Hi Dave,
I had an aftermarket immobiliser/alarm fitted to my car too, I think the alarm may have been a Cobra but I cannot remember for sure. The immobiliser has long ago lost any label to indicate its origin!
By the time I owned the car, the alarm (located under the bonnet) had been disconnected, although I only discovered that later on as I removed the alarm box/speaker, then gradually removed all the rest of the wiring as I discovered the other ends were not connected to anything.
The immobiliser was separate. This is armed/disarmed by a chip that fits into a slot located near the ignition key - is this the same as yours?
Mine worked fine until about a year ago, when I suffered several occasions of failing-to-start then mysteriously jumping in to life, until one day the jumping-into-life bit didn't happen. With Tony (MetBlue)'s help we diagnosed this as the immobiliser. It simply interrupted the feed that should go to one side of the coil, sent the signal via the immobiliser then back to the coil. Re-connecting the wire directly to the coil as Lotus intended bought the car back to life.
Then, this New Year (following an abortive dash-out attempt to fix a leak that turned out
not to be the heater matrix after all!), the immobiliser decided to disable the starter motor. Again, the immobiliser simply interrupted one of the wires deep under the dash, I think it was the signal to the starter relay but can't remember. Again, removing the bypass and connecting the wires as Lotus intended restored life (after several frustrating hours of diagnosis). I recall the immobiliser wiring had been done using Scotchloks
.
I think the immobiliser is still inserted into the fuel pump circuit, so a thief may have spark and starter motor to start the car, but they won't get far. I should probably get rid of that too and return it all to standard, but I have too little time and higher priorities right now!
Wiring is not very helpful, as all the wires to the immobiliser unit are black! But essentially for each function affected (coil, starter, fuel pump) there are a pair of wires which break into the wiring that should be there. Probably a live and earth in there too.
Hope this is helpful.
