Inlet Throttle (ILT) Modulator (Emission control - Td5)

The EGR modulator is located on a plate fixed to the inner wing on the RH side of the engine. The modulator is attached to the plate by two through-studs, each with two nuts which secure the modulator assembly to a rubber mounting which helps to reduce noise. The modulator must be mounted in the vertical orientation with the two vacuum ports uppermost.

The modulator operation is controlled by a signal from the ECM which determines the required amount of EGR needed in response to inputs relating to air flow and engine operating and ambient conditions. The modulator has a black two-pin connector at its base to connect it to the ECM through the engine harness.

Each modulator features three ports: l The top port of the EGR modulator is identified by a white band and connects to a 'T'-piece in the vacuum line via a small-bore brown plastic hose. On type 2 systems the brown hose is connected in parallel with the vacuum source to the ILT modulator.

The other two ports on the 'T'-piece connects vacuum line hoses of black vinyl tubing between the vacuum pump and the brake-servo assembly attached to the bulkhead. The vacuum pump end of the vacuum line tubing terminates in a rubber elbow, which gives a vacuum tight seal on the suction port of the vacuum pump. The brake-servo end of the vacuum line tubing terminates with a non-return valve in a plastic housing which plugs into the front face of the brake-servo housing. l The middle port of the EGR modulator is identified by a blue band and connects to the suction port on the EGR valve through a small-bore blue plastic hose. l The lower port of the EGR modulator is identified by a green band and connects to atmosphere through an inline filter via a small-bore green plastic hose. On type 2 models a 3 way connector is fitted to vent both modulators through a single filter. The other port of the in-line filter vents directly to atmosphere.

The blue and brown vacuum hoses are protected by corrugated plastic sheaths. The ends of the hoses are fitted with rubber boots to ensure vacuum tight seals at the component ports.

Inlet Throttle (ILT) Modulator

1 Port to vacuum source (white band) 2 Port to ILT valve (blue band) 3 Port to atmosphere via in-line filter (green band)

4 Harness connector (green)