Underwood's Porsche 944 Site. How to get at, and replace, the DME
box/EPROMs in your Porsche 944/951.
Bill's Porsche 944 Site -- Removing and Replacing the DME (or the Chips Inside It)
To replace your DME chip, or to find out if the chip in your car is original or aftermarket, you must locate, remove, and open the DME computer box or "brain". This removal procedure applies to any 944. The actual Porsche chip part number given below are specifically for an 85.5 car, and is probably valid for all 85.5 and later US 944 2.5L NA 8-valve motors.
1 - Disconnect the battery (important; you don't want to fry anything!)
2a - On late models (85.5 and later) peel back the passenger's footwell carpeting. It is held in place by velcro near the top. Underneath, you'll find the DME. It's the silver metal box. To remove the DME, there are 8 screws on two different mounting surfaces, as I recall. In this area you will also find wood as a material Porsche used in your car. If you know how to use a screwdriver you'll figure it out. On the 951, there are 2 control boxes. The larger one is the DME "main brain" computer. The smaller one is the KLR unit.
2b - On early 944's (pre 85.5 changeover) the DME is located in the driver's footwell area, to the left of the steering column. It is attached to steel brackets in four places. To remove the bolts, get a flashlight and prepare to crane your neck removing it!
3 - Disconnect the big cable (look at it; it pries off from one end to the other, lengthwise) and remove the metal DME box.
4 - Carefully pry back the several little tabs holding the metal box halves together.
5 - "Open" the DME box like a book. Be gentle, as the ribbon cable that connects the halves is the book's "spine".
6a - The chip in 85.5 and later cars is a 24-pin device in a removable socket. It has a silver label on it with part number 1267355189 (P/N is from an 85.5 chip I have in a little anti-static case). If the label looks like anything else, it's not an OEM Porsche chip. You might be able to figure out who makes it by the numbers on it. For instance, my AutoThority chip for 85.5-87 944 8-valvers is AutoThority P/N 9126.96.36.199.
6b - The chip in pre-85.5 cars is soldered to the board. To upgrade you usually need to send the DME in, and it gets returned with a daughterboard added containing a new, socketed chip.
Good Luck. I have replaced the DME brain in 3 944's and one 951 so far...
It's a LOT easier than replacing belts...