Hello,

I have a 2003, F53 Chassis (Motorhome ) with a V-10.
I was wondering if I could make an adjustment to the cruise control cable or linkage to make it a little less sensitive.

If I'm on Cruise and we start to climb the slightest incline the cruise seems to try and keep the speed from dropping at all, it downshifts the auto transmission and the engine jumps about 2000 RPM, then it overshoots the MPH, upshifts, losses momentum, can't keep up,then does it again and again.
I realize the motorhome weighs a lot, I don't mind losing speed on up hill grade, so I'd like to adjust the max. throttle opening or rate of change for the cruise control actuator, so it doesn't do this so often.
It does this when approaching a freeway overpass, if I'm going over 55MPH.
This is my 1st Ford in a very long time.
Does this have a mechanical cable or linkage, or is it "fly by wire"?

Thanks,
Mike

 

There is no adjustments that can be made.
Your asking a lot from cruise control in a high weight vehicle when not on reasonably level roads.
How it works:
When you set the speed , it has a small range tolerance to stay within.
If there were no speed range limits it would shift even more and be very annoying by hunting on every small load change.
What happens when the controller opens the throttle by cable, the TPS sensor/throttle angle detection along with the road speed dictates what the PCM does with transmission shifting and is the same action as if you gave the motor more throttle by foot with the cruise control off.
Basically why the down shift occurs is the motor cannot make enough torque 'in overdrive at low engine rpm' to increase the vehicle speed keeping it within the speed limits 'before' the cruise controller advances the throttle angle to the point it tells the PCM to downshift.
The 1000 rpm spread is normal.
The cruise control is totally independent from the engine computer.
The only link is the mechanical cable movement it does the throttle position.
There is no gear in between to make the engine speed any less.
If it was a modern 6 speed transmission then yes it would work a bit nicer in this respect..
You can't do anything to change it.
.
The reason for the big jump in engine rpm is as follows in example.
If the rear gear ratio were 3.55 the OD ratio is .77.
That makes the final drive ratio (in OD) 3.55 x .77 = 2.73.
The down shift causes a change in total gear from 2.73 to 3.55 a big change that causes the engine to respond with a large rpm change.
This happens with either cruise control or your foot assuming the conditions on the road are the same if road speed is trying to be maintained to a certain speed.
Cannot be avoided.
Good luck.

 

Forget relying on the cruise unless you're on relatively flat terrain.

It cannot substitute for your brain analyzing what's coming up and making corrections as and slightly before they are are needed.

The speed control only relies on the vehicle speed sensor as an input. Once set, it attempts to maintain that speed by controlling the throttle via a drive cable. Vehicle slows down, cruise adds throttle to try to speed up. Vehicle slows down, throttle is backed off to allow speed to slow. That's it. Not anticipation of hills or anything else, that's what you're for.