Service manual

90-898303

4-5

Fuel Flow Component Description

Pulse Fuel Pump (d)

The pulse fuel pump operates through alternating crankcase pressure to

deliver fuel through the water separating filter to the vapor separator. Fuel

pressure @ Idle: 2 – 3 psi (13.8 – 20.7 kPa) [Minimum – 1 psi (6.9 kPa)]. Fuel

Pressure @ Wide-Open-Throttle: 6 – 8 psi (41.4 – 55.2) [Minimum: 4 psi (27.6

kPa)].

Water Separating Filter (e)

The water separating filter protects the fuel injectors from water and debris.

The filter contains a sensor probe which monitors water level in the filter. If

water is above the sensor probe, the warning horn will begin a series of

beeps.

Vapor Separator (h)

The vapor separator is a fuel reservoir which continuously blends and

circulates fresh fuel and oil.

1) Fuel Inlet – Fresh fuel delivered from the water separator by the crankcase

mounted pulse fuel pump. The amount of fuel allowed to enter the vapor

separator is controlled by a needle/seat and float assembly mounted in the

cover of the vapor separator.

2) Oil Inlet – Oil delivered by ECM controlled oil pump.

3) Fuel Pressure Regulator Inlet – Unused fuel/oil mixture being recirculated

from the

4) pump back into the vapor separator.

Final Filter (n)

The final filter is located above the electric fuel pump in the brass fuel fitting.

The filter collects debris and prevents them from flowing into the fuel rail and

injectors.

Electric Fuel Pump (Inside Vapor Separator) (j)

The electric fuel pump runs continuously while providing fuel in excess of

engine demands. The excess fuel is circulated through the fuel rail to the fuel

pressure regulator and back to the vapor separator. Normal fuel pressure is

41 – 45 psi (283 to 310 kPa).

Notes

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