High Idle circuit PT's/FC's

[Ralph L. Fullenwider]

Morning Bill:

Happy Thanksgiving to you and yours.

Your problem in neutral using the cruise control for high idle could be an
either/or situation. Though I doubt it is a low voltage problem because the
low voltage would drop the cruise out, on the road.

The air comes from the Coach air supply (wet) tank to the air regulator
located to the right of the Bendix control behind that cover you mentioned.
That pressure reducer, takes the PSI from 120 psi to 80 to 90 psi, then
goes through the valve located on the front of the Bendix control and from
there to the transducer. There is more in that line for the FC's that the
PT's don't use.

I don't have my Bendix cruise control manual here at the house so I can't
fully try to help but will get back with you on this when I do.

Safe travels,

Ralph and Charolette Fullenwider
Ralph's RV Solutions, Duncan, Oklahoma
http://home.swbell.net/rlf47/index.htm

At 02:46 PM 11/24/2005 +0000, you wrote:

>Hi Ralph,
>
>
>The cruise control on our FC works as you have stated. It is
>steady and pretty accurate at highway speeds. All the controlls
>operate as designed.
>
>But in the neutral idle mode, it is intermittent, It sometimes
>operates properly, other times it will not control the idle speed
>and sometimes the high idle will bump the trottle to full open.
>Do you have an idea of what could be causing this? Is it possible
>that there is a lazy relay or solenoid?? What is the minimum air
>pressure required?? Could it be low voltage or a bad ground? I have
>pulled the cover off and all the parts look like new and quite
>complicated. I decided that I would live with the minor inconvience.
>
>Happy Thanksgiving,
>
>Bill 88 FC
>
>--- In WanderlodgeForum@yahoogroups.com, "Ralph L. Fullenwider"
> wrote:
> >
> > Good morning everyone:
> >
> > High idle circuit on the PT's;
> >
> > Power comes from the ignition on cb to the high idle switch on the
>dash
> > (some PT's have a manual valve rather than an Allen Air electric
>valve)
> > from the switch on the dash to the low pressure (60 psi) switch to
>the
> > neutral safety switch. From the neutral safety switch to the Allen
>Air
> > valve (high idle which is normally closed)
> >
> > When the Allen Air valve opens, it sends air to the transducer
>located on
> > the left side of the of the engine on the throttle control unit.
>The high
> > idle circuit interacts with the throttle control valve, making it
>more or
> > less inactive because of the amount of air being supplied to the
>throttle
> > transducer. How that works will be explained when I get the write
>up done
> > on the throttle control circuit. And I find that system
>interesting.
> >
> > High idle on the FC's;
> >
> > High idle on the FC's is controlled by using the cruise control in
>neutral.
> > Turn the power to the on position. then hit the set switch and
>each time
> > you do that, the RPM's raise a calculated amount. To lower the
>amount of
> > RPM's you hit the decel side of the set switch and the RPM's will
>drop the
> > same calculated amount. To cancel the high idle turn off the
>cruise control
> > power.
> >
> > Safe travels,
> >
> > Ralph and Charolette Fullenwider
> > Ralph's RV Solutions, Duncan, Oklahoma
> > http://home.swbell.net/rlf47/index.htm
> >
>
>