- the section of the supply pipeline is narrowed or the fuel filter is clogged;
- the power supply circuit to the fuel pump is faulty due to high transient resistance due to corrosion in the loop between the wiring harness and the fuel pump.
If the measured pressure is greater than 3.7 bar (kgf/cm), then turn off the engine and observe the change in pressure:
- if it has fallen to the nominal value (3.5±0.2 bar) it means that the section of the return pipeline is narrowed or it is clogged:
- check the fuel lines for squeezing and kinks, replace the damaged pipeline.
If the measured pressure remains high, then there is a high probability of a malfunction of the pressure regulator, it must be replaced along with the fuel filter.
Attention! If fuel leaks when the pressure regulator is removed, then there is a high probability that the return line is clogged.
If it is difficult to start the engine, then it is necessary to let the engine idle and turn it off. Take and record the instrument readings with the engine off. Take readings again after about 20-30 minutes. If the measured pressure has dropped by more than 0.5 bar, then:
- start the engine and let it idle to stabilize the pressure;
- stop the engine and use the tool «13.3.010» immediately pinch the supply hose directly in front of the pressure gauge;
- measure and record the pressure gauge reading;
- After about 20-30 minutes, read the pressure gauge again with the engine off.
If the measured value has fallen by less than 0.5 bar, the following faults can be assumed:
- failure of the supply pipeline;
- malfunction of the supply hose inside the fuel tank;
- Faulty fuel pump check valve.
Replace defective items. If the measured value then drops again by more than 0.5 bar, the pressure regulator must be replaced.
Attention! All fuel hoses and fastening clamps that were disconnected for inspection should be replaced.
After troubleshooting, read the information from the memory device (memory) ECU-ECU malfunctions of the DME system. Check error messages and correct them. Erase the fault memory of the ECU-ECU of the DME system.