cruise control

[peter915]

Hi there,
has anybody had any experience with the cruise control only accelerating when activated?
On a 1986 3.2.
I read about resoldering every joint on the PCB, but is there a common fault here?
thanks in advance
Peter

[kodioneill]

pull out the ecu solider every join. it will work.

[Rot 911]

Mine does the same thing. Either a vacuum line leaking or you need to resolder all the joints unless you can find the microscopic crack with a magnifying glass.

[janz]

If vacumn and cable are good then I would send the brain out to Beckman Inds. for a rebuild. I had all sorts of problems with mine surging and not holding set speed so I went through the troubleshooting in Bentleys and from searches on this forum but could not figure out how to repair myself. I sent it out to Beckman and they rebuilt and tested the whole brain (mounted under the radio) and when it came back it worked perfect and still does. I think it was less than $200. and that included shipping and had it back in about 1.5 weeks.

[peter915]

Thanks Guys,
Living in Australia its a bit different; suppose I could try and borrow another brain and see what happens?
It would probably mean buying a secondhand unit from a wreckers - same age, same problems.
Janz - you mention Beckman - do you have any contact details for them - I could mail my brain PCB to them - not impossible.
PJ

[kodioneill]

buy a six dollar solider iron spend and hour, and solider the joins. use a fine pencil type not to much heat. what do you have to lose. just six dollars man.

[peter915]

Yeah I can try the re solder thing I suppose.
Having read Tims excellent article on the testing and fault finding at
Understanding the VDO Cruise Control Amp
It would seem far better solution to have the PCB completly overhauled?
if somebody does that?

[zzwhm]

On my 87 I had two problems, it would accelerate wildly and wouldn't disengage when I tapped the brakes. Clearly a bad combo. Turned out to be a faulty speed sensor causing it to accelerate and a bad brake pressor sensor preventing disengagement.

Assuming neither are your problem, +1 on Beckmann.
Bill

[janz]

Beckmann Technologies
3333 Industrial Drive
Durham, NC 27704

This is the question I asked of them and here is their response

VIN: WP0AB0919GS120890
Part Number: 928617127.00

Request: Can this non working cruise control "brain" be rebuilt? It's
for a 1986 Porsche Carrera. I have since bought a used one that works
but surges at a difference of 5mph. While I have this used working unit
I was hoping I could send this unit out to be rebuilt. What would be
the cost and turn around time?

That is a part that we repair. Cost is $161.25 with a 1-2 day turn
around. We can accept VISA or MCARD. If you would like to have it
repaired please send to

3333 Industrial Drive
Durham, NC 27704

With a not explaining that you would like it repaired and with your
contact information.

Thanks
Steve Marlow
Beckmann Technologies

Here is URL to web site so you can ask about shipping:
http://www.beckmanntechnologies.com/

Hope this helps, Good Luck and I love my 86

[janz]

One other note as I was trying to trouble shoot this problem I was told that if the speedometer was working Ok then my speed sensor was OK, not sure if that holds true for the 87 (different tranny).

[zzwhm]

In my case the speedo was messed up so its consistent with what you were told. Brake lights were intermittant as well. I never connected the problems until I replaced the switches and the cruise suddenly worked. Seems obvious in hindsight.

Beckmann rebuilt my cruise brain a long time ago. Still working.
Bill

[peter915]

Hi guys,
Today after looking on Google I found the following site:
http://www.injectronics.com.au/index.asp
It would seem they are the Bees Knees for repairing most automotive electronics & are here in Oz.
I have contacted them, as they list the control module as a stocked part item.
Their part number 92861712700CO

I assume this would be a remanufactured unit.
I'll post the answer here.
Their list of components stocked is very impressive.
PJ

[Otto]

We have been repairing these units for 20 years. We do most of the Bosch products.

[rgrimm]

The Bentley manual (and probably others) has a testing procedure done with a simple volt/ohm meter. After my replacement module died (I thought) I ran the test and it showed a back clutch switch. I'll dig into it in the Spring.

But it would try and hold for just a second, then let go. You could hold the stalk and it would accelerate, then let go as soon as you release it.