I recently lost 1 and 4, due to an ECU fault. My car is a 97 vx with a 3 wire coil pack. It original had a Vector, that was removed by Caterham, and then a local installer fitted a Meta. When I removed the original Engine Loom for the ECU replacement I found some original Vector wiring in the lead between the coil and the ECU, but they had not immobilised the whole coil just one side. If your installer has just used the original Vector connection points then you probably have half your coil being powered through the new immobiliser and half not. Now assuming you have the original ECU, and MBE 906, this could put extra load on the coil pack drivers and cause them to fail. If they fail the chip is obsolete (first built in 1984 and stopped production in 1987), and you will be in the game for a new ECU.
I would recommend you speak to the installer and find out how he installed the immobiliser, if they cut into the pink or purple wire from ECU to coil pack get then to remove it. Immobilise the white ignition power wire to the ECU relay (not on wiring diagram, but the top relay), used to switch the ECU on, and not the power supply to the ECU instead.
After spending some time looking at the loom of my car, I am going to have to spend some time tidying things up over the winter, after Caterham and the other Immobiliser installer has had a go at it.
Hope this helps
Chris....
H15 SVN Get it !