5-June-17:
I got the VSS working off the 4L60e the only issue I had was the need to divide the signal by 64, the 4L60e uses 128,000 ppm and the Cruise Control needs 2000ppm. I bought a Digitech VSS divider but this is limited to a divide by 2 so I used 4 D type flip flops after the Digitech to divide the signal down. I now had CC that would engage from 40km/h to 110km/h, it would go more but in the interest of safety I kept my speed to the limit.
Next issue I had to solve was terrible surging when the CC was engaged. The CC was pulling so hard on the throttle that on a flat road the transmission would keep kicking back to 3rd gear, NOT a very pleasant ride. It seemed like the CC was pulling way too hard on the accelerator. To solve this problem I made a bell crank to halve the pull from the CC unit.
This is a proof of concept and it worked, the CC is now much smoother and does not kick down even on hills. So I will now fabricate a better bell crank.
The CC works, the only issue I have to resolve is the speed signal. The Jaguar VSS in my car (Diff mounted speed sensor) is 8000ppm (pulses per mile) so the CC works up to 97km/h. I have purchased a VSS interface unit to allow me to divide the VSS by 2. This should solve my problem.
I have ordered of eBay another Commodore cruise module from a VR Commodore. So I have removed the circuit diagram and will re-post when I have got the system working.
I have done my best to document the process, but being a technician I do tend to leave out details. Anyone wanting to copy this installation is welcome to do so and drop me a note if you have any questions.
As usual with V12 Jaguars my cruise control bellows had deteriorated, so I ditched it a couple of years ago with intention of installing electronic cruise control. I found most of these units are pretty expensive at around $600AUD. So I decided to retro fit a GM cruise control module from the Aussie Commodore, mine is from a 1994VR. This is an AC Delco module as used in the US Tahoe.
The GM module incorporates the Cruise Control Actuator and ECU in one unit simplifying installation. It's just a matter of cutting the Jaguar plug off and crimping a new plug on for the harness to the module.
Rather than installing it in the engine bay I decided to put it in the LH guard behind the front wheel. This necessitated a longer cable. If I was doing it again I would put it on the drivers side rather than the passengers.
To make it easier to remove the engine for my upcoming engine swap I fabricated a bracket that bolts under the throttle pedestal. This is a temporary arrangement, when I replace the engine I will fabricate a new capstan that will allow me to connect the CC directly to the pediatal.
The GM cable was too short to reach all the way to the bracket on the throttle pedal, so I bought a new longer cable from a pushbike shop. The aluminium sleeve I machined up on the lathe and cut the end off the original sheath.
I covered the join and most of the original sheath in heat shrink to prevent it from coming apart.
I removed the eyelet from the original cable, drilled out the end and swaged it to my new cable. Hopefully it will hold.
I thought I took photos of the throttle pedal installation but I obviously didn't as I can't find them. I cut the new cable a little too short which made getting back together a real PITA.
To use the GM cruise control I needed to modify the wiring of the master switch. The GM unit needs 12volts for the switches and the Jaguar uses switch to ground. There is a modified wiring diagram towards the end. The GM unit also gives me resume/accelerate and set/decelerate. The switches had the input wiring tied to a convenient 12v supply with a 470R resistor in series with the output for resume and set.
The wiring changes necessitated changing the connectors in the master switch. Use a small screw driver to remove the terminals.
The Green/Yellow wire is 12v, The Black wire is also now wired to 12v, Yellow/Orange is ON/OFF and Black/Slate is Resume. These wires need to be removed and change position in the plug.
Switch Wiring changes.
Green/Yellow pin 3 top left
Black pin 4 top right
Black/Slate pin 2 middle right
Yellow/Orange pin 1 middle left
Connectors added between Jaguar loom and harness to CC module in engine bay.
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