cruise control for high idle

Vehicle: 1996 Dodge 2500 5.9 CTD

I have a factory cruise control and want to use it to set a high idle and hold it. I have looked into using the vacuum controlled cruise control actuator by having a bypass switch that applies power to the cruise circuit.

My current issue with doing this modification is a semi precise way of setting the desired engine speed. I am looking for help in the way of a diagram for a fixed pulse circuit that will apply with each switch bump that is around 200-400 milliseconds (i think). In looking at the factory wiring diagrams the brake switch will still work as a safety to the system and disengage upon being applied.

Thank you for your help and any suggestions.

Could you do an idle air solenoid with a flow valve on it? If you plumb it in behind the throttle body it should, in theory, allow you to change your idle by applying power to the solenoid.

To use a cruise control solenoid you are going to need an accurate way to measure engine RPM and then modulate the throttle accordingly. I doubt that a simple open loop pulse setup will provide adequate results considering all the variables that go in to determining how fast a motor will spin.

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Kevin Pierson

Have you checked to see if there was a factory PTO option available for this year truck?

I know the newer GMs and maybe the FORDs have an ECU pin you ground, and you can select a different idle speed with the cruise control buttons. Usually this pin is wired with a relay via the parking brake as a safety implementation. (parking brake engaged for PTO operation)

Might already be some aftermarket solutions available too.

The main issue is that my truck is a mechanically injection pump without any electrical controls. The ecu is only present for the gauges and cruise control which has a hard cable running to the throttle input on the injection pump.

Also because it is a diesel and does not have a throttle plate I cannot use a IAC to increase idle. they would be a simple mod on a newer gas vehicle that has engine management.

I am really just wanting a fixed pulse momentary switch to bypass the factory cruise control and use the vacuum actuated control to raise the idle until the brake is hit. I am getting tired of wedging the throttle with a tow shackle.

And yes I have thought about a cable hand throttle, but I want to use what is already in the truck. (and it would just be cool to have a high idle switch)