99 Burban needs help

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by ljjcsautomotive, Mar 6, 2007.

  1. ljjcsautomotive

    ljjcsautomotive New Member

    I've replaced my computer, entire ignition system (Ign controller,coil, wires, cap rotor, ect), crankshaft pos, cam pos, and a mess of other items to include the fuel pump and the fuel injection spider. Finally found the culprit!!! The distributor gear was chewed all to hell but the cams looks fine. Got the motor to finally fire but it stalls instantly. I'm burnt out and need some fresh ideas. Please help. maybe timing 180 off?
  2. TrailLeadr

    TrailLeadr New Member 1000 Posts 100 Posts

    Very possible, but I'm thinking it would sound like it wants to start, but never actually fire a cylinder if it were off 180. But it's worth looking into.

    I had a friend who used to call those kinds of things "Stupid Genius problems"
    You spend all the time looking for the biggest reasons why it doesn't work, and it turns out to be the simplest thing.

    You said the cam gear looks fine, did you pull the cam, or just look down the hole with a flashlight? The cam could be off a tooth if you pulled it.
  3. ljjcsautomotive

    ljjcsautomotive New Member

    Looked down hole and rotated the engine slowly. It runs for about 2 seconds then dies. It has to be something stupid I'm just to wiped out to think straight.
    1 person likes this.
  4. MrShorty

    MrShorty Moderator 1000 Posts 100 Posts

    Engine needs 4 things to start and run: Compression, Air, Spark (at the right time), and the correct amount of fuel.

    Compression: Because you are getting a sputter, you must have some compression. This is probably the last thing I would look at.

    Air: Rarely is air the problem. Air is so easily available and there's very little that prevents air from getting into the engine. Will it start if you crack the throttle open a little bit (might indicate a problem with the IAC valve).

    Spark at the right time: Are the spark plugs firing? If timing was 180 off, that would mean the spark plugs are firing at the top of the exhaust stroke rather than at the top of the compression stroke. I wouldn't expect even so much as a cough if the timing was that far off. The fact that the engine fires suggests to me that the timing is at least close.

    Fuel: Other than replacing a few things, I don't see any mention of fuel system diagnosis. What is the fuel pressure? Spec is 60 psi, is it staying at 60 psi after the engine "starts?"

    I've also found that it sometimes pays to ask the computer if it's seeing a problem. It doesn't always help, but, if you have access to a scanner/code reader, it only takes a few minutes to hook that up and see if the computer has any problems to report.

    Good luck.
  5. ljjcsautomotive

    ljjcsautomotive New Member

    Getting plenty of fuel 62 psi with upgraded fuel spider, regulator, pump, and filter. When I give it throttle it gurgles and dies. Computer not giving me any codes or other information. It start up after a long crank them dies in a couple of seconds. I'm still lost as to this problem. My factory service manuals don't give me much but to check the intake for leaks and check the emissions system.
  6. unplugged

    unplugged New Member 1000 Posts 100 Posts

    Vacuum leak is a possibility. Smother the carb by cupping your hands over the TBI and crank it. See it if revs or runs at all. Otherwise, what is your timing light telling you?
  7. ljjcsautomotive

    ljjcsautomotive New Member

    Finally got it. I had to hook it up to a GM computer. Had to reprogram the security system. Started right up and runs great. Only one thing, it starts almost the same time I turn the key. I think the timing still needs to be adjusted a little. Wont run right yet with my MSD 6A. misfires a little. Now I have to replace the EGR too. Stuck closed.
  8. WESWORLD

    WESWORLD New Member

    How did you reprogram your security system? My 99 is going has been doing this for months. I usually wait until it starts and pull the security fuse and it runs forever. Now it finally will not start. Need advice.
  9. Pakeboy2

    Pakeboy2 New Member

    Any update on how to reprogram the security system?
  10. 84fiero123

    84fiero123 New Member Platinum Contributor 1000 Posts 100 Posts

    duh, i have to remember to read all the posts.
    Last edited: May 16, 2007

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