1997 DME for 3.4 swap
 

Hi, my DME is the early one that is not programmable. I’m eventually swapping the motor to 3.4, so planning to buy a DME from 1999 996 with cable throttle. But until the engine swap, I want to get the programmable 996 DME for remap and to delete SAI/ 2nd O2 sensors to run my original 2.5 engine.

How do I get the 996 DME paired up with an immobilizer on my car?

Any other issues that I need to work out?

Thanks!

What is the number on Your original DME ?
0261...

026 120 460 4

Does 1999 DME from 996 plug and play? Or do I need to match it to the immobilizer first? Assuming that the 996 DME is programmable, my plan is to buy the 2.5 tune for upload, then take it out to restore to 996 tune when I eventually do 3.4 conversion.

From the little experience I have. You'll need to pair the immobilizer and the DME. The 3.4L and 2.5L with cable throttle bodies have similar DME firmware/software but of course the tune is different.

Do you plan to flash the whole chip with 2.5L info or just the tune? If its just the tune then you'll run into some issues. The maps/tables are not in the same places and can vary even from one 2.5L DME to another.

Wish I can see this not programmable DME.

DME You got ...604 , is the same i have. It lacks downstream CAT O2 sensors, SAI pumpm, and maybe something else too...

It is tunable for sure, You can flash it by obd2 plug (partial 16kb) or on the bench (pins) full flash.

I have Yet to test if it will start with 3.4 file flashed in 2.5 ecu. I guess, even if it does , it will complain about the things it misses.

Since the injectors are the same on both engines, i suggest You skip on buying 3.4 ecu for now... There are probably folks around who can make anything You might need for the 3.4 later,,,,

My car is US spec. with SAI and 4 O2 sensors…

No from what I read, this DME must be sent to a specialist for tuning, so I assumed that simple flash through OBD2 port is not possible and that’s why nobody sells one either.

I’m very uncomfortable to mail out my DME for tuning as it will be a nightmare if lost…. Therefore trying to see if I can buy a used DME from later 2.5 that is capable of OBD2 flash.

Let me know if I’m missing something here.

Okay maybe I misspoke, what I meant by ‘not programmable’ is more like ‘not flash-able through OBD2 port. So if I pick up a later version of 2.5 DME that can be flashed, I needs to match it with the immobilizer on my car or it won’t work, right?

For a 1999 engine you'll need a 7.0 DME.

A 1997 986 will have a 5.1 DME - not compatible, because it hasn't the correct in- and outputs. Also the engine wiring harness is different.

If you get an 7.0 DME from a 986 the mapping needs to be flashed for a 996 3.4 engine. This can't be done by OBD. This always needs to be done on the bench.

Check what alarm control module you have. If you have a M531, you'll need to update to an M535. If you have a M535 it can be reprogrammed to work with the newer DME.

If you need to update from M531 to M535 the wiring harness has to be updated too.

I'd buy a full set like this. After the 3.4 is installed and verified good, I'd sell the 1997 set that was originally in the car to recoup my cost (because I'm cheap like that).

http://986forum.com/forums/uploads02...1650115192.jpg


Autobahn Parts - Electrical, Porsche 911 996 OEM 1999 Carrera Alarm Control Module + ECU + Tumbler w/ Key, 996.618.601.04, 996.347.017.07, 996.618.260.05

or

https://www.ebay.com/itm/334397963288? *Their eBay feedback is a bit low for my comfort, but reading the details they seem legit.

It's been a couple years since I looked at it, but I think the only difference in the wiring is an additional shielded wire for the antennae connection. If needed, I have a harness in a 2001 parts car that should have it.

Don't think M531 will work with a 7.0 DME, because of different memory controller.

Easiest might be to have a totalled car with a known good 3.4 engine, where you can all the parts and wiring you'll need.