cschou

Hi there, and greetings from Denmark.

I own a Porsche 928 S4 from 1989, and have just done a auto to manual swap on it, using a 1990 GT as a donor car. And thanks for the tons of info found in thsi forum.

So far everything has gone as planed, but as I was doing some of the wiring, I found something in the Service Manual called the "Codierelement" in german. It's found on Diagram 10 in the upper right corner. (See picture)



Where exactly is this element fitted?

I know many others have done manuel conversions, have any of you changed this element?

Any further info on the "Codierelement" or Code element would be great.

Thanks

Regards Casper Schou

cschou

Can't seem to get the picture to work. Here's a direct link:http://billedeupload.dk/photo/2011-0..._0698.JPG.html

FUSE69

It's the coding plug, which is attached to the same bracket as the LH & EZK ECU are attached to... You need to change the configuration of that plug so that the ECU reads maps for a Euro Manual with Cat, instead of the original Euro Auto with Cat...

If you have the full WSM, there is a page in there that shows the plug and the different configurations of the pins, for the different car versions and markets

cschou

Thanks, I don't seem to have any more info than what is showed on my picture, but I'll try to change the plug from that info.

The fact that the plug is set to "Cat", is that specific the cat or more the O2-sensor?

I'm thinking of removing the Cat, building an X-over, but still fitting the O2-sensor. Should I set it to Cat or no Cat in that case?

Thanks

Regards
Casper Schou

Hilton

Hi Casper,

The info you're seeking is in the workshop manual. In section 1A, page 24-222.

If you don't have the manuals, you can download them on this page:

http://www.cannell.co.uk/Manuals.htm

If you're setting it to "no cat" you'll need to remove the O2 sensor, and add the factory potentiometer to the relevant harness connector in the passenger footwell (it'll be unused if your car previously had cats). Then you'll also need to adjust the idle mixture using the potentiometer to provide a baseline for MAF voltage as read by the LH ECU.

FUSE69

Below is the diagram for the coding plug... you need to add a pin, linking pin 1 & 7 to the new pin 3.
The plug set to Cat refers to using an O2 sensor, so that the Ecu uses a map enabling closed loop...

Easiest option is to set plug to cat and install O2 sensor... no problem to remove the cats if that's what you want... (other than the 'green' police, not sure what regulations are like where you are...)

Edit... MY 87-88 only...

Hilton

NOTE that Ben (Fuse) has posted the coding plug diagrams from 87/88 models. Do NOT use those diagrams in your '89 Casper - it will cause damage.

For 89 onwards, they're different, the pins are different, and the plug needs a resistor in it too. The 89 coding plug diagrams are on the page I referred to above.

Coding plugs from 87/88 are not compatible with those from 89-onwards - the wiring is very different (I burned a couple of meters of wiring making that mistake once).

cschou

Thanks guys, it really helped. I do have the manuals, just never found the page Fuse (Ben) is showing. Since I will still be using the O2 sensor I will simply set it to "Kat - M481" (manual) instead of "Kat - M249" (auto). As far as I can see in the wiring diagram (my picture) I only have to disconnect pin 3. For safety I will try finding the shown page in the manual and check.

I'll come back once job is done.

Regards Casper

cschou

sorry... I need to ADD a pin 3....

FUSE69

Crap, sorry....

MY 89+




Still, it should be just to add pin 3 to your existing plug...

cschou

I have now added a pin 3, put it all together again and it seems to be a succes. Engine started fine and ran properly. Although it also did in the auto-configuration. No burned wires or funny smells, so guess it's alright. Can't take it for a spin yet, still need a little bodywork, lights and the brakes. I assume I need to drive along to notice the difference between auto and manual mappings.

Thanks a lot Hilton and Fuse69 for your helpful and quick posts.

Regards
Casper Schou

Vilhuer

Auto and manual maps are basically same. Auto version just observes what gearbox is doing and acts accordingly. IIRR it will change idle rpm when gear is selected and change ignition timing when box wants to change gears.

cschou

okay thanks for the info, always nice to get a little more knowledge