ECU Difference between 1994 964 and 1995 993

[drola]

Is there a big difference between the dme's of a 1994 3.6 in a 964 and a 1995 3.6 in a 993?
i know the 993 got more power from exhaust changes and probably software but not sure. also wondering if an aftermarket chip from the 94 would work on the 95?

[ian c2]

993 had Maf .

[Bill Verburg]

There is a big difference between the 964 and 993 OBD1 55pin DMEs, even bigger difference when the 993tt and US 993 changed to the OBD2 88pin Dme's
here are the pin outs for the various 55pin OBD1 compliant versions

and here are the pin outs for US 993 from '96


Internally there were multiple difference, some have Drive block some don't
all the 55pin versions have a user replaceable chip, none of the 88pin version do

55 pin, all '94 95 n/a, non vram 993 and all RoW '96-98 vram


1 year only 88pin US 1996 993 w/ twin chip design, non-flashable


'97-98 US 88 pin, w/ flashable chips

[drola]

wow Bill you never seize to amaze me with all your knowledge and the info to back it up
just out of curiosity, is the 1998 with tuneable chip more desirable or do people usually prefer the replaceable chip option?

[Bill Verburg]

Originally Posted by drola

wow Bill you never seize to amaze me with all your knowledge and the info to back it up
just out of curiosity, is the 1998 with tuneable chip more desirable or do people usually prefer the replaceable chip option?

The user replaceable chip design is only used in all '94/95 993 and in RoW normally aspirated 993. If you are a DiY'er then yes this is the way to go, I buy my chips from Steve Wong, you can get off the shelf tune or a custom tune based on dyno work(this is what I use)

The '97/98 design used on all US 993 from those years has flashable memory, but to get this done requires the professional removal(unsolder) of the chip, flash on specialized equipment, re install(solder). None of this can be done by the average guy in his garage.

[tshebib]

Sorry to hijack.

What pins would you tap into if you wanted to wire in a universal diagnosis port for a 96 US 88 pin?

[3rd_gear_Ted]

Originally Posted by tshebib

Sorry to hijack.

What pins would you tap into if you wanted to wire in a universal diagnosis port for a 96 US 88 pin?

next question:
what comm protocol or SW or ??? would work with what device to get codes??

[Bill Verburg]

Originally Posted by tshebib

Sorry to hijack.

What pins would you tap into if you wanted to wire in a universal diagnosis port for a 96 US 88 pin?

The minimum needed is the k & L lines & a ground

in the 964/993 there are also lines to the central informer, knock sensors & tach
I have the pins handy for a 964 but would need to do more research for 993(OBD versions will be similar to 964), particularly US '96 up

for a 964
port pin where it connects
7 DME13 L line
8 DME55 K line
10 CE31
12 CE30
14 DME6 revs
15 DME22 check engine control
19 DME22 knock

[drb930]

What would be the best ECU to use on a G-Body 3.4L 993 Plastic Intake Manifold conversion?