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Author Topic: Someone please explain  (Read 905 times)
chazwood
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« on: December 20, 2012, 08:10:51 AM »

Been adjusting my throttle position sensor because the po rigged it after the mounting bracket broke.
In doing so, I took off the linkage to the PT fuel pump and started laughing. The fuel pump shaft has a travel of about 45* degrees from full open to full closed. The linkage, however, has a spring loaded pivot that will move 3 times that. This is what was funny to me. When you mash the gas pedal an inch, the shaft on the fuel pump goes full travel. You are now floored. But because the spring loaded pivot on the linkage will allow a much longer travel you can push the pedal down another two inches but it won't move anything at the fuel pump!! You won't get any more fuel! The pump is already wide open. When I told my wife this she said "you mean to tell me all this time I've been getting cramps in my leg mashing the pedal to the floor my mashing hasn't made us go any faster!!!"Huh
Why the heck would cummins sell a throttle linkage with a pivot for extra travel that was misleading?
I guess having a little more travel in the pedal might take some stress off the fuel pump shaft in the case of a gorilla driver with a 900lbs foot, but why not say "look people, the last 2/3 of your pedal travel is strictly for show. Mash it if you want (if it makes you feel better) but the fuel pump shaft only moves so far.

And to think I actually felt guilty about flooring this thing and wasting fuel,when in reality, I had the silly thing floored in the first inch of pedal travel!
No wonder my fuel consumption never changed no matter what I did.

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1992 MCI 102c3
Cummins l10 / Allison auto
Thekempters.com
Jeremy
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« Reply #1 on: December 20, 2012, 08:53:03 AM »

Maybe the Cummins engineer who designed it was a fan of Spinal Tap:

Spinal Tap - 11
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chazwood
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« Reply #2 on: December 20, 2012, 09:22:41 AM »

Maybe the Cummins engineer who designed it was a fan of Spinal Tap:

Spinal Tap - 11


ROTFL!!
Yes! That explains it!!!!!
« Last Edit: December 20, 2012, 09:25:29 AM by chazwood » Logged

1992 MCI 102c3
Cummins l10 / Allison auto
Thekempters.com
wg4t50
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« Reply #3 on: December 20, 2012, 12:26:57 PM »

Maybe think of what happens when you have no spring linkage and you MASH the pedal to the floor, just maybe you will break off the arm into the PT (Cummins) pump and your going no where.
Just a thought as my Cummins mechanical also has the breakaway likeage to prevent damage for the same reason.
Just Saying
Dave M
« Last Edit: December 20, 2012, 04:37:22 PM by wg4t50 » Logged

MCI7 20+ Yrs
Foretravel w/ISM500
chazwood
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« Reply #4 on: December 20, 2012, 07:22:24 PM »

Maybe think of what happens when you have no spring linkage and you MASH the pedal to the floor, just maybe you will break off the arm into the PT (Cummins) pump and your going no where.
Just a thought as my Cummins mechanical also has the breakaway likeage to prevent damage for the same reason.
Just Saying
Dave M

Hence the gorilla reference
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1992 MCI 102c3
Cummins l10 / Allison auto
Thekempters.com
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