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Fuelling and Emissions

A quick reference guide to each component in the Lucas Fuelling and Emissions range and what operation they perform.

Lucas Engine Management
Occupation Road
Hucknall
Nottingham
NG15 6DZ
England

Tel: + 44 (0) 1623 886400
Email: sales@smpeurope.com


Petrol Injection Filter The petrol injection fuel filter is fitted between the fuel injection pump and the fuel pressure rail, generally on the underside of the vehicle at the rear or in the engine bay on the bulkhead. It is advisable to change the fuel filter every 12,000 miles or every year as part of the vehicles routine service schedule.

Fuel Pressure Regulator

The fuel pressure regulator is located on the fuel rail on Mpi systems and in the throttle body on Spi systems. On some later vehicles it can be found in the fuel filter. It is designed to maintain a constant fuel pressure under hard acceleration.

The main reason for failure on these parts is a perforated diaphragm, which results in the injection system running at the higher pressure and over-fuelling the engine. The whole unit must be replaced on Mpi system whereas just the diaphragm may be replaceable on Spi systems.

EGR Valve

The Exhaust Gas re-circulation Valve (EGR) is fitted between the inlet and exhaust manifolds. This valve, under the right conditions, allows exhaust gas to be drawn into the inlet manifold, which displaces part of the air/ fuel mixture. This process is design to cool down the burning process and reduce Nox emissions.

There are two main reasons for failure of this part. The first is where the valve sticks open, this is due to a build-up of carbon on the poppet valve seat. The symptoms for this failure are poor running, lack of power and high fuel consumption. The second reason is that the valve remains closed due to a perforated diaphragm or failed changeover valve. The symptom for this failure is engine knock or pinking due to excessively high combustion chamber temperatures.

EGR Change-over Valve

The EGR change-over valve is located either on top of the EGR valve itself or on the bulkhead in the engine bay. This unit is a vacuum solenoid valve and is controlled by the ECU. It redirects manifold vacuum to the EGR valve under the correct running conditions.

Failure symptoms would be the same as an EGR valve, but you would alos have to check the condition of the vacuum pipes.

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