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??TRUCK STILL RUNNING ROUGH..I'M GOING CRAZY..

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bckinblk, Jun 25, 2003.

  1. bckinblk

    bckinblk 1/2 ton status

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    ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    In my previous post I tried numerous things to get my 88 to run right but still no luck ..This is what I have replaced so far .
    IAC
    EGR
    EGR SELONOID
    TPS
    PCV VALVE
    FUEL FILTER
    1 YEAR OLD FUEL PUMP
    COOLANT TEMP SENSOR
    MAP SENSOR
    PLUGS
    WIRES
    CAP
    ROTOR
    ..After replacing these parts the truck idle has improved greatly but when I first start it it has a shaking stumble to it . After it is hot it runs like brand new at times but if I shut it down for even a minute it will run rough again until it gets hot ..It is not throwing any codes .I am at a loss ..I will try o2 sensor next (4 months old).Please if anyone has had these symtoms How did you fix ?? thanks in advance for any info..... /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif
     
  2. Confedneck

    Confedneck 3/4 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    are the plugs gapped correctly? does that thing have a mass air flow sensor?
     
  3. bckinblk

    bckinblk 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    No it is a MAP sensor .I know it is good .Can a fuel pump on its way out cause this?? But it runs good at times then it runs bad..I dont know what happened it just started doing it one day and since then I can't figure it out..Thanks again
     
  4. Confedneck

    Confedneck 3/4 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    hows the timing? check for vacuum leaks? im at a loss.... its really hard to do this over the computer...but my toyota has the same problem, idles a little rough and i know its vacuum and a slight exhaust leak and with the turbo on it its trouble... keep kickin around and look at vacuum hoses, EGR stuff and timing...
     
  5. bckinblk

    bckinblk 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    Timing is good and I have no vac leaks .?? I appreciate the help dude thanks.
     
  6. RockyRider13

    RockyRider13 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    It looks like you've spent a lot of money trying to fix this. Spend the bucks on a scanner that will read out the sensor outputs before you spend anymore money.

    If I were to make a guess, I'd say that you are getting either a rich or lean situation, making the truck run like crap until it gets into closed loop. Check the injector spray pattern to make sure it looks like a fine mist in a cone shape.
     
  7. sdavid

    sdavid 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    Check to make sure the O2 sensor connector is plug together good and no plug wires have vibrated loose. My K5 had a rough idle and a little stumble when cold and I changed the O2 and found that it was barely clipped together. I also found that a couple of wires were barely hanging on to the spark plug, so I squeezed them down and got them to snap back on properly. Make sure none of the sensor wires are frayed and grounding out anywhere. You have probably already done all this, but the simple things are sometimes overlooked. Good luck.
     
  8. bckinblk

    bckinblk 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    Today I swapped o2 sensor .I put in new vac hoses and cleaned the entire engine to look for any leaks and nothing .The truck is improving slowly but still is'nt 100% .But I did notice that the absolute manifold pressure hose was frayed and dryrotted .So I replaced it .Then I unplugged the battery for a relearn .When I started it it ran mint for about 2 minutes .But then the sputter slowly came back??? So far I am into it for about $200 thanks to lifetime parts and reciepts that I kept (thank god) My next investment will probably be a scanner .I will keep yous posted...Thanks for all the help /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/angryfire.gif
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    If you've got a laptop (or in a pinch, a really long cable : ) winALDL is a lot cheaper of an option. Free, plus the cable build which costs about $3 from radio shack if you have an old computer cable laying around. Besides, you get a lot more data from winALDL than you do a scanner.

    Just an idea.
     
  10. fortcollinsram

    fortcollinsram 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    After my experience with my TBI 350, all I can say is go get a fuel pressure gauge and hook it up..My SBC had hard starts, would lope like made when cold and would run like poo on a rellay hot day...Turn out my pump was only putting out 9psi at idle..when i put my 454 in, the 9psi was just enough to get it to run...If you go to Napa, look in the Echlin book, and under "Fuel Injection Cleaning Adapters" there are some inline adapter that you just go between the inlet line and the TB. and they have an 1/8" NPT port off to the side...Then hook up a gauge with the motor running...you want at least 10psi at idle...My 454 is at 13psi at idle...

    Chris
     
  11. Greenie

    Greenie Registered Member

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    I did not see the fuel injectors on the list. I thought 88 is injected. I had a rough start/cold start, like the choke was stuck. The injectors were wasted. When it is running look at the spray pattern, it should be even and and fine mist.
     
  12. bckinblk

    bckinblk 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    Ok .After I installed new vac hoses and checked everything over a second time I noticed that the temp sensor wire was chaffed .So I put a new wire on it and the truck never ran so good.. I can't believe that this little wire caused all this mess.I had to adjust the idle a bit but now the truck runs new again .I am glad I did'nt spend $150 for a scanner .But thanks to all who helped me out on this post . I hope that this post will help someone out in the future../forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/cool.gif /forums/images/graemlins/thumb.gif
     
  13. sled_dog

    sled_dog 1 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    one little wire causing a world of trouble, welcome to fuel injection /forums/images/graemlins/smile.gif. I couldn't figure out why last night and this morning my TBI chevy started real hard. Went up the street and stomped on it, oh boy almost out of gas /forums/images/graemlins/tongue.gif. Got the station and filled her the 32 gallon tank took 31.8 gallons
     
  14. bckinblk

    bckinblk 1/2 ton status

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    Re: ??TRUCK STILL RUNNING ROUGH..I\'M GOING CRAZY..

    I Guess it was grounding out for sometime .I actually forgot what a good running k-5 felt like .I contribute alot of the overall tightness and acuracy to the ORD steering brace Definetly worth $109 .It's drives like a new truck again .Now that the motor runs right (damn wire).I also put in a poly t-case mount and it eliminated alot of freeway vibes .I am very happy now (time for a victory six pac) Anyhow thanks dudes for helping me out with this .This site just all out kicks ass .Plenty of valuable info and cool people to boot...... /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif
     

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