Detroit Diesel — Test #5: Leak Test
Testing & diagnosis · Fuel system
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Check engine oil for presence of fuel.
Procedure
- Remove the engine trim panel and disconnect the Fuel Temperature Sensor; plug it into the wiring harness.
- Install the adaptor and seal from the fuel adaptor parts kit (J-46377); attach banjo fitting, high-pressure fuel line (J-46372) and gauge (J-46378).
- Disconnect the fuel return line at the main filter housing and seal with a cap; attach hose with banjo fitting and shut-off lever.
- Open the fuel fill cap; fill the low-pressure fuel circuit with compressed air until gauge reads 1,000 kPa (145 psi).
- Turn the shut-off lever OFF and wait five minutes; gauge should read at least 975 kPa (141 psi).
- Check the engine oil for presence of fuel and correct any problems.
- Open the shut-off valve, remove test equipment, reconnect lines and Fuel Temperature Sensor.
Tools required
- Fuel adaptor parts kit J-46377 Amazon
- High-pressure fuel line J-46372 Amazon
- Gauge J-46378 Amazon
- Compressed air Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Fill 1,000 kPa (145 psi)
- After 5 min minimum 975 kPa (141 psi)
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.