cruise control accelerates when engaged
 

I have a 84 carrera and now when i engaged the cruise control it starts accelerating and doesn't stop unless i turn it off...anybody know why this might be happening

Thanks in advance for the replies

Jay

Your car is telling you that you drive too slow.

The cruise control brain on these cars are pretty notorious for needing rebuilding. Probably that...

(But to work up a "care" as the concept of cruise control on one of the worlds most responsive driver's cars is pretty ridiculous.)

Send your cruise control module off to the guy in this thread. Many folks have had good luck with him. Think he charges about $80 now.
Ninety five percent of a cruise problems are due to deteriorating solder
connections in the cruise module. Good luck!
http://forums.pelicanparts.com/porsche-911-technical-forum/851491-new-cruise-control-repair-guy-block.html

Also make sure that the linkage in the engine bay is not hung up. There is a thread on cruise controls that talks about daisy chaining zip ties to prevent the cable going to the throttle from jumping out of their holders and getting stuck on full acceleration, similar to yours.

http://forums.pelicanparts.com/uploa...1504539903.jpg

That's a good tip about the cable fix, but the OP stated that it stops accelerating when he turns it off, so it seems it's not the cable problem.
I have had the same accelerating symptom he has, and it was a bad module.
That "runaway" acceleration due to the cable problem is a real white knuckler! Need to be fast in turning off the key!

Thanks for the replies.I sent the module off about 5 years ago due to surging and it worked for a while and then the surging started again and now it just accelerates when engaged.I guess i'll have to send it out again.

The brain. That's what they do. Even when refurbed I've had them be ok for awhile then they flake out again. I am literally on brain 4 or 5 in 13 years, two of which were refurbed then eventually went bad again. At least three did the uncontrollable accelerate failure symptom.