WS4 Fuel Pressure and flow (Petrol only)

1 . Locate the two closest fire extinguishers?
Inside the work shop shed.


2 .If you can look up Fuel pressure specifications for the vehicle you testing?
 (265-304 k pa)


3 . Use eye protection Optional Relieve fuel pressure before installing pressure gauge.

4 . Attach fuel pressure gauge and notice which scale on the gauge will be using. Briefly turn key on or start the vehicle then turn it off. Check for fuel leak?.(NO)

5 . Measure the fuel pressure with the key on, engine off ?
Record it here(235 k pa )

6 . Idling Measure the fuel pressure with the engine idling Watch the pressure for a couple of minutes.
Record pressure here  (275 k pa)

7 . Maximum: With the engine idling, use the special tool to clamp the fuel return line?
Record pressure here (575 k pa)

8 . WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel pressure regulator?
Record pressure here(k pa)


9 . Residual: Turn off the engine, and watch the fuel presser for five minutes?
Record your Residual or rest presser here (300 k pa)


10 . Flow: Hook up proper equipment to read fuel volume if necessary.
Record flow gauge results of volume, or how much pumped in 15 seconds: (normal results may be 1/2 liter in 15 seconds)? 0.5 liter in 15 seconds.


11 . Replace vacuum lines. Carefully remove the fuel pressure gauge (between of fuel sparing into eyes, avoid sparks, etc ) Turn the engine key on and off, check for leaks. Start engine, check for leaks?
Check here No Leaks


12 . Explain why it is important to know a vehicle fuel pressure/flow?
Fuel pressure is critical for smooth functioning of an engine it is the fuel presser in the fuel rain that fuel injectors spray fuel according to the engine loads and speed for the best combination of power.


13 .Describe the symptoms a vehicle would give with each case low fuel pressure?
Low pressure makes the engine run lean may take long time to start it may misfire hesitate or halt.


Low fuel flow? 
Misfire, halt, hesitation 


High fuel pressure?
High pressure can cause an engine run rich the increases the emission from the vehicle and may cause clogging misfiring, racing.


Faulty fuel pressure regulator?
The engine may run rich because of high fuel pressure in the fuel rails or may run lean due to low pressure and for both these problems the above symptoms may be defected as fuel pressure regulator faulty which can not work with fuel pump to maintain a steady pressure relationship between the fuel line side of the injectors and intake manifold.