Fast Idle-Fuel assumption ?

[hammer]

After I got the truck I installed the fast idle according to the forum instr. & it still works perfectly except when I use it the truck sucks fuel like crazy on any of the three RPM settings I use. I realize it is coupled to the PTO system but cannot see why it should take more fuel then when you just prop the throttle with a stick & bypass the fast Idle.Are the gears in the Allis for the PTO causing this consumption or what makes it use more fuel when using the fast Idle system?Kinda curious to the answer to this one.Dont beleive anyone has yet to ask this on the forum.Sure would like to find out why.Appreciate a sure answer from someone out there that has the knowledge for this.Truck has 26,000 on it now & is averaging 17.8 m.p.g. Hammer smile.gif smile.gif

[Kennedy]

Not sure how you are figuring fuel consumption, but I really doubt it has any affect.

Now, keep in mind that curb idle is "balanced" by the PCM, but anything above that, whether it be APP generated or ECM generated, and the balancing shuts off. This COULD be a factor, but unless one were to check idle fuel consumption in gallons per hour at precisely the same RPM for propped pedal and PTO setting, it would really be tough to determine any differences.

I really do not see how it could be any different.

[hammer]

Hi John Kennedy,I realize you are really knowlegible with these trucks & appreciate the feedback.I can run an average of two weeks betwen fuel fillups.But if I try & use the fast Idle too much it cuts my mileage down because it causes me to fill up within a week & a half.The reason Im using the fast Idle is were having 90 degree weather here & Im running the engine when Im parked somewere to do something for a short while.(More comfortable in the truck LOL) The fast Idle seems to keep the motor cooler at a higher RPM.I drove big rigs for 22 yrs. & when its hot or cold we ussually run the engines a little more then Idle speed.I guess its an old habit I cant break.Also brought the engine down off the high side of pulling.Kinda calms it down after a 9 hr. run.I can also see it in the fuel guage going down faster then if I just let it idle or even use a stick on the peddle. Thanks for the comeback,Very much appreciated.Hammer smile.gif smile.gif