2nd Gen Non-Engine/Transmission Cruise Control Surge

[jraker]

All,

I noticed a problem with my cruise control as soon as I did my power mod. I engage the cruise and it is constantly cycling. It will build boost and then drop and then build boost again even though there is no hill. I can keep it more constant with my foot! This was just annoying me before but now it is really annoying. My wife is pregnant and the motion makes her a little sick. Seems like the cruise is out of sync with the rest of the system. Has anyone ever run into this? This problem existed the moment I put the Banks system on. I thought I read a thread about this before and I can't seem to find it. Maybe it was buried in the Catcher Monster string. Maybe I just imagined it. Any help is appreciated.



Thank you,



Joel

 

[RustyJC]

Yep, the power mods throw the calibration of the cruise control off. Briefly, if the CC is set at 70 MPH and speed drops to 69 MPH, the ECU will call for more fueling to bring the speed back to 70 MPH. Unfortunately, the ECU will send a signal for X more fuel, but the power mods cause actual fuel flow to increase by, let's say, X + 20%, and the speed will overshoot. When this happens, the ECU will send a signal to cut fuel by Y, but actual fuel flow may be reduced by Y + 20%, so speed undershoots and the cycle starts again.



If you happen to have a vacuum actuated cruise control, you can dampen this surging by putting a needle valve in the vacuum line to the CC actuator, then keep pinching the needle valve down to dampen the CC actuation function. If, like me, you have the fully electronic cruise control, there's not much that can be done about it.



Rusty

 

[rono]

Mine does the same thing. When I had my six speed I did not have that problem. I knew the problem was caused by what Rusty described but did not know any way to stop it. I may either have to live with it or go back to my six speed.

Ron

 

[KB0OU]

Mine is worse, when I engage CC it keeps increasing speed, anybody know how to fix that????????

If I push the right button (Set/Coast) it will slow down as long as I hold it, if I push and hold the Resume/Accelerate button it will speed up faster so it is all working. When I set it it will start speed where I set it, then slowly increase speed until I shut it down.

Please tell me how to fix this thing!!!!!