VS V8 BT1 Immobiliser Issue

[stuntmanmike]

Hey Forum members,
I have a terminal issue with my VS BT1 V8 and I just don’t know how to diagnose this before taking it to an auto-sparky and possibly spending big $$$. This would be a first for me not being able to fault find an automotive electrical issue. Can anyone can provide their two cents on what it could be?

It started out a few weeks ago with the starter motor not kicking over from time to time. Disconnecting/reconnecting the +ve terminal of the battery seemed to resolve this. Sometimes when the key was turned I could hear a loud click from somewhere (perhaps a switch/relay) and the interior light would not switch on and the dash lights would not come on when the ignition was switched on. Turning the key to the “ON” position didn’t do anything when this happened. Dead everything! Swapping a relay on the relay assembly (next to the battery in the engine bay) would resolve this. Sometime disconnecting/reconnecting the +ve battery terminal fixed this somehow.

Now, the car has a brand new battery to begin the defect elimination process and the starter motor worked heaps well but the engine does not kick into life. I squirted some fuel into the inlet manifold to see if this was related to the fuel system and still nothing. I now was thinking that perhaps this is ignition module/coil/distributer related? Then, a few minutes ago I heard that tell tale click from under the dash or somewhere when trying to start the engine. Now there are no lights lighting up the lower dash cluster and the starter motor doesn’t engage when the key is turned. I can hear the relays clicking twice when I move the key to the “ignition on” position but the fuel pump doesn’t whir for two seconds like it did before. I’ve tried to play with the +ve terminal of the battery and swap some of the relays for new ones. Still nothing. I’ve got a can of petrol and match to burn the car. I’m tempted…

Has anyone experienced this at all with their VS?

Surely the issue is something simple. It’s not the battery or the starter motor or the relays or fuses IMO. I reckon the key ignition barrel or factory immobiliser is rotten. The central locking works well from the key remote so perhaps the key battery is not a root cause. I hope it’s not the ECU or a short somewhere. I’ve scanned the forums, googled for it, read the Max Ellery front to back and asked the old man for advice.

If this info helps then a few days ago before the new battery I ran the engine, hit the high beams and had the engine stall as soon as the high beams lit up. Up till that point the car ran when the starter motor kicked in. Now nothing… WTF?
Sorry for the long winded blog as I am stumped on what this could be. I am peeved with this fault!

 

[accentstencil]

I doubt it's the immobiliser because even with the immobiliser on the engine should still turn over but not start. I would be looking for a bad earth perhaps.

 

[stuntmanmike]

Thanks accentstencil,
I've traced the fault to a short and rectified that. Your advice was just what I needed.
Now the dash lights come on when the ignition is turned to the "ON" position and the starter motor turns over. The engine doesn't kick into life and I don't mind for now as I feel that the solution is closer.
I'm going to try keeping the key in the "ignition ON" position for 2 hours as I've read in the forums elsewhere and see if that has an effect. We'll see...

 

[accentstencil]

Thanks accentstencil,
I've traced the fault to a short and rectified that. Your advice was just what I needed.
Now the dash lights come on when the ignition is turned to the "ON" position and the starter motor turns over. The engine doesn't kick into life and I don't mind for now as I feel that the solution is closer.
I'm going to try keeping the key in the "ignition ON" position for 2 hours as I've read in the forums elsewhere and see if that has an effect. We'll see...

Is the security light in the mode switch flashing when you are trying to start it, if so the immobiliser is not turning off.

 

[stuntmanmike]

Okay. Here's the synopsis:
The immobilser was not functioning well due to a short in the circuit that has luckily been traced and rectified. accentstencil was 100% correct with the diagnosis and now the immobilser seems to work well.
The non-starting issue was traced to either the ignition module or ignition coil. I replaced and relocated the coil (for improved access in the future) and found that the engine would not start. I changed the ignition module although the original unit showed "power" with the test lamp. And that was it; The engine fired right up.
Thanks for your assistance with this as the flashing red light on the radio surround fascia had me stumped when the problem became evident and was partially faulted by the immobiliser not wanting to deactivate.