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  1. #1

    Rebuild Roadblock..02 GTX 4tec

    Hey guys...working on this 02 GTX 4tec that had a broken crankshaft. Dunno how it broke, but it certainly did. Regardless, I got a replacement and while I was at it did new bearings, rings, thrust bearings, gaskets, and stretch bolts. Threw the sob all back together and put it in the ski....went to crank it over for the first time and it backfired harder than I've ever heard anything backfire. May have been loud cause my head was in the cock suckin thing but none-the less. Now I know the first thing one would assume is timing, but I feel very confident I have the timing done correctly except for on this particular model it does not have the 3 balance dots for the sensing wheel, but I did put marks on it prior to tear down so I am certain it is installed correctly. Plus I used the crank and camshaft locking tools making it virtually idiot proof....well

    So lastly I do own a scan sea and it is reading a fault code of "short to ground"...I suppose a short could in-fact make it backfire but I am second guessing myself all over the place at this point. Some help if you could please.


  2. #2
    Kiwi spanner handler
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    did you use the right year crank as they differ in the position of the dowel pin that locates the flywheel/trigger wheel.

  3. #3
    shrabber's Avatar
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    First thing I would do its the easiest way to find a goof up is run a compression test do not try starting it if your timming is off which I suspect it is and it does fire over it can lead to more than a backfire. It can be something simple but running a compression test will rule out the obvious. Other steps lock your crank and check your cam positioning up top. Me personally I'm and old school guy I like to stick a extension in #3 cylinder and creep it up to tdc and then I will see where my crank and cam is in relation to it. All this stuff will be mute is compression is off.
    Last edited by shrabber; 10-26-2012 at 10:44 AM.

  4. #4
    Quote Originally Posted by jasonze View Post
    did you use the right year crank as they differ in the position of the dowel pin that locates the flywheel/trigger wheel.
    +1. Sounds like you put the wrong crankshaft in. If you put a 2006+ crank in an early ski, it will backfire like that and will not start.

  5. #5
    shrabber's Avatar
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    Throw a compression tester if its the wrong crank your compression will show that as well. Then pull the engine and repeat steps 1-100

  6. #6

    Rebuild Roadblock..02 GTX 4tec

    Compression is 150 across the board. I'm pretty sure the crank is right of course something has to be wrong and it sounds like a good candidate. its possible too that the local dealership told me the wrong superseded part number. I'd have to look up again what this one we bought is but I know it was a "420" part number. Maybe that's what I should do is look it up off my invoice and post it to see what you all think thanks for the feedback.

  7. #7
    Here was my process for timing, rotor, sensing wheel, and flywheel installation: I locked the crankshaft using the tool, which puts it at TDC for #3 NOT #1 as per the book
    Click image for larger version. 

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    The flywheel and sensing wheel are a no brainer since it has the locating pin, but where I am second guessing myself is at this step. My rotor did not have the balancing holes therefor there was nothing to align, however, I did make a small mark with a marker during disassembly on the rotor and the flywheel and I'm pretty sure I have it back to how it was, but if someone has info about the rotor when there is no balancing holes I am all ears. Note that the rotor does not have the hole for the locating pin on the crankshaft, only the flywheel and sensing wheel do.
    Click image for larger version. 

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    Next I installed the timing chain gear with the crankshaft and camshaft locking tool still installed. I aligned the two "1503" marks on the gear with the top of the head as such:
    Click image for larger version. 

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    With that installed I installed the rockers and torqued to spec.

    I'm still working on getting some part numbers posted to see if anyone can verify that the correct crankshaft was used. Again I appreciate everyones replies.

  8. #8
    shrabber's Avatar
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    now its time to recheck all your connections and grounds. Ground is very important for proper sensor operation. That is correct Backwards seadoos Lol

  9. #9
    Quote Originally Posted by shrabber View Post
    now its time to recheck all your connections and grounds. Ground is very important for proper sensor operation. That is correct Backwards seadoos Lol
    That's what I was hoping for was a wiring issue, I really didn't want to pull that engine back out for the 3rd time. With that said you think that it must be the right crankshaft if compression is good? Could it not have good compression and still be the wrong crankshaft? I do own a Scan Sea and have the ability to pull codes and the codes do say "short to ground" but I, like you, am old school and have found that generally on rebuilds there is a mechanical problem.

    My worry is still that rotor position. In the manual it states that if you were to install the rotor with the 3 balancing holes exposed between the big gap on the sensing wheel it would cause "a non starting situation". Yet it doesn't say anything about models that do not have the balancing holes like mine is. My gut tells me the timing is off. I've had cam position sensors go out in many different machines and they will still run....just not well. That's why I'm not convinced it's a wiring issue.

  10. #10
    Moderator beerdart's Avatar
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    The crank deference is the crank trigger and trigger wheel. 02-05 it just passed 12:00. 06+ is just passed 6:00.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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