Constant-Throttle cruise control

[whitetoy]

Well, I figured out how to do this relatively safely. Many suggestions usually involve an old choke-cable without a brake-pedal shutoff. Not good.

I do not have a little econo-box (sold my 91 Civic recently) but try to maximize my MPG's with whatever I drive. I currently have a stock 99 Toyota Tacoma 4WD with an automatic and 2.7 liter 4-cylinder motor. My mileage varies from 19 to 25 mpg depending on driving situations. Overall average is around 22. I occasionally get on the freeway, and would like to have a cruise control to minimize driver fatigue and improve MPG, but the truck did not come with one.

What I did, was to purchase a cruise-control servo and brake-light switch from a 99 Camry (Tacomas are rare in the local pick-n-pull yards). Being of the same year and manufacturer as my truck, made the servo compatible with my trucks throttle cable.
I mounted the servo under the hood where a factory servo would have been mounted, hooked up the stock accelerator cable to the servo, and the servo throttle cable to the throttle. I then replaced the stock brake-light switch (only 2 terminals) with the new one (4 terminals). The servo has 2 mechanisms : a magnetic clutch to 'grab' the throttle cable, and the servo system to adjust the throttle up and down. I identified the 2 wires (+ and -) that activate the servo clutch. Wired that to a 12-volt line, include a toggle switch on the dash, and wired the brake-light switch into it.

I just accelerate up to the throttle level I want to stay at, flip the toggle, and take my foot of the pedal. Works great. Hitting the brakes turns it off and I slow down just like in a factory cruise.

There were some technical issues, but it now works perfectly. I haven't tested my increase in economy yet, by taking a long trip. I did this mainly for the 10-hour drive down I-99 to Death Valley area that I do every year.

I don't know if this is doable with other makes of vehicles, but it should work with many older Toyotas at least.

[wyatta4]

That's awesome! Photos would be great!

[bobo333]

yeah great idea, would love some pics

[whitetoy]

Well, I didn't take any pics, but I'll add some tomorrow. Not much to show but the servo on the fender well, and toggle switch.

[Ecky]

In my Honda, the cruise control is a small box under the hood that has a cable attached directly to the gas pedal - it doesn't touch the throttle cable. I'm willing to bet I could grab the CC servo out of a car like yours and make it work in mine though.

[brucepick]

Nice work. Is your road trip coming up soon? Post again how it works out.

[whitetoy]

Originally Posted by Ecky

In my Honda, the cruise control is a small box under the hood that has a cable attached directly to the gas pedal - it doesn't touch the throttle cable. I'm willing to bet I could grab the CC servo out of a car like yours and make it work in mine though.

If you already have factory CC, I wouldn't mess with it. On flat highways, it would work almost as well. The servo unit from the Camry is pretty big and might not fit under your hood. Your Honda throttle cables would not be compatible, or be the right length, either.

[whitetoy]

Originally Posted by brucepick

Nice work. Is your road trip coming up soon? Post again how it works out.

Not until February, but I do play golf out of town occasionally, so that will be a good test. I have an Ultraguage installed, so I can the CC at the throttle position where I get the best instantaneous mpg.

It will be after the holidays, and better weather. Even though I'm in California, its raining like hell right now

[whitetoy]