106871-0511 ZEXEL INJECTION-PUMP ASSEMBLY Cross 1068710511

P-226: Fuel Pressure Sensor Test
The 3176 System monitors fuel pressure with a sensor located at the top of the fuel filter housing. The Fuel Pressure Sensor is supplied with 5.0 volts DC through the ECM Connector (J4/P4, Pin 10). The sensor return line goes through the ECM Connector (J4/P4, Pin 35). Both lines are also common with the Coolant Temperature Sensor. The Fuel Pressure Signal goes to the ECM Connector (J4/P4, Pin 39).Fuel pressure is regulated to a maximum of approximately 550 kPa (80 psi). Step 1. Inspect Connectors And WiringInspect the Fuel Pressure Sensor Connector (J16/P16) and the ECM Connector (J4/P4) and wiring between being sure to: * Check Connector lock rings.* Perform 10 pound pull test on each pin or wire.* Inspect wiring for damage or abrasion.* Inspect connectors for damage or corrosion. Refer to P-201: Inspecting Electrical Connectors for details. Repair any damage, then continue with the next step. Step 2. Check Actual Pressure With GaugeA. Install the 8T0846 Pressure Gauge (0 to 145 psi)(part of 1U5470 Pressure Group) on a "T" fitting with the Fuel Pressure Sensor.B. Start the engine and monitor the fuel pressure at low idle.C. Operate the engine at high idle and check the fuel pressure. Fuel pressure at low idle should be greater than 300 kPa (43.5 psi), and at high idle should be 550 85 kPa (80 12 psi) and remain steady. OK: Fuel pressure is within normal limits. Continue to next step. NOT OK: Fuel pressure is outside normal limits, is erratic or leakage is present. The problem is NOT in the 3176 Electronic Control System. Refer to 3176 Vehicular Diesel Engine, Form No. SENR4964, for Systems Operation, Testing & Adjusting, for help in identifying and repairing the cause of the problem. STOP Step 3. Compare Gauge Reading With ECAP/DDTA. With key OFF, install ECAP/DDT on the 3176 System.B. Start the engine and run at low idle. Compare the gauge reading with the display on the ECAP or DDT and record.C. Operate the engine at high idle. Compare the gauge reading with the display on the ECAP or DDT and record. The ECAP/DDT display should be steady and within 40 kPa (6 psi) of the gauge readings. OK: The Fuel Pressure Sensor is operating correctly. STOP. NOT OK: The ECM is not reading fuel pressure correctly. Continue to next step. Step 4. Check Supply Voltage To SensorA. With key OFF, install the 3-Pin Breakout "T" on the Fuel Pressure Wiring Connector (J16) ONLY. Do not connect to the Fuel Pressure Sensor Connector (P16) at this time.B. Turn key ON (engine off).C. Use the multimeter to measure the voltage between + V, Pin A (J16) and Return, Pin B on the 3-Pin Breakout "T". The voltage should be 5.0 0.5 volts DC. OK: The Fuel Pressure Sensor is receiving the correct voltage. Proceed to Step 7. NOT OK: Supply voltage is not reaching the sensor. Continue to next step. Step 5. Check Supply