit

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    So I cleaned out the air filter really good and cleaned the oil residue on the MAF sensor and for the last 2 days she hasnt acted up at all. Hopefully that was it. I have had bad shifting from having a dirty air filter before also. amazing what the Air filter can do. Hopefully that was the problem. I havent touch the Fingerstick yet.

    Thanks for all the tips guys. i'll let you know later this week if it comes back or not.
     
  19. t2ch

    t2ch New Member

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    Still running good? Did the MAF cleaning fix your problem?
     
  20. BigDogYJ

    BigDogYJ Recruit

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    So far so good. I gave a good run today and not a single hiccup. At this point, I am considering it resolved. All due to some lack of PR on my part. Shame on me...
     

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