DME interchangeability?

[Babalouie]

Hope this isn't too random a question Steve (and others!)

This is the DME in my car, and my mech suspects that it's been chipped (the tester won't talk to it when he tried to do an idle adaptation). Part number is 911.618.124.03.


But I happen to have a spare, with a slightly different part number: 911.618,124.04, and it doesn't look like it's ever been tampered with.


Would these two bad boys be interchangeable on a plastic-manifold 964?

[Steve]

Yessir,...no problem.

The key here are the Bosch numbers (.450 & .473) and these two are interchangeable.

[Babalouie]

Thanks Steve!!

I'll swap 'em over and take the one in the car apart...very curious to see what's in there. My mech says that my car "feels" like it has a chip in it, due to the unstable idle (which he says he encounters all the time in 964s that have an aftermarket chip).




(I like the prompt service here)

[Babalouie]

Here's an interesting thought...the DME in the car (which is a plastic manifold car) is an "03" version, whereas the spare DME is an "04" and was connected to a alloy-manifold engine.

The 04 should be the newer version, right?

[Tom]

So I can learn... the 911. number isn't a problem, even though the other number starts with 964. ? interesting.

[Steve]

[Steve]

[Babalouie]

Thanks for your help, Steve. I thought I'd drop a line to let you know what I found

First, the DME that's in the car, which is the 964-part number.


It looked pretty normal, and I believe this is the stock eprom number?


But ironically, it's the spare older DME, the one with the 911 prefix part number..


Which has an aftermarket chip in it.


I've never used the spare DME (it came with a bunch of other random parts I have on the shelf) but it looks like the DME in the car, is stock.

[Steve]

Nice pics!

If your car has an unsteady idle with the stock chip, you have some resident issues that should be addressed. Some items that can cause such things are:

1) Old oxysensor
2) Old ignition wires
3) Old caps & rotors
4) Ignition faults with coils and ignitors
5) Intake vacuum leaks

Hope this helps,

[Babalouie]

Thanks again, Steve, I'll look into those things you mentioned.