Main Menu

cruise control

Electrical and Electronic

Model: 911, Year:1987, Mileage:90000, Type of use:Street use only
My Cruise Control accelerates when set then sags down below the set speed and accelerates back up, etc. This oscillation is similar the one described in a 10/30 2007 Q&A. You recommended checking for vacuum leaks and slack in the CC servo cable. I can't hear any leaks and I can't see the end of the vacuum hose that goes to the servo, but it seems OK. I tightened the cable from the servo a little bit.. The problem remains.The clutch switch is sticky, I have to pull up, just a little to get it to open before setting the CC. I can't see how that is the cause of the problem. It looks to to me like an typical unstable servomechanism in which it overshoots, then passes through a dead zone and then tries again to lock up, but overshoots.I bought a rebuilt unit from Programa. It was worse. It only worked in accelerate mode. I.e. if you released the switch lever after attempting to set it, it shut off!HelpHoward Salwen

You must log in to view answers associated with technical questions. Join PCA to participate in our community.
No votes yet