Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Constant-Throttle cruise control

whitetoy · 12-21-2012, 07:19 PM

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.

12-21-2012, 07:19 PM	#1 (permalink)
whitetoy EcoModding Lurker Join Date: Jun 2009 Location: California Posts: 6 Thanks: 0 Thanked 3 Times in 2 Posts	Constant-Throttle cruise control 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.