JPTas wrote:Hi guys,
Been trawling through the posts on immobilising E30s and I keep seeing reference to the 'green loop' behind the glovebox taped to the loom. I haven't quite figured out exactly what this does, other than that it has something to do with a factory option immobilisation circuit? (Fuel pump relay related?)
Pardon my ignorance, but is it not a simple matter (if you were a thief) of separating this plug from a connected immobiliser and fitting a loop of wire to activate whatever is being immobilised? Would it not be better to solder a connection upstream of this 'loop' point? Or do you figure if they got that far they'll get past it anyway?
Also, I've started to fit an alarm/immobiliser system to my '89 325is (Aus) by connecting to wires next to the steering column, but I'm now thinking from comments here that it is better to do it behind the glovebox?
If my immobiliser has two normally open immobilisation circuits, what's the best way to attack immobilising the car? I've read the guru Brianmoore's comments on grounding fuel pump wire being better etc, but I don't quite get how to do this.
BMW have provided a socket above the glovebox which is simply a break in the ignition feed wire to the engine loom. On cars with no factory fitted immobiliser this socket has a plug inserted into it which has just a short loop of green wire connected between its two pins to complete the circuit. If the car has a factory fitted immobiliser, the alarm unit will be plugged into this socket, and the loop of wire with a plug will just be tied up to the loom nearby.
As you say, this is easily bypassed. Most easily by a wire from the battery + terminal to the + terminal on the coil.
Your immobiliser most probably has two normally closed contacts, which open when the alarm is activated, not normally open.
These are best used to break the ignition circuit, as per factory alarm, and to break the feed to the fuel pump, which is a green/purple wire coming down the snorkel tube from the fusebox to behind the glovebox, and then disappearing behind the LH speaker panel.
Earthing the fuel pump wire is better than open circuiting it, because if an attempt to bypass the immobiliser is made by linking the coil to battery, then the fuel pump fuse will blow, giving the potential thief even more problems. To do this, you will need an immobiliser with one normally open or a changeover contact.
I was down that way in June and could have dropped by.