I'd be interested, but I have an 84, which means, I had to solder my new chip in. It's in to stay. I'd have to unsolder it and put a holder in there in its place. I haven't gotten around to it yet.

i found this thread very interesting this morning so i thought i'd give it a try...my car is a '86 Calif. but with a Automotion/Weltmeister chip. So far i can't tell any difference...maybe with the stock chip? Is the aftermarket chip negating any benefit of unplugging the brown wire?

FR is correct, however, the 911 has only 1 pin input to the DME, so I do not see how you get 4 possible configurations in a 911. (This would require 2 inputs to the DME, and that MAY be the case in a 944). It was my understanding that the different ignition maps were possibly selected by using the rotary switch that is mounted on the digital board.
In the 911 28 pin chips there are, in fact, three maps for ignition only and 1 map for fuel. For all the hackers out there, the following is the Hex address where each array begins:
Ignition Part Throttle: 12A6h, 16F2h,1880h (12x12 array)
Ignition Idle: 136Ch,17B0h,193Eh (10X1 array)
Ignition Full Throttle: 1348h,1794h,1922h (16x1 array)

Good luck-

My 1985 is a Cali Carrera with a stock chip. Unfortunately, it's at the shop getting aligned. When it comes back, I'll be sure to try out this modification.

Until then, as a SW engineer I am most interested to read about the various hacking going on...

Even though I have an SC, I have been following this post with interest.

Great information and since Tony started the process it looks like he should get the Carrera Nobel prize.

Pin 28 on my DME harness goes to the Altitude Correction unit...Is it possible that, based on altitude, a different ignition map is selected?

so in my california 89, running steve's chip, would the connected/disconnected status of the brown wire matter? will it give the same relative change to any chip in the dme, or does the chip have to be specifically written for it?

bump for the definitive answer??

My car had been running so bad for so long... Until I recently disconnected the bad wire.... Now it runs great??

Correction... Bad Brown Wire...

Reviving an old thread, bump again to learn more about this. I am showing on paperwork that my car was delivered to NY and then brought into California in the mid 90s. Does this "brown wire" have an effect on the car? I will look later on to see if its connected or not connected. I have an 84.

Yes!
Disconnect it & see for yourself!!!

Is this the right "brown wire" ? I can't see anything else without taking out my seats.

http://forums.pelicanparts.com/uploa...1134450833.jpg

http://forums.pelicanparts.com/uploa...1134450855.jpg

I believe it is. I don't know for sure, but after reading this thread I went out and checked and mine was still connected (strange for a car originally delivered in NJ...). I disconnected it and will find out more on the drive to work tomorrow...

ianc

84 Porsche,

I believe the wire (pair) in your picture is for the altitude sensor (that silver cylindrical thing to the left of the DME in your picture)?

On my '84, the California wire is a single wire (as opposed to a pair). It is located (and protruding from) the wiring harness at the DME connector. It may even be taped to the harness.


For me, I can readily see and disconnect it when viewing the DME and harness underneath the drivers seat from the front of the seat. Remove your drivers side carpet. Voila!!!

Hope this helps.

Regards,
Carlton

I just went through this. That is NOT the correct place! Those wires are for the altitude sensor (round thing on the left).

Look instead from the front of the seat. The big bundle of wires that has the plug on it, connects to the DME. You should see two brown wires, the ends of which may be taped to that harness. Unwrap the tape to reveal the ends of those wires. There is also a clip bolted to the floor that might be in the way. A 10mm nut IIRC. Remove the clip to make it easier to remove the tape.

My car is an 87, not sure if the 84 is exactly the same. Mine were already unplugged (non Ca car.)

Can anybody post a pic of this please?

Guess I'll have to reconnect my altitude sensor now... ;)

ianc

Best I can show at the moment is the first picture in this thread:

http://forums.pelicanparts.com/porsche-911-technical-forum/255434-what-these-wires.html

See the brown wire that is coming out from the connector? There are two like that. Trace them towards the driver's door. If they are covered in tape at the ends, unwrap and take a peek. Each wire ends in a plastic connector.

Me too. I got up this morning pulled the carpet and reconnected the altitude sensor. I guess we are both learning this the difficult way. It is tough to get under sport seats though. I have learned to stay quite flexible in attempting to work on my car.

It's the thin little brown wire that is all of about 3 inches away from where the wiring harness connects to the DME, and just in front of the DME Relay.

Steve Wong even chimes in about it here.

http://forums.pelicanparts.com/uploa...1134499578.jpg

.