Test 2A: Test Fuel Pressure and Internal Leaks of Fuel System

Test fuel pressure and internal leaks of fuel system


Question: Can the vehicle engine be operated at idle speed?

No

Figure legend





- 001 Sockets of component N3/10 (ME-SFI control module)
- 05 35-pin socket box
- 043 Pressure gage
- 050 126-pin socket box
- 055 Measuring beaker
- 069 Pressure hose(119 589 04 63 00)
- 108 Test cable N3/10 (ME-SFI control module)
- N3/10 (ME-SFI control module)
- II 1/63 Connection Test cable
- II 64/126 Connection Test cable

Test sequence
- Switch off ignition.
- Connect test pressure gauge.
- Connect socket box to component N3/10 (ME-SFI control module).
- Insert bridge:
- [5.5] 5<-->97 [4.12]
- Switch on ignition.
- Note: Component M3 (fuel pump) runs

Specified value
- Pressure [3.7...4.2] bar

Question 1a: Is the measured value okay?

No 1a
- The measured value is not o.k.
Possible cause and remedy
- N10/2f4 (Fuse 4)
- N10/2kA (Fuel pump relay)
- Test current comsumption of component M3 (fuel pump)
- Fuel filter with integrated pressure regulator.

Yes 1a
- The measured value is o.k.

Test prerequisite
- Test pressure gage is connected

Test sequence
- Switch off ignition.
- Insert bridge:
- [5.5] 5<-->97 [4.12]
- Switch on ignition.
- Note: Component M3 (fuel pump) runs
- Switch off ignition
- Remove bridge

Specified value
- Pressure after 30 minutes: [> 2.5] bar
Question 1b: Is the measured value okay?

No 1b
- No further information available

Yes 1b
- No further information available

Yes

Figure legend




- 043 Pressure gage (103 589 00 21 00)
- 055 Measuring beaker
- 069 Pressure hose (119 589 04 63 00)

Test sequence
- Switch off ignition.
- Connect test pressure gauge.
- Engine at idle speed

Specified value
- Pressure [3.7...4.2] bar
Question 2b: Is the measured value okay?

No 2b
- The measured value is not o.k.

Possible cause and remedy
- Test current consumption of component M3 (fuel pump)
- Fuel filter with integrated pressure regulator

Yes 2b
- The measured value is o.k.

Test prerequisite
- Test pressure gage is connected

Test sequence
- Run the engine for a short time and switch off again.
- Ignition: OFF

Specified value
- Pressure after 30 minutes: [> 2.5] bar

Question 2c: Is the measured value okay?

No 2c
- The measured value is not o.k.

Possible cause and remedy
- In the event of slow pressure drop:Check component Y62 (Fuel injectors)
- In the event of rapid pressure drop: Diaphragm pressure regulator
- M3 (fuel pump)

Yes 2c
- The measured value is o.k.
Further possible causes of fault
- Test delivery of component M3 (fuel pump).