Fuel Pressure and Aeration CheckPurpose
Check for correct fuel pressure and fuel aeration.
lters or separatorsmounted on vehicle will in
uence fuel pressure,restriction, and aeration.
Fuel Aeration must be checked using theFuel Pressure Gauge clear hose. Aeration cannot bemeasured using the FDP sensor.
• ZTSE4681 – Fuel Pressure Gauge• ZTSE4925 – Clean Fuel Supply
1. Connect Fuel Pressure Gauge to the fuel test porton the front of the intake manifold.2. Route clear hose into diesel fuel container.
The fuel pump will only run for 10 seconds per switch cycle, and there must be 10 seconds betweenswitch cycles.
The Fuel Delivery Pressure (FDP) sensor is only capable of measuring up to 517 kPa (75 psi)of pressure, even though fuel pressure normally operates at 621 kPa (90 psi).3. Turn ignition switch to ON, engine OFF. Measure fuel pressure with shut-off valve closed. Open shut-off valve momentarily to check for possible aeration.4. Record results on Diagnostics Form.• If fuel pressure is below speciﬁcation, go to Fuel Filter Check• If fuel is aerated, go to Aeration Check