c-15/3406E inj adjustment

Discussion in 'Trucks [ Eighteen Wheelers ]' started by crazzy448, Jun 17, 2009.

  1. crazzy448

    crazzy448 Light Load Member

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    May 3, 2009
    panhandle wva
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    This is for the mech out there. When you adjust the inj. Setting it higher that spec or lower give power. I have heard higher than the cat tool add more fuel. Also lower increases squize for more fuel pushed out. Making me really wondering
     
    Last edited: Jun 17, 2009
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  3. Jas

    Jas Medium Load Member

    I always set them to the lower step on the tool, seems to work well for me, no complaints yet and I've done hundreds. Others will probably disagree and in the end its probably more important that all cylinders are set the same.
    I have done a lot where the injectors were all on the top step and I set them to the lower step, didn't get any low power complaints afterwards, some say the power improves, others cant notice a difference.
    If someone does an injector on the side of the road on one of my customers trucks and sets the injector to the high step the truck oftens turns up with the driver complaining of the truck running rough or "it just doesn't sound right", all I need to do is reset the injector height on that cylinder and the engine is fine.

    Having said all that if you look at how the injector works in a C15 manual it shouldn't matter how the injector is set as long at its with the spec (between the steps)...but it does, funny huh.
     
  4. 05chopper

    05chopper Light Load Member

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    Dec 25, 2008
    USA
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    I did both settings then I went to dyno I couldn't tell or see any difference in horsepower.If you decide to set injectors lower go in small increments.
     
  5. Heavyd

    Heavyd Road Train Member

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    Feb 4, 2009
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    LOL. This is another myth. Some drivers do "believe" they have more power or get better mileage, but for the most part it is in their head. No disrespect intended! If there is a power or mileage difference it will be from the valve settings and or all the injectors being set the same. The height of the setting for the injector doesn't change the stroke of the plunger, just the position in the injector barrel. The metering of the injected fuel is all controlled by the solenoid. The only thing that would change by lowering the setting adjustment is the plunger would ride on an unworn section of the barrel. This would result is less fuel leaking up past between the plunger and barrel and therefore the normal amount of fuel is injected compaired to a lessor amount due to the leakage. But I still think this all too minor to notice.
     
  6. 9 Axle

    9 Axle Light Load Member

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    Feb 7, 2009
    Purdon, Texas
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    Each & every truck is built with an "assometer & a right footometer" unfortunatly none of them are calibreated the same! Therefore it's still up to the dyno to sort it all out!
     
  7. crazzy448

    crazzy448 Light Load Member

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    May 3, 2009
    panhandle wva
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    The place i work at was going to put a dyno in but nixed it at the last m oment with the the ideal of the wash also. 1 of are facilitys have one but i dont have the access to go use it over 1 hour away. i would love to play on one. Does any one know of a moble unit for big truck?
     
  8. 9 Axle

    9 Axle Light Load Member

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    Purdon, Texas
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    Jesus, a wash in place of a diagnostic tool????????? No wonder the entire North American Continent has fallen into a third world state. Just VERY glad I'm as old as I am !!!!!
     
  9. crazzy448

    crazzy448 Light Load Member

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    May 3, 2009
    panhandle wva
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    No they were putting in both and didnt do either
     
  10. Jas

    Jas Medium Load Member

    I agree in theory it should make no noticable difference and dyno results dont show anything either but I know for sure drivers can tell the difference, strange as it may seem its not one or two drivers that have noticed a difference but hundreds over the years.
    Now to get comlicated..... winding the adjuster down does increase the stroke but its all in the rocker arm not the injector. Think with me for a minute... the rocker ratio is the distance from the roller/cam contact point to the centre of the pivot point of the rocker shaft verse the distance between the centre pivot point of the rocker shaft to the centre of the contact point on the bottom of the adjuster. Now because the adjuster moves (when adjusted) in a straight line rather than in an arc around the pivot point of the rocker shaft by winding the adjuster down you are in fact slightly increasing the length between the pivot point and injector contact point, so you are very slightly increasing the rocker ratio therefore giving more injector stroke per degree of crankshaft revolution and as such more fuel which equals more power, how much power? Probably not much but mathmatically there is a very small gain.

    Sorry if this doesn't make much sense, just my thoughts out loud.:biggrin_25525:
     
  11. 9 Axle

    9 Axle Light Load Member

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    Feb 7, 2009
    Purdon, Texas
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    Jas, you are TOTALLY correct!!!!! Rocker arm, (cam follower) ratio & geometry is critical to the operation of an internal combustion engine!
     
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