Hi there,

My Christmas present for myself this year is a retrofit of the OBC (On-Board Computer).

I bought all the pieces from a scrap yard and began the installation last night. So far, so good.

First step was to fit the outside temp sensor in the right wing mirror. That's when I realized the two wires for the temp sensor were not there. I took off the door covers and looked around inside the door. Nothing!

Poking under the dashboard didn't help either. There are dozens of cables there, but which one am I looking for?

According to the scrap dealer (a Porsche specialist) my car (1993 C4) should have the OCB wiring installed from the factory. Do you know how I can verify that?

Take care

 

964 turbo board might be a good place to ask

 

I did this about 18 months ago. IIRC All the wiring was there EXCEPT the outside temp sensor. I posted an idiots (i.e. me) how-to which hopefully should appear if you do a search. The main wiring to the tachometer should (if it is there on a '93, it was on my '91) be attached to the steering column with a plastic tag about half way down. I cannpt remember where the connector for the stalks was but it cannot have been hard to find.

 

Hi Tafkai and Ruairidh,

Thanks a lot for the advice. I will take the steering wheel off tonight and look for the cables. If need be, I will install the cables for the temp sensor myself.

I will let you know how it goes.

Take care

 

Horray!!!

I found the cables to connect the OBC Rev counter and the stalk switch behind the dash board. Great!

The OBC works except for the temp sensor. I will put in the wires myself this weekend.

However, the LED display is VERY dimly lit. I can hardly see it. Could it be a blown bulb?

 

My LCD display is pretty clear and not dim. But don't know enough about how they work to make any hlepful troubleshooting suggestion - sorry!

 

Yes, there are bulbs in the back for the backlighting on the OBC. If the bulb (I don't remember, but there might be two) is blown, you won't be able to read it very well.
-Eric
NER/PCA
90 C2 (with OBC recently installed)

 

Hi Guys,

Thanks a lot for the quick feed-back!

I strongly suspect that my OBC display bulb/bulbs are dead, so I will try to change it/them over the weekend. Are they the 1.5W type?

 

Does anyone happen to know if the dials from a 993TT will swap straight in for a set of 964 ones?

I have been offered some white dials with chrome rings on the inside of the glass. They look very smart but I am reluctant to commit to buying them without knowing if they will work properly, especially as they have the OBC which I currently do not have.

Also, if they will simply swap over, how much is the control stalk for the OBC?

 

Hi Jim,

I am not quite sure whether the instruments from a 993TT (=Twin Turbo, I suppose) are compatible with your normally aspirated 964. As far as I can remember, the functions for the OBC differ between the Turbos and the "normal" cars. I think you should ask your Porsche mechanic to be sure.

As for the control stalk, I bought it from a scrap yard along with the Rev Counter and another gauge for $450. I would be surprised if the stalk represents more than $50.

Take care

 

i think the only difference is you can display boost pressure on a 993tt guage

 

Jim, I also would check out whether the gauges work, IIRC the 965 OBC is (i) different and (ii) has less functionality than a 964s (I guess the boffins from Stuttgart wanted the 965 pilots to concentrate on keeping their blown beasties on the road and not worry about things like av fuel consumption!).

Control stalks also appear on eBay fairly regularly - generally sell for what the seller asks (there is not much bidding) I paid,IIRC something like $50 and then saw a couple not sell or sell with one bid at around $20!

 

Oh Jim, you also need to check whether your car is an early '91 or later one. Again, IIRC - (sorry I don't have time to check) the wiring was not present on MY90 cars so if your '91 was built as a MY90 you may not have the wiring....

Try a google search - there was a website out there with useful info. ("Stigs 964 pages"???).

 

Thanks for the answers guys, I will look into it a bit further. For info my car is MY91.

 

My MY90 C2 did have the wiring for the stalk, and OBC tach.........

-Eric
90 C2
NER/PCA