On my Euro 928S I have the cruise control unit, it doesnt seem to function properly and I have noticed that the tickover stays high when its been touched so I presume the cable is sticking

Whats the best treatment for this or do I just remove the system totally as it doesnt seem to be highly useful anyway

Suggestions welcome!

THanks
Paul

 

First try replacing the one-way vacuum valve located on the engine side of the 4-way vacuum line splitter coming off the brake booster.

Often times this is an easy solution to balky vacuum actuated systems such as the door locks, climate controls and cruise control.

 

The valve holds a good strong vacuum, if I undo this even after the car hasnt been used or run for a couple of weeks it still has a good vacuum.

The car 'sat' for a few years doing nothing which is why I presumed the cable was sticking at the motor end, on the throttle body its quite free.

What actually controls its position?

Thanks
Paul

 

Jack,
Normally the problem is the electronic control unit – Placed in front of the radio – I read some where on Rennlist, that re-soldering of the electronic board sometimes can solve the problem. I changed my complete control unit. Try to search on Rennlist
PS: On older cars, that can also be due a rusty vacuum servo unit

 

So far

Small vacuum pip from the 4 way vacuum line splitter is fine, cable is fine, control unit clicks when its operated, there are two larger vacuum pipes on the rear of this that connect to where?

The pipe is broken but I cant find the remains of what is was attached to

Any one know where its goes to and from

Thanks
Paul

 

Hi

Does anyone have a diagram of the 928 Cruise Control motor unit for a 1982 Euro

It has 5 connections

One electrical 2 pin which is OK

The cable which is OK
A small vacuum pipe from the 4 way splitter which is OK

and two larger pipes that join together and then this pipe is broken so I do not know where it should go or is from

Help with this would really be appreciated

Thanks
Paul

 

The two pipes are the breather - that is, when the unit is turned off, these pipes are the source of the air that kills the vacuum. They don't connect to anything.

 

Thanks Wally

One less thing to worry about!!!!!