leungwingkei

I have a auto 2002 Protege5. I understand how the cruise keeps the car at a specific speed when the system is turned on, and even on inclines it downshifts to maintain the speed it was set to.

I just want to know how it works on a car with a manual transmission. What happens when the cruise is turned on and the car goes up an incline? I assume that it does not downshift, but instead it revs higher to maintain the same speed. Am I right?
Looking forward to everyone's answer.

mesoh

yes, yes it does

David

yes

Toru

Yep, when you hit the incline it will accelerate until it senses that the speed is dropping then it will just cut out (as if you had pressed the clutch, brake or hit cancel).

As stated, pretty fricken' useless on hills.

tttP5

Also the cruise control is limited by the gear..... it won't engage in 4th... only in 5th.... I'm not sure if it is also limited by speed, probably works only above 60mph....

Davard

If the engine revs higher on a stick without changing gears, then the clutch is slipping.

Usually, when you first hit a hill, the speed will drop a little (since the CC can't see the hill and anticipate it and give a little gas as you hit the hill). Speed will increase slowly until it hits the preset speed. At the top of a hill, it usually overshoots the speed, as it can't tell that the hill is ending.

The limit of the cruise control speed is based on available vacuum. On flat ground, the CC on my Protege would work up to about 100mph. On a steep hill, it has cut out at 65 mph. Usually, that is what limits usage in hills. Cars that are geared tall (such as the already underpowered DX or 2nd/3rd gen LX), usually have to use too much throttle to maintain speed on an uphill for the vacuum-based cruise control to work.

And my cruise control ('90 LX) works from about 30 mph on up. And it works in any gear that you can use at that speed (1st is out, because it doens't go that fast). Newer cars may be different.

SO, if a hill is shallow enough, the CC will just add more gas to bring it back up to speed. If the hill is too steep, and the throttle opening needed to maintain (or regain) speed is too large, then it will disengage (due to lack of vacuum).