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4.6 Litre RANGE ROVER WITH GEMS ENGINE MANAGEMENT (from 1995)
- Possible ECU failure symptoms


The GEMS system introduced with the 'new shape' 4.6 litre Range Rover is an integrated engine management system (combining for the first time ignition and fuel injection functions in one box) and replaces the earlier Lucas 14CUX system. Please click here to see photo of this ECU.

The ignition part of the GEMS system comprises 4 coils, each providing a spark to 2 cylinders simultaneously on the wasted spark principle. (each spark plug is fired twice per cycle, once on compression and once on exhaust - the spark during exhaust cycle is not needed eg. it is 'wasted'. This system saves costs as one coil can be used for 2 cylinders.

The fuel injection part is genuine multipoint ie. each cylinder injector is operated independently of the others and for the first time, Range Rover have an engine management system that is capable of controlling engines on a per cylinder basis.

GEMS is controlled by, and communicates with the BeCM and is integrated with the vehicle security systems.

To date, GEMS appears very reliable and the only common problem appearing is ECU damage following work on the catalysts or oxygen sensors. The symptoms of this are rough running on one bank of cylinders following work on the engine.

Please click here for full address and repair quotation form.

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