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Diagnostic Manual, Engines, Volume 2

3.2 LH Sequential Multiport Fuel Injectin System (LH-SFI) > 32 Hydraulic Test Program - Test (Fuel System Pressure and Internal Leakage Test)

Hydraulic Test Program - Test (Fuel System Pressure and Internal Leakage Test)

Test step DTC	Test scope	Test connection	Test condition	Nominal value	Possible cause/Remedy 1)
1.0	Fuel pressure at idle ( with vacuum)	Pressure gauge connected to test connection.	Engine: at closed throttle speed Valve on pressure gauge closed.	3.2 - 3.6 bar	Check fuel pumps 34 , Replace diaphragm pressure regulator.
2.0	Fuel pressure at idle ( without vacuum)	Pressure gauge connected to test connection.	Engine: at closed throttle speed Disconnect vacuum hose from diaphragm pressure regulator.	3.7 - 4.2 bar	Replace diaphragm pressure regulator.
3.0	Fuel system internal leakage	Pressure gauge connected to test connection.	Shut off engine. After approx. 30 minutes	> 3.0 bar >2.5 bar	If pressure drops quickly, replace check valve in fuel pumps. If pressure drops slowly, check injectors 36 , Replace diaphragm pressure regulator or O-rings on diaphragm pressure regulator.

1) Observe Preparation for Test, see