Fuel Pressure
- Disconnect circuit opening relay. See CIRCUIT OPENING RELAY LOCATIONS table.
- To bleed down fuel in system, start engine (if possible) and allow to die. Connect pressure gauge to fuel line at fuel filter. Reconnect circuit opening relay.
- Install EFI Pressure Gauge (T80L-9974-B) to relief valve. Relief valve is located on fuel supply manifold.
- Turn ignition on. Use a jumper wire and connect terminals of Yellow fuel pump check connector together. See FUEL PUMP CHECK CONNECTOR (YELLOW) LOCATION
table. If pump does not run, check fuel pump circuit and circuit opening relay.FUEL PUMP CHECK CONNECTOR (YELLOW) LOCATION
Application Location B4000 Left Inner Fender Panel, At Rear Of Battery Navajo On Firewall, Near Windshield Wiper Motor - If possible, start engine. Check fuel pressure with vacuum connected to and disconnected from pressure regulator. See REGULATED FUEL PRESSURE table. Turn engine off and disconnect jumper wire at fuel pump check connector. Wait 10 minutes and ensure residual pressure is at least 21 psi (1.5 kg/cm2 ).
- Operate fuel pump by jumpering fuel pump test connector. Check fuel pump performance. Pinch hose between pressure gauge and fuel filter. DO NOT hold longer than necessary to check pressure. See FUEL PUMP PERFORMANCE table. If pump does not meet specifications, check fuel pump circuits, fuel pump, fuel tank, fuel filter and repair or replace as necessary.
FUEL PUMP PERFORMANCE
| Application | Pressure | ||
|---|---|---|---|
| B4000 & Navajo | (1) | ||
|
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REGULATED FUEL PRESSURE
| Application | At Idle W/ Vacuum: psi (kg/cm2 ) | At Idle W/O Vacuum: psi (kg/cm2 ) |
|---|---|---|
| B4000 & Navajo | 28-37 (2.0-2.6) | 38-46 (2.7-3.2) |
NOTE:
Fuel pump control unit terminal identification is not available.