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HELP , I need help ASAP

Discussion in 'GM Powertrain' started by Bomber, Feb 21, 2010.

  1. Bomber

    Bomber New Member

    Hi i am new here to this website but it seems great , i have a problem with my 2000 silverado v6 that i cannot figure out , and its making me go insane , the problem started about 4 months ago , the truck sometimes does not want to start in the morning when its cold outside and if it does start it misses in 2nd gear till it warms up a little , when it doesnt want to start i pull the spark plugs and they are fouled really bad to the point that it drips some gas out of the plugs , well i did some testing on the fuel pressure and went ahead and changed the regulator , the truck didnt start till one day it was in the 50 deg outside and it fired up right away and drove really nice like new for awhile till my SES light came on and i checked the code it said that the truck is running lean in both banks 1 and 2 and that was this past monday the 15th well i got out this morning to start it and its in the 30 deg weather and the truck didnt start, i pulled the spark plugs and they are fouled again! and i talked to 2 good mechanics and they dont know what it could be , i was wondering if anyone could help me out here , because this is my daily driver and work truck so i have to have it , any help would be appreciated
  2. somonenew1994

    somonenew1994 Member

    a stabb in the dark i have seen it once on a car with a bad egr usally it shoots codes but this one didnt just a try for it
  3. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    The plugs are fouling, which suggests that the engine is running rich. Other symptoms that would verify that it is running rich? Plugs fouling uniformly, or more on one bank than the other?

    The PCM is seeing a lean signal from the O2 sensors (there are several possible codes, it might be useful if we had the actual code number). Interesting contradiction if it does seem to actually be running rich.

    One wouldn't necessarily expect the O2 sensors on both banks to fail at the same time, but it can't be ruled out.

    1st thing I might do would be to put a fuel pressure gauge on it and see what the fuel pressure is. I'd probably also put a scanner on it to see what the O2 sensor signals are doing?
  4. Bomber

    Bomber New Member

    ok the truck is fixed i finally sat down and thought about it, and yes it happend before with the egr and been replaced and the truck ran fine, now the plugs were on both sides and the reason it is fouling out was that its cold outside and i didnt think that it needs more fuel to start, but one i remembered that i went ahead and checked the spark again and got up close and the spark was kinda orange, so i knew it was spark, i took the cap and rotor which i bought and installed a year ago,off and it was f'ed up bad because even tho i bought a year ago i also drove 30k miles for work and it was an autozone cheapo , so i replace cap and rotor ,wires and new plugs and she fired right away, the lean condition was the throttle body gasket, but thank you guys for the help!
  5. Bomber

    Bomber New Member

    ok now i have a problem with running lean on both banks, i tried using carb cleaner on the intake gasket since i changed it not to long ago , but nothing happened , the problem goes away on its own for a day and comes back sometimes as i am driving it goes away and an hour later comes back , and its driving me crazy, i checked the fuel pressure and its at 59psi , we got the truck on a lap top and it said that its adding about 20% more fuel just to get it to run right, i was thinking if i put a vacuum gauge would it tell me if there is an intake leak? any help would be appreciated
  6. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Are the plugs still fouled with gasoline?

    Do you get any code saying misfire or anything like that??

    I wonder- like others suggested- if your O2 sensors are bad-maybe killed by the raw gas that must have been baked on them when it was running so rich that you had gasoline fouled plugs?

    Tough one
  7. Bomber

    Bomber New Member

    no codes ,well just the ones that tell you that the truck is running lean which is p0174 and 171, no more fouled plugs , i was thinking of the o2 sensors but its something that is expensive to replace just to check, is there a way to check'em?
  8. Bomber

    Bomber New Member

    i had to bring this up because the truck is still doing it , it starts up fine and everything , it does hesitate after your start it and drive off right away, warm or cold it doesn't matter, i checked for vacuum leaks but nothing i sprayed with some carb cleaner and i even put a vacuum gauge on it and nothing shows up, as i asked before is there a way to check the O2 sensor because they are expensive to replace just to check, I really need help on this.
    Thank you!
  9. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    There are a few different ways to try to test O2 sensors:

    1) You can bench test with a propane torch. Hook up a voltmeter to the signal wires, put a torch to the sensor. The sensor should respond to the O2 poor environment in the flame with an increase in voltage. Out of the flame should be near 0 V

    2) Do you have access to a scanner that will let you monitor O2 sensor signal? What is the O2 signal doing?
  10. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Another thing that will cause your Lean condition is a bad IAC that isnt closing and opening properly.. Pulling it and cleaning it might not be to bad of an Idea..

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