DMEHacking

DME Hacking - '84-'89 Carrera
Last update 7/1/04

I've started messing around with my car's computer (DME) for fun.
If you are doing this also, what I discovered may be of interest to you.
I am not an expert.
I know zip about reprogramming DME's.

This is what I've discovered about the '84-89 Carrera DME hardware so far:
- The '84-89 Carrera DME used some sort of (custom?) 8051 CPU
- '86 CPU part # is "BI 26052"
- '88 CPU part # is "B573306".
- '89 CPU part # is "B57312". The "B" stands for Bosch I guess.
- My '86 DME uses a 2716 EPROM that holds 2K bytes.
- My '89 DME uses a 27C64 (B57477) EPROM that holds 8K bytes.
- If you swallow your DME unit do not induce vomiting. Call a physician immediately.
- By moving a jumper you can run a 2732A EPROM in an '86 DME. Instructions
- Connecting the battery up backwards can zap the EPROM and leave the rest of the DME unharmed.

Tim Polzin has discovered some more interesting stuff - like how to update an earlier box to '88-89 specs, See Tim's post to Pelican .

EPROM Table '84-'89 Carrera

DME
Year EPROM type EPROM# Notes

1984

EPROM not socketed?

1985

911.618.111.??
85-86 24 pin, 2K (1) 1267355102

911.618.111.08
83-85
24 pin, 4K (2)
1267355211
231 hp Euro (930/20)

911.618.111.12

24 pin, 4K (2)
1267355211
231 hp Euro

24 pin, 4K (2) 1267355302 217 hp US (930/25) Late '86 early '87?

911.618.111.18
85-86
28 pin, 8K (3)
1267355357
231 hp Euro (930/20)

911.618.111.19
85-86
24 pin, 4K (2)
1267355301
"Low Fuel Quality", fuel quality switch at pos 4 Euro (930/20?)

911.618.111.19
88-89
28 pin, 8K (3)
1267355357
"Low Fuel Quality", fuel quality switch at pos 4 Euro (930/20?)

911.618.111.20
88-89 28 pin, 8K (3) 1267355358 217 hp US (930/25)

DME	Year	EPROM type	EPROM#	Notes
	1984			EPROM not socketed?
	1985
911.618.111.??	85-86	24 pin, 2K (1)	1267355102
911.618.111.08	83-85	24 pin, 4K (2)	1267355211	231 hp Euro (930/20)
911.618.111.12		24 pin, 4K (2)	1267355211	231 hp Euro
		24 pin, 4K (2)	1267355302	217 hp US (930/25) Late '86 early '87?
911.618.111.18	85-86	28 pin, 8K (3)	1267355357	231 hp Euro (930/20)
911.618.111.19	85-86	24 pin, 4K (2)	1267355301	"Low Fuel Quality", fuel quality switch at pos 4 Euro (930/20?)
911.618.111.19	88-89	28 pin, 8K (3)	1267355357	"Low Fuel Quality", fuel quality switch at pos 4 Euro (930/20?)
911.618.111.20	88-89	28 pin, 8K (3)	1267355358	217 hp US (930/25)

(1) 2716 24 pin, 2K bytes
(2) 2732A 24pin, 4K bytes
(3) 27C64 28 pin, 8K bytes Eprom # B57477 = 27C64

Note: A big thanks to Michel Bartholomé for supplying lots of Euro chip data, the years, and engine numbers.
Note: Thomas (Tim) Polzin has created a much more complete listing. See Tim's Pelican Post

DME Pages from Factory manual

DME '84-86 P28-2
DME '87-89 P28-2b
DME Jumpers P28-2c

DME Hacking Links:

Steve Wong has been researching the maps. He posted some of his results on the Pelican 911 list. Check It Out! OEM, Autothority, Weltmeister chip maps!
Marc Skarshinski has written a DME Editor. You can download it here.
FR Wilke's 944 Motronic DME web site has lots of interesting info and a schematic for the 911 DME you can download.
Protomotive has a trial version DME Editor you can download. The download also includes the contents of 4 US Eproms.

If you have more info to share feel free to email me at chris@a3ds.com

Back to Messin Home Page