3.6 conversion immobiliser install

[RL technical]

Hi guys have fitted a 964 motor to my 77 coupe, I basically have the car running bar an idle problem seperate issue. I want to install an immobiliser however would like to know how and where I tap into the dme control circuit to cut fuel and spark, in a neat manner, I've got the power and earths and central locking working but now want to cut the fuel and spark, attached is a photo of alarm diagram.

[rattlsnak]

As far as I can tell, you are not wanting to install a factory immobilizer, but an aftermarket one that interrupts the circuit.? (sorry, hard to read that schematic unless I stand on my head.. wait. I see where you are located now.. I get it.. ! Ha! )

If that is the case, where did you put the DME relay for your conversion? Most people put that under the drivers seat and you can tap right into the fuel and spark control circuit right at that point.

[IMR-Merlin]

The problem is you are reading it upside down...

[IMR-Merlin]

I dont see where there is a starter cut or anything like that in the unit itself. I do see that there is an armed (-) out on pin #8 that you can use to run a relay that will interrupt an ignition or starter circuit.

Brendon

[RL technical]

Ok yes I did install the dme and motronic under the passenger seat, remember we are r/h drive over here. So what I'm wanting to know. Is which terminals on on 964 dme do I tap into & what's the best way to connect them.

[rattlsnak]

If you want to interrupt the power feed coming into the relay, then tap into pin 30, if you want to interrupt the output, then tap into pins 87 and 87a, if you want to tap into the DME control circuit, then tap into pin 85b. That being said, the main power feed, pin 30, would probably be easiest.

[ischmitz]

Pin 3 from the 55-pin DME connector runs through the DME harness to pin 2 of the 14-pin connector under the driver's seat. From there it runs on to the DME relay socket Term 85b and turns on the 2nd stage (fuel pump, etc) when motion on the flywheel is detected. Interrupt that line somewhere and you have your immobilizer.

Personally, I'd stay away from the main power since you would need to control 20+ Amps and your unit might not be up to that task even if it has an internal relay. Further wrestling with 4mm wires requires some skills in soldering and if improperly done adds safety hazards (poor joints warm up and cause cable insulation melting, etc.)

Ingo

[RL technical]

Ok I'm going to give that a try, def don't want to be switching 15/20 amps through immobiliser, all I want to do is cut the control side, anyway il give it a go on the weekend.
Btw how hard is it to get your hands on a Bosch hammer?