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Chaplain Kent · 12-05-2004, 09:48 AM

My continuing struggle with the cruise control lead to an entire new system being installed. Now here is the problem which has eveyone baffled. The throttle, ie gas pedal will suddenly "pop" out of the cruise mode. Nothing will reset it it BUT if you hold down the throttle (gas pedal) at precisely the same spot it will rest itself. The gas pedal is very hard to push down and has a lot of tension on it could this be the problem? Has anyone else experienced such a problem? My mechanic has replaced all parts and checked all connections with no success. He has not looked at the throttle yet.
Cruise is essential to opearating this MH due to a physical disability so I am not seeking luxury here.

overlander63 · 12-05-2004, 11:58 AM

Most cruise control modules use a vacuum bellows to hold throttle pressure. If the force needed to push and hold the throttle down is more than the vacuum bellows is able to produce, it will either gradually slow down until the cruise control resets, and the throttle will go to idle, or if the vehicle is going up a little rise in the road, like an overpass, it will do the same.

I have driven Isuzu trucks with this engine, and the gas pedal has always been easy to push down. I would first check for something binding the linkage, like an air filter pinching the cable, or something riding on the mechanical part of the linkage. Something else I have seen once or twice, is the detent cable for the transmission binding, and causing the throttle to be very stiff.
Terry

74Argosy24MH · 12-05-2004, 04:27 PM

Even if it is an electronic cruise it won't work right if the accelerator is hard to push. Something is twisted, corroded, crimped, the cable is shot, or some one had a novel solution for a lead foot.

John

Chaplain Kent · 12-09-2004, 08:47 AM

I am always grateful for the replies and help I get from these forums. My expertise is not mechinical but with now my second vintage Airstream I am learning.
I checked the linkage, oiled and greased everything I could get my hands on. The cable is fine, no kinks, and operates smoothly. When I disconnect the cable from the throttle the mechinism is still very hard to operate by hand on the engine. There are two large springs applying pressure that allows the cable and thus the pedal to return to an upright position. Disconnecting the throttle I can not move these springs by hand. Granted i may not be the strongest but do they need to be so tight?
I will take the MO for a drive today and test if I have loosened it enough with the oiling.
Thanks again.
Chaplain Kent

bake315 · 12-09-2004, 10:09 AM

I'm no mechanic, but I know enough to know that the throttle linkage up by the carburetor should be relatively easy to move with your hand. I wonder if someone has installed an incorrect spring at the carburetor - one that is stiff enough to make it harder to press down the accelerator - and stiff enough to overcome the vacuum systems ability to hold the throttle at a set point.

Of course, I don't think the Isuzu diesel has a carburetor - but injectors, so I'll make that one change.

thenewkid64 · 12-09-2004, 01:33 PM

Dave,

I think you may have hit on the issue. The throttle in my Mh's was no harder to depress than any other vehicle I have owned. If the springs are as Kent describes, I bet they are the wrong ones. That or someone was attempting to over come a lead foot style of driving.

Kent,

I would remove the springs and replace them with a more typical set of throttle springs. If you have a local NAPA they should be able to tell you what ones are correct for the application. My guess is that they would be the same as a 454 powered unit of the same vintage since the cable and linkages would need to be compatible.

bake315 · 12-09-2004, 04:55 PM

Quote:

Originally Posted by thenewkid64

That or someone was attempting to over come a lead foot style of driving.

Or possibly even the PO thought the accelerator was TOO touchy - barely touch the thing and it takes off, so they put larger springs on to stop that - and got a little carried away?

Either way, it makes sense!

overlander63 · 12-09-2004, 08:53 PM

Why not simply remove ONE of the springs, and see how it works? Why buy something you may not need?
Terry

zamboni · 12-10-2004, 03:23 PM

Our MH does "pop" out of cruise mode if I hit an extra ordinarily large bridge seam or bump. I thought it was just attributed to a brief jolt to the electrical connections. Not a big deal to reset the button though.

Our diaphram had dry-rot when I bought the MH, went to U-wrench-It and found a capatible replacement after no local part store could locate the exact match for me.

Also looking for a vacume solenoid for the throttle position actuator. It keeps the throttle set at a higher RPM until the engine temp rises enough to back it off. No parts store I have searched at has been able ot find one.

Chaplain Kent · 12-27-2004, 02:27 PM

I have thoroughly cleaned the throttle and cable plus removed one of the springs. The gas pedal does work easier now and the best news is nthe speed control appears to be working. I have a long trip planned for this week and that will be the test but so far so good. Thanks to all who gave thier ideas and input.
Kent