IXLR8

Bill, now you know why I "personalized" my system.

Something that is "factory", everybody knows about. As for "custom", there is only one-off.

993/907

This seems too good to be true!
I'll give it a try in a month or so and report back.

Will I be able to unlock the door with the key, start her up and go? Lock it with the key....no more fob?

Lorenfb

"You don't even need the chip"

That's only the case if the vehicle doesn't have an immobilizer, which is
different than just having an alarm unit, as the immobilizer communicates
with the DME ECM to allow the engine to run (not just preventing cranking).
For the '96 and later 993, a major DME ECM mod is required, hardly a DIY!

993/907

Now we have come full circle.
Steve Wiener told me last year that it's probably not worth the effort to de-mobilize the immobilizer on the '95 cars.....later years can be flashed to eliminate it, but not the '95MY.

Bill Verburg

the unlock signal comes from pin 14 of the immobilizer and goes to pin II/2 of the alarm. the alarm then internally connects pin I/6 & I/4 to power pin 27 on the DME

when all is said and done the DME only needs +12v to pin 27 to start and run

the other issue is the relay R61 which also needs a signal from the immobilizer. R61 is a relay w/i a relay. The inner relay is the actual starter relay, the outer needs to be jumped to eliminate the immobilizer function

Bill Verburg

The OBD2 US cars are wired differently than US OBD1 '95/'96 and OBD1 RoW cars. I didn't look at their wiring diagrams.

Lorenfb

"The OBD2 US cars are wired differently than US OBD1 '95/'96 and OBD1 RoW cars. I didn't look at their wiring diagrams."

Whatever!

Bottom line: If the 993 ('95) has an immobilizer (not just an alarm unit),
the immobilizer CONTROLS the DME ECM via the 'W' line ('K' via the
immobilizer) and just powering pin 27 will NOT allow the engine to run.

Bill Verburg

that's correct, the arm/disarm signals are passed to the immobilizer that way
the immobilizer then signals the alarm via pin alarm pin II/2 to unarm the system. The alarm then sends signals via connector X4/1 pin 10(under the drivers seat) to DME pin 27, this is a T15 item which wants +12v for position II & III of the key to run & start respectively

the immobilizer also energizes pin15 on the immobilizer to send +12v to the inner relay of dual relay R61, when this is energized it alloys the key III position to energize the outer relay of R61

so 2 things need to happen to bypass the immobilizer
1) jumper at R61
2) energize DME pin27 w/ +12v this is the part I am unsure of, some sources say that a chip that is not expecting an immobilizer signal is needed. If so then this part is not necessary, but if not true then the DME pin 27 needs to be energized when the key is in pos II

Loren if you have other insights I'm open minded and will look into them, I do value and appreciate your input. I know that this can be done from sources at shops that have done it.

Lorenfb

"if you have other insights I'm open minded and will look into them"

Please refer to the 993 wiring diagrams, "911 Carrera (993) Model 95/2 Sheet 11"

There you'll see signals (K data line & W line) besides the signals to the
alarm unit (lock dstr. & unlock dstr.). The W line directly controls the
DME ECM and allows the engine to start. Yes, pin 27 needs 12 volts too,
but that's NOT enough when the DME ECM is coded for an immobilizer.

Again, please refer to the wiring diagrams and not what may have been
posted over on the 'Dark Side' where 95% of the info is hearsay, hyperbole,
and not reliable.

Bill Verburg

Yes, I've been looking at the wiring all winter

OK that agrees w/ what I was told, that you need a chip that is not coded for the immobilizer. That's easy because I already have one in there.