Hi all,

I have problems with on-board computer in my '91 3.3T.
It shows turbo pressure and outside temperatue fine, but trip meter and digital speedo are on zero... dead.
Analogue speedo and odometer works fine.

What can be wrong with it?

Thanks,
Troky

 

Dear Troky,
Only one of two things. You have dropped a wire off the back of the Tacho or the OBC speed section has failed. Most likely the second one I am afraid. Such a failure is not uncommon.
I would get out your owners manual and run through the selection and reset process for each function.
Ciao,
Adrian
964C4

 

Hi Adrian,

I checked all wiring and it seems to be ok.
Can you help me out with that second thing you said? Problem is that I don't have owners manual (btw, where can I get one?).

Thanks,
Troky

P.S. I received your book today... great job!

 

Dear Troky,
You have to use the mode selector on the steering column and see what you get at each selection. You just cycle through them. You write down if you have;
Numbers (info)
dash lines (loss of info)
blank screen unable to display info
You reset at each selection by pulling the control stalk towards you (position 4) and holding it there for more than 3 seconds.
After a reset and th car not moving of Average fuel consumption, average speed and trip meter should read
Dashes
Dashes
0.0

To select each function in turn move the control stalk up (pos 1) to go through the functions anti-clockwise or down (pos 2) to go through the functions clockwise.

I have no idea where you can get an owners manual from for your Turbo.
I think they are available in the USA. www.my-porsche.com rings a bell.
Ciao,
Adrian
964C4

 

Troky,

you could try Mathew at TYPE 911 (www.type911.co.uk) , he should be able to get you a manual if he doesn't already have one in stock.

Best regards and good luck

Emilios

 

Adrian,

I resetted all functions already... 0.0 for trip meter, dashes on avg.speed and 0 on speed (turbo doesn't have avg. fuel consumption in OBC).

BUT... trip meter doesn't count (always on 0.0) and speed is always 0. It seems that OBC doesn't get pulses at all. All wires have good connections. It would be very helpful to know what wire is 'pulse-in' and where is it coming from.

I will check those links for owners manual.

Thanks,
Troky

 

Troky,

I have a manual with my car, and there's precious little more info on the OBC that Adrian hasn't given you in his answer above.

 

John,

Can you tell me what it is?


Trroky

 

Dear Troky,
John is saying that there is nothing else anyone can tell you.
The speed calculation circuit of the OBC has failed. The input is from the speedo head. Speedo still working, ABS still working then the OBC has failed.
Ciao,
Adrian
964C4

 

Adrian,

So what's the solution? To buy new OBC?


Troky

 

Yep! or do without it. As long as the boost indicator works that is all you really need. If you can borrow an OBC tacho to check if it is wiring or the instrument do this. 99 times out of a 100 it is the instrument.
Ciao,
Adrian
964C4

 

I think I'll have to do without it. There are only 2 965s in Croatia AFAIK... Well, anyway, thanks for all info and advices.

Troky