speed control

[Nick Triesch]

I have been fixing stuff on my 85 911. Next thing to tackle is the speed control. I notice that I can increase the speed with the little lever, it holds for a moment then drops off. So if it speeds up then part of it must work right? I see the speed unit on the back of the engine compartment on left side. Everything looks good and hooked up. One of the large hoses back there seems to have a cut in it. Don't know for sure if it part of speed control. What do you think? Nick

[Wil Ferch]

Can't help you directly but if your problem ends up being electrical, see here especially post #3. Search also under keywords "Tempomat" or "speed-control".

Understanding the VDO Cruise Control Amp

[DRACO A5OG]

Hey Nick,

A picture will help allot.

If you see a tear in a hose, replace it. If it is the vacuum for the cruise control, it will need that to set the proper speed desired.

J

[Mitch Leland]

Nick,

The large hose could be a breather hose, is the cut all the way through? Like Draco said, a picture would help. Regarding your C.C. it sounds like you have a vacuum leak. Do you have a Bentley's Repair Manual? You need to identify the hoses that are part of the cruise control system, then be sure the hoses are fresh and tight.

I have a pretty good working C.C., but it can be set a 70 MPH and over a 30 minute period it will slowly drop off 2-3 MPH so it will need to be bumped up to maintained the desired speed. It's still a nice feature on an old car for an old shoe...