Fuel Pressure Check

Using Fuel Pressure Gauge Set (100 589 13 21 00), connect gauge to hose line on fuel distributor (lower chamber). Connect other hose to fuel distributor (upper chamber).
Check system and lower chamber pressure with engine stopped. Pull off fuel pump relay and bridge the 2 terminals 7 and 8.
With engine at operating temperature, pull off electric connection on electro-hydraulic controlling element. Note position of pressure gage control valve.
Read lower chamber pressure. Nominal value at operating temperature should be approximately 6 psi (.42 kg/cm² ) below system pressure. When plugging in electrical connections, no pressure change should result.
NOTE: During warm-up stage, the controlling element is energized by a given current which is determined by coolant temperature sensor and ECU.
Pull plug from coolant temperature sensor. Make intermediate contact for test cable on electro-hydraulic controlling element. Using volt/ohmmeter connect leads to mA. switch on ignition and bridge fuel pump relay terminals 7 and 8. Read lower chamber pressure and amperage.
NOTE: When switching over from amps. to volts, pull off connecting lines from volt/ohmmeter.
Pressure for lower chamber should be approximately 78 psi (5.6 kg/cm² ) or approximately 5.8 psi (.4 kg/cm² ) below system pressure. Amperage should be approximately 75 mA.
If nominal value is not attained, check coolant temperature sensor (in case of warming up complaints), ECU and electro-hydraulic controlling element. If pressure in lower chamber is above nominal, check throttle (orifice) in fuel distributor for blocked passage.