Jaguar series 3, V12, starting problem

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Fri 2 Jul 2004 10:35
Jaguar series 3, V12, starting problem - jejr
Hi!

Can you help?

1991 Jaguar Sovereign 5.3 V12 Series 3 - starting problem
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My 1991 built Series 3 Jaguar Sovereign 5.3 V12 has a rather strange electrical fault. It had been misfiring intermittently and then stalled and refused to restart. The spark plugs were found to be beyond their useful life despite not having reached grand old age and changed. On trying to restart the car, after turning over the engine for about 5 seconds, the electrics shut down. The car was started by turning the ignition swith to II (to run the fuel pump) and bypassing the starting relay and the circuit that controls the relay - the engine fired straight away and ran smoothly.

The car was fitted by Lancaster Mayfair in 1991 with a Sonar Auto Alarm and we are wondering if the alarm has tripped and is somehow preventing the car from starting on the ignition switch. I have a FULL history of the car except for any details of the Sonar Auto Alarm but I know it is fitted as it is an invoiced item and the windows have stickers on them to show it exists and the siren is visible under the bonnet.

If any reader of this has any ideas a) how to disengage or reset the alarm or b) where the alarm is fitted to the car or c) any other ideas or experience of what might be the fault I'd be very grateful to receive their guidance.

I hope somebody can help!

Rgds
jejr
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Sun 4 Jul 2004 08:40
Jaguar series 3, V12, starting problem - Andrew Moorey (Tune-Up)
Not familiar with this alarm but does the alarm unit under the bonnet have a key slot under a rubber cover to switch it off? This will reinstate all of the interrupted circuits. If not suggest you get an Auto Electrician to remove it. Seems to be a common problem with old aftermarket alarms that the internal relays pack up.
Andrew


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