[Shotimes] towing and fuel economy

[Paul Nimz]

Because of the more open throttle plate caused by your foot pushing the gas
peddle down further which reduces intake vacuum which causes the O2 sensors to
see the more O2 which causes the PCM to fire the FIs for a longer duration per
cycle which causes your wallet to empty faster.

TSB 99-26-9 explains it all if you are interested.  Math formula included.

Paul


On 5/28/2005 10:33:41 AM, van Oss (vanoss@centurytel.net) wrote:
> You and Porter have explained the physics.  I grasp the physics.  I think
> my
> question is more specifically about engine mechanics.  Let me break it
> down.
>
> -- Cruising at 40 MPH in 3rd gear, without trailer, the tach reads 2500
> RPM.
> Same speed and gear with trailer, the RPM should be the same, right?
> Because in the same gear the whole drivetrain is turning at the same rates,
>
> right?
>
> -- I grasp that with the trailer the engine is "working harder" and using
> more fuel.  With trailer, it takes more force to push the piston down.
> The
> injectors squirt longer, yes.  The computer, aiming for stoich, keeps
> the AF
> ratio as constant as possible,
> doesn't it?  So here is the main thing I
> don't grasp:  If the RPM is the
> same, then valves are opening and closing at
> the same rates.  How does more air pass through if the valvetrain is at
> the
> same RPM?
>
> Maybe
> I'm the slowest guy on the list.  Sorry.
>
> VO
>
>
> ----- Original Message -----
> It really boils down to simple physics.  It takes X amount of energy to
move
> a mass Y distance.  If you double the mass and all else being equal, it wil