1995 993 Dme

[fastbacker]

I'm looking to buy a 95 dme w/ a part #993 618 12 303.

I was hoping someone could tell me if this is the correct dme. I'm under the understanding that this dme should NOT have the drive block. Correct?

Thanks-
Craig Backer

[rattlsnak]

You should ask Steve at Rennsport. Mine did have it and I had to get a chip for it for my conversion. Dont confuse Drive Block with an Immobilizer system.

[fastbacker]

Originally posted by rattlsnak
Dont confuse Drive Block with an Immobilizer system.

I thought they were one in the same. Could you explain the difference please.

Thanks-
Craig Backer

[Lorenfb]

"Dont confuse Drive Block with an Immobilizer system."

They're the same system, i.e. the names are used interchangeably.

[rattlsnak]

My 95 has a "drive block" decal on it from the factory, and it does NOT have an immobilizer. Long story, its covered well on the rennlist board. Immobolizers interupt the starter circuit, drive block interupts power to the DME relay. On later cars, 96+, they names have kind of interchanged, but on the early cars, its more a function of the alarm module.

[Lorenfb]

"Immobolizers interupt the starter circuit, drive block interupts power to the DME relay."

A an old Mickey Mouse alarm unit, e.g. my 3.2, removes power to the DME unit.
An immobilizer and Drive Block are one in the same, i.e. they prevent the
engine from running by disabling (immobilize/block) the DME ECM INTERNALLY.
Some 993 engines with an immobilizer/Drive Block will crank but not start,
so that's NOT the key factor.

Most on the 993 Rennlist forum really don't fully understand the system as is apparent
from most of their postings.

[rattlsnak]

I went all the way to the training center here in ATL on this a few months back so im not going to argue back and forth on this, but the misconception is what is being called what. I can tell you that my 95 993 has a factory drive block decal on it, it is on the build sheet, and does not have an immobilizer. From 96 and up, you are absolutely correct. It depends if the immobilizer doesnt get the signal from the FOB or the Central Alarm Module gets a trigger as to which way it will not start. For late 94 and early 95 993s this is not the case. This is why you have to use the Porsche tester to set the Module for 'no remote' when you use a newer Alarm module (.03+) on an older car.

[Lorenfb]

"I can tell you that my 95 993 has a factory drive block decal on it, it is on the build sheet, and does not have an immobilize"

So, for a 10+ year old car, who knows what was there originally. The sticker is meaningless.

The fact is that the alarm unit and the immobilizer (Drive Block) units are separate units.
An alarm unit by itself can ALWAYS be bypassed easily to start the engine. It's only
by sending an enabling code to the DME that a true immobilizer (drive block) function
exists.