Seemingly ridiculous DME question.

Hi I bought a 2002 996.2 yesterday 3.6 Tip (for my brother, and yes he is paying me back, he hasn't seen the car in the flesh yet). The car is a very interesting but not straightforward proposition and I will do a post on it when it is delivered on Wednesday. The car does not have it's ECU for some reason and I would like to attempt a start post some basic further inspections. Will the ECU from my 2.7 Facelift Tip Boxster and alarm and transponder allow me to start the car without damaging it or having any unforeseen consequences? Of course I know it will at the very least have the wrong fuel map on it. The ECU is the same part number 996.618.604.00 and I know for a fact that with the 996 3.6 Tip flash on it it should work fine. And before anyone says, yes I know it is better to get hold of the proper flashed ECU, alarm and keyset, but I just want to start the car. Just by coincidence I bought another 986 2.7 Facelift (manual) ECU Alarm keyset yesterday morning (for my Boxster) not even knowing the 996 was missing its one. So ECU's seem to be featuring quite heavily in my Porsche life at the moment. I will need to find a friendly garage who can do some PIWIS flashing for me at some point. Thanks guys! Berni

I have only ever heard of swapping like for like full alarm/ECU set so maybe you will be able to answer your own question when you fit it?

Hi Thats for sure, but apart from sufficient fuelling to make the engine run, I was wondering about the actual mechanical differences the engines have. The 3.6 has the two valve timing and lift mechanisms whereas the 2.7 has just the one. Time will tell as you say. Berni

First off i would want to know why the car is being sold with no ECU on it .. perhaps a wiring issue which killed it. In this case all you will accomplish is killing your Boxster ECU , possibly the alarm control unit .. that will certainly be incorrectly coded if nothing else . If the car doesn't start as its from a different car then what have you proved other than it will spin over . part numbers may well be the same .. software and wiring wont be .. as mentioned one is variocam plus which the other isn't . Tip or not won't matter .. its coding . I would strongly suggest you check the dme pinouts on both cars to confirm there isn't a positive or indeed a negative in a different place . I can confirm that fitting a new control unit to a car with a wiring issue will kill it .. been there and done that .. also killed the car i borrowed it from .. i was following instructions though i'll hasten to add !! Would i do this ? not a chance .. it may well work .. it may well fire up .. is it a risk ? hell yes ! Your choice young man

Hello deMort Thank you for your input. Yes, I am also wondering why the DME was missing. In fact strictly speaking it wasn't. It was in the boot along with some other bits and bobs. The problem was that it is a DME from a 2.5 Boxster. How crazy is that. Also the alarm was in bits under the (dry and unbolted) passenger seat. So there is a mystery to solve for sure. Thats not the whole story though. I will reveal more when I get the car. EDIT: I will be checking the pinouts. Great idea. It just so happens that my Boxster DME is already faulty (I burnt out an o2 circuit), so if I blow the whole thing it wont be the end of the world. I will be cautious. I have a replacement set arriving already. I will be properly checking the engine over before I attempt a start so may not even get that far. Thanks again Berni

I hope you didn't pay much because this car sounds like it has horrors hiding.

Maybe a good candidate for a Megasquirt ECU?

A truer word never spoken. It arrives tomorrow so we will know a lot more then! So exciting haha! I looked up megasquirt a long time ago when I was going to fuel inject my 1970's Lotus Elan +2s using fireblade throttle bodies. I still have them actually. All the best Berni

Fireblade throttles on the 996? Sounds like a great project!