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Thread: Start over,

  1. #141
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    Quote Originally Posted by Tinbender59 View Post
    Well my sorry ass installed a set of TPI injectors, i believe that they are rated at 45 psi, if my sorry ass remembers corectly, but please keep the insults comming because, well --- I'm stupid.
    Oh, if the injectors are rated at 45psi then don't run them at 58psi or they'll explode.

    Seriously.... the injector's 'rating' is actually a fuel flow rating and they specify the fuel pressure used to obtain that rated flow. You can run a fuel pressure higher than what they use for rating the injector... it just means that the flow rate will be higher than the rated flow rate.


    Quote Originally Posted by Tinbender59 View Post
    However today I got the oscope out ( and i actually figured out how to turn it on) and found the problem. As somone had sugested earler as well it was a bad ECU. I'm not ignoring your suggestions and advice, I have to prove to myself that the money is spent wisely and not wasted.
    Testing the spark wire resistances doesn't cost a whole lot of money... but it doesn't matter now, you seem to have found the problem.

  2. #142
    Lifetime Member Tinbender59's Avatar
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    Ah ya had call me out, lol true story on the wire's but I did honestly forget to do it. My apologies sir

  3. #143
    Joe (Moderator) joecar's Avatar
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    I love oscilloscopes

  4. #144
    Lifetime Member Tinbender59's Avatar
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    Well I guess this is where I get to eat some crow. The ECU did not fix it!! So here's where I am at; new plugs, new wires, new coil, new cam sensor, new crank sensor, complete set of "different" injectors, swapped ECU. Performed a decarboning process (water and oil mixture) compression test, 150# on #5 & #7 didnot test compression any further.

    I am now searching for the needle in the haystack.

    How does the ECU determine a misfire?? Does it read the knock sensor and the firing sequence? If so it could be a flywheel bolt hitting,? ( I did not install the transmission, so I cant garantee anything). Could it be a restriction in the intake? Something on the top of the piston?

    These 8100 are not cheap to work on so I really don't want to go shotgun on it

  5. #145
    Joe (Moderator) joecar's Avatar
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    ECM determines misfire by watching if the crank continues to decelerate after an ignition event...
    crank should momentarily accelerate, if it does not then that's counted as a misfire...
    knock sensor is not involved in misfire detection.

    What do misfiring cylinders show for compression and leakdown vs the good cylinders...?
    Does CKP reluctor look ok...?
    How good is spark on the misfiring cylinders...?
    How good is spray on the misfiring cylinders...?
    Are any valves not seating properly...?
    Are any valve springs broken or weakened...?
    Does cam have any lobes with flat spots...?
    Have any lifters failed...?
    Any visual signs of combustion chamber damage (from fragments of ringland or valve seat)(implies removing heads, or using borescope to view inside CC's)...?

  6. #146
    Lifetime Member Tinbender59's Avatar
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    Thats a lot to check in sub freezing weather, lol but all good advice, but if I have to pull it out? it'll be spring and probably will go a different route then. I'm not going to keep throwing a bunch more money at this thing.

  7. #147
    Lifetime Member Tinbender59's Avatar
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    Listened to the. Motor with a stethoscope at 2200 the valve train is just hammering away. Guess I will be pulling the covers next week.

  8. #148
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    Quote Originally Posted by Tinbender59 View Post
    Well I guess this is where I get to eat some crow. The ECU did not fix it!! So here's where I am at; new plugs, new wires, new coil, new cam sensor, new crank sensor, complete set of "different" injectors, swapped ECU.
    For someone who prides himself on spending money wisely.... that sure is an impressive list of wasted money.

    Quote Originally Posted by Tinbender59 View Post
    I am now searching for the needle in the haystack.
    The 8.1 can be a finicky engine... as you're now finding out. Sometimes it can be something simple that the engine just doesn't like. Joecar has given you list of things to look at, so that should keep you busy for a while.

  9. #149
    Lifetime Member Tinbender59's Avatar
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    That it will!!

  10. #150
    Lifetime Member Tinbender59's Avatar
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    That it will!!

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