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Fuel Pressure Control System Inspection: Troubleshooting

NOTE: Before using the following flow, check to make sure that battery voltage is higher than 11 V. If battery voltage is low, pressure becomes lower than specification even if fuel pump and line are in good condition.
FUEL PRESSURE - TROUBLESHOOTING CHART

Step Action YES NO
1 
  1. Install fuel pressure gauge, referring to FUEL PRESSURE INSPECTION .
  2. Operate fuel pump.

Is fuel pressure then 250 - 300 kPa (2.5 - 3.0 kg/cm 2  , 35.6 - 42.7 psi)? 		 Go to Step 2. Go to Step 5.
2  Is 180 kPa (1.8 kg/cm 2  , 25.6 psi) or higher fuel pressure retained for 1 minute after fuel pump is stopped at Step 1?  Go to Step 3. Go to Step 4.
3 
  1. Start engine and warm it up to normal operating temperature.
  2. Keep it running at specified idle speed.

Is fuel pressure then within 210 - 260 kPa (2.1 - 2.6 kg/cm 2  , 29.8 - 37.0 psi)? 		 Normal fuel pressure. Clogged vacuum passage for fuel pressure regulator or faulty fuel pressure regulator.
4  Is there fuel leakage from fuel feed line hose, pipe or joint?  Repair or replace. Go to Step 10.
5  Was fuel pressure higher than spec. in Step 1?  Go to Step 6. Go to Step 7.
6 
  1. Disconnect fuel return hose from fuel pipe and connect new hose to it.
  2. Put the other end of new return hose into approved gasoline container.
  3. Operate fuel pump.

Is specified fuel pressure obtained then? 		 Restricted fuel return hose or pipe. Faulty fuel pressure regulator.
7  Was no fuel pressure applied in Step 1?  Go to Step 8. Go to Step 9. (Low pressure is measured.)
8  With fuel pump operated and fuel return hose blocked by pinching it, is fuel pressure applied?  Faulty fuel pressure regulator. Shortage of fuel or fuel pump or its circuit defective. Refer to FUEL PUMP CIRCUIT INSPECTION .
9 
  1. Operate fuel pump.
  2. With fuel return hose blocked by pinching it, check fuel pressure.

Is it 450 kPa (4.5 kg/cm 2  , 64.0 psi) or more? 		 Faulty fuel pressure regulator. Clogged fuel filter, restricted fuel feed hose or pipe, faulty fuel pump or fuel leakage from hose connection in fuel tank.
10 
  1. Disconnect fuel return hose from fuel pipe and connect new hose to it.
  2. Put the other end of new return hose into approved gasoline container.
  3. Check again if specified fuel pressure is retained.

While doing so, does fuel come out return hose? 		 Faulty fuel pressure regulator. Fuel leakage from injector, faulty fuel pump (faulty check valve in fuel pump) or fuel leakage from fuel pressure regulator diaphragm.
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