OK, my car is now a 100% complete swap as everything works and nothing is bypassed or disconnected.

I just got back from a 700 mile round trip and the cruise control is, well, stupid. I've also noticed it before when I was making 371HP with the old rotary that it will "porpoise" by accelerating hard to reach cruise speed, overshoot, coast and undershoot, then accelerate hard again. This normally occurs for the first couple of miles, then it will settle down and cruise as it should.

Does anyone know of a way to modify the cruise control to not be so damn jumpy? I've been considering finding an ABS car and swapping the wheel sensors to mine and tying them into the F-Body traction control system, which if I recall - also is the cruise control system on the F bodies. It would add the cool feature of traction control (which I don't have a problem with) and hopefully cruise correctly as it was designed for 300+ lb/ft and not 150.

How do the rest of you with high HP TIIs deal with settling down your cruise control?

 

How do you mean jumpy??? I am assuming you mean it pulls fast and that this is a non stock piston motor being used in a FC.

Is it possible that the trottlebody you are using has weak return springs (return springs not as heavy as Mazda)???

 

Yes, it accelerates really hard in 6th

Good call on the throttle spring. I hadn't thought of that one. I'll have to go find a pull scale (not sure of it's correct term) and measure the TII vs my LT1 and see what the differences are. I'm not sure that would be a definite fix on it though as even with other modded TIIs I've had, the same symptoms existed.

 

Machining a smaller cruise actuator pulley was discussed on another forum. I may attempt this over the weekend and see how it works out.

When I do come up with a solution, I'll make sure to let everyone know so they can apply the same fix to eliminate their cruise problems. Regardless of what powers these cars, once the power level is raised they all exhibit this problem.

 

I know on an aftermarket cruise system I had on another car there was a "sensitivity" adjustment.. It helped stabliize, and keep it from doing the "hunting" that you're describing... I dunno if stock has that, though.