I am looking for a mechanic to install a (rebranded) Rostra Universal Electronic Cruise Control.
The year in this context is important; it is the first model year with the electronic speedometer. It however has a mechanical throttle, not throttle by wire.
Converse to many other cars, the throttle pedal lacks a return spring; only the throttle body does, so the cruise control wire would be attached to the pedals. As such, given the speedometer's location, the entire unit can be installed in the dashboard without drilling holes in the firewall as far as I can tell.
Problem is, that no matter what custom shop I find, they immediately shy away from it the moment they hear it has a mechanical linkage. I have work, so I can't do this during the day when there's light out. That said, I do have a second car, so if it took more than a single day to install the cruise control that would be acceptable.
I would like to find a mechanic that would be willing to install cruise control. Can I please get some kind of lead on this?
SPONSORED LINKS Tuesday, January 7th, 2020 AT 2:00 PMCan you post a photo of the servo? I used to install a lot of Sears-branded units when I worked there in the 1980s. They had one model for less than a year that was a real piece of junk, but the less-expensive standard model was a dandy system and very reliable.
The first thing to look at is how the throttle cable is pulled. Most models do that by applying engine vacuum to the servo through some solenoid-controlled valves. You don't want to mount that inside the car. It is going to make repeated clicking or thumping sounds when the dump valve activates. It will buzz or vibrate to carefully adjust the throttle cable.
Also, there is no practical way to make the cable pull on the accelerator pedal. The location of the throttle return spring is irrelevant. The cruise control's servo is just doing the same thing the accelerator pedal cable does. If you can post a photo of the cable where it is attached to the throttle blade, that will help too. For those engines that used a quarter-round cable guide, they usually had two side-by-side. The second one was for the cruise control cable. The Sears unit, (was actually made by Dana Corp), came with a half dozen different connectors for the cable. One of those always fit every car I worked on. You must be careful to insure when you press the accelerator pedal while the cruise control is not engaged, that the cruise cable doesn't lift over and off the cable guide. That can result in very high engine speed.
There's also multiple ways the unit gets its speed signal. The Sears unit used a pair of magnets strapped to the front half shaft, or just one of them strapped to the rear-wheel-drive driveshaft. (Driveshafts spin three times faster than half shafts, so a single magnet generated enough pulses to keep the range of speeds it would engage at between about 32 to 85 mph.
They came out with a third model that connected to a vehicle speed sensor wire, but we didn't install a lot of them. For those, the unit will come with a booklet that listed the car models it will work on, where to fine the correct wire, and its color.
Some of the other brands of aftermarket cruise controls used a coil and metal core clipped around one of the spark plug wires. Those only held engine speed steady, not road speed.
That is fine with your manual transmission, but cars with automatic transmissions will lose speed going up hills, and gain speed going down. The Sears unit had a coil on a spark plug wire too, but it was only there to kick the system off if engine speed picked up too quickly, as in spinning on slippery roads or you bumped it into neutral.
Those other brands usually used real small-diameter wires. The Dana unit had fatter wires that were easier to work with. You'll need to attach two wires to the brake light switch. They gave us Scotch-Lok connectors for that, but those often caused intermittent problems. I always stripped the wires, then doubled them up to make them have a better connection. If either of those wires has an intermittent connection, the common complaint was the system would kick out when driving over bumps in the road. Mine never did that because I took the extra time with those connections.