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BB06 Hopeful...I need TBI conversion help!

Discussion in 'Rocky Mountain Region' started by juanblzer, Sep 15, 2006.

  1. juanblzer

    juanblzer 1/2 ton status

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    I'm desperately trying to get my motor started but it just won't turn over. Here is what I have:
    85 GMC Jimmy
    1990 tbi and sensors
    affordable fuel injection harness (with egr,AIR, knock removed)(also removed from chip)
    new chip
    edelbrock performer intake
    454 tbi adapter plate

    I'm getting fuel
    I'm getting spark
    the timing is right (its been double checked)

    It's backfiring out of the tbi
    It's not turning over.

    I was really hoping for my blazer to make it to BB04 but I still have fab work to do and it's not happening until I get this motor running and debugged.

    I'm around Saturday after 2pm (driving school:doah: ) and all day Sunday.
    If you want to help a brother out give me a call
    480-391-1080

    Does anyone have a scanner for ALDL port?
     
    Last edited: Sep 15, 2006
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    what type of distrubtor are you using, a TBI one or the old style large cap?
     
  3. B_to_C

    B_to_C 1/2 ton status Author

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    Sorry to break it to you dude, but you're about two years too late for BB04 :haha:
     
  4. juanblzer

    juanblzer 1/2 ton status

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    Doh! I fixed it.
    TBI distributor not the old one
     
  5. FWP

    FWP CRS

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    Got the firing order right?

    When you say,"not turning over" What do you mean?
     
  6. juanblzer

    juanblzer 1/2 ton status

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    it cranks but won't start
     
  7. 1979jimmy350

    1979jimmy350 1/2 ton status

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    if you have the knock sensor removed and are using a TBI style distributor, how do you expect to get the most out of the swap? That cousl be causing you some trouble, with no knock sensor your timing is not going to advance correctly which is goning to cause timing issues
     
  8. 4xcrazy

    4xcrazy 3/4 ton status

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    i know you said you double checked the timing, but are you SURE it's not 180 out, that's what it sounds like to me:crazy: even though the piston is TDC, and timing marks line up, 50/50 chance there:o
     
  9. FWP

    FWP CRS

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    K. Now, was the motor you installed running before the swap? Was there any internal work done- ie, cam, timing chain etc.? From the sound of what you're describing (Fuel and spark, with backfire) but no run, the firing is incorrect, either in the valve timing or the spark getting to the cylinders (Distrubutor, wires, etc).
     
  10. bigblock72

    bigblock72 1/2 ton status Premium Member GMOTM Winner

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    You'd better quadruple check that distributor, sounds like it's 180 out. Remove number one spark plug and spin the motor until air is forced out of plug hole, remove dist. cap and check.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm going to +1 the check distributor position. You need fuel and spark, if it's backfiring it's got both, but at the wrong time. Simple as that.

    Beyond that, do a search for posts that contain the text "crank no run" started by me, and you'll find the troubleshooting post that has the chart to follow. But seriously, don't even waste your time with that until you make doubly sure the distributor is in right while at TDC #1!

    As an aside, I'm perplexed by people using "won't turn over" to indicate that an engine won't start. Isn't it "turning over" if the starter is rotating the engine? It's not *starting* if it cranks over but won't start, no?

    I wouldn't worry about the knock sensor. It won't come into play until the vehicle runs, and injection does not "advance" timing until it pings then back off for optimum performance. Max timing before it pings does not and has never meant that is where the engine makes the most power. The knock sensor test routine in some setups is that once the engine is running, increase spark to where it SHOULD knock, and if it doesn't see that knock, it throws a knock sensor (ESC I believe) code. If that routine has been "turned off" with a custom PROM, as I'm sure it has in this case, that routine will never happen, and it will have no bearing on how it runs. The system will simply rely on the timing maps in the PROM as it always does, but now oblivious to any detonation that actually *may* happen, such as with a batch of bad gas, during overheating, etc.
     
  12. mtnman

    mtnman Scrap metal fabricator Premium Member

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    I quadruple checked the timing personally, and it is right, I am certain. Even checked w/ timing light while cranking - fired at #1tdc. I've done this stuff a hundred times and I am baffled !!!! BTW I do not understand how you guys live in that hellish heat:screwy: and it was only in the upper 90's:angry1:
     

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