Diesel Cruise Control


Diesel Cruise Control

Visitor # 30527 since 19.DEC.2001


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When I drove my '81 Caddy with its 1.6 NA diesel engine, I never felt the need for a cruise control. It was usually the case thet I just mashed the accelerator to the floor and whatever speed I went (usually well short of the speed limit). So after that vehicle was totaled and I picked up an '82 Caddy with 1.9 NA diesel engine, I found it had a bit more power and might benefit from a cruise control unit. After I tweaked the fuel pump a little, I needed a cruise control badly, as I'd be doing 80 before I noticed it.

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I picked up an Audiovox CCS-100 cruise control kit from JC Whitney for about $100. I mainly chose it for the small dash-mount control unit. I used to run a stalk-mounted control in a Rabbit once but it never fit well and was always breaking off.

A:Cruise control actuator B:Throttle cable connection C:Vacuum connection

I installed the control actuator in the vent area (A) and ran the control cable and vacuum line under the plastic tray cover. Attaching the throttle cable required drilling one hole in the existing bracket (B) and attaching the chain and eyelets to the throttle arm. Vacuum connection was to the factory pump, I cut the end off one of the unused fittings (C) and needed to run a drill bit down it to open up the seal inside. Then I ran the cable harness inside the firewall and hooked up the wires under the dash. The unit needs switched 12V and ground, then the red and purple wires get hooked to both sides of the brake light switch (one is constant 12V, the other is 12V when the brakes are on). Final connection was to my tachometer signal which connects to the blue wire from the unit.

In case you are wonding what all the other struff is on the top of the middle image, above, here's a rundown, (left to right):
- Auxiliary fuse block
- Optical tachometer signal generator
- Fog and driving light relays
- ISSPRO exhaust gas pyrometer signal conditioner
- Below that is my cold air pickup tube

The control actuator houses the units logic circuits and has DIP switches to control the unit's operation. For manual transmission vehicles w/o a Vehicle Speed Sensor (as I have) you must run off the tach signal and disble the VSS input with the switch setting. Also, you set the unit to 4000 pulses per mile (PPM) and I set the tach input to be from the ECU versus from the ignition coil (I think this tells the unit to expect a cleaner, high impedance signal, as you get from a computer. I set the module to medium sensitivity, although high might be better for a 1.6 NA engine.

Control module on dash

The control module was mounted on the dash. I placed it midway between the emergency flasher and my combination fog/driving light switch. A 1/2" hole was enough to fit the wires through and the module is held in place with double stick tape. It also need a dash light connection, I tapped into the cigarette lighter back light for this. Above is the completed installation. Also note the new center console, I have a Garmin StreetPilot III GPS in the lower bay, a pyrometer, voltmeter and analog clock in the middle bay. The upper bay will end up behind the ashtray unit I needed to remove to install the console. I installed a 12-position terminal strip for all my wiring connections.

Note, for the tachometer input, the factory alternator (i.e. W terminal) input will not work, the CC unit wants to see from 2000-8000 pulses per mile, which is in the range of a normal ignition system (2-4 pules per revolution). The W signal is about 12 times faster than this and the unit probably would not respond to that high an input. My opto-eletronic tachometer generator provides a nice clean 2 pulses per revolution and works perfect for this application

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[Created: 19.DEC.2001]

[Last updated: 26.March.2021]