WS4 Fuel Pressure and flow (Petrol only)

WS4 Fuel Pressure and flow (Petrol only)

Fuel Pressure and flow (Petrol only)

Warning, be careful around raw fuel. It can catch fire! Use appropriate safety precautions.

Keep sparks, flame, your body and your clothing away from raw fuel! Know where your fire

extinguishers are and use them if necessary.

1. Locate the two closest

pin, squeeze the handle, and spray at the base of the flame.) Write down where they

are:

2. If you can, look up Fuel

you can’t look them up, make a guess at the fuel specs you should have and write

them down here:

38 - 44 PSI i got this specification from the manual

3. Use eye protection.

gauge. Or there will be some fuel that sprays at you as you attach the gauge. You

can relieve pressure by several methods: 1) To relieve the fuel pressure. Make sure

you have a rag to catch the fuel, start the engine. 2) Remove fuel pump (circuit

opening) relay or fuse and run the engine until it stops, then crank to check that the

engine doesn’t start 3) Use a vacuum gauge on the pressure regulator to lower fuel

pressure, or 4) Open a fuel line at some pressure point and catch the fuel in a rag

beware there may be lots of fuel.

4.

Briefly turn key on or start vehicle, then turn it off. Check for fuel leaks.

Are there leaks? Yes .................... No no leaks.

If there are leaks you must correct them and retest before continuing. If you need

help, ask !

5.

Record it here: 35 PSI (also record the units you are using, psi, bar,

Kpa, etc…) 250 Kpa

With key on recording the fuel pressure is 35 PSI.

Idling: Meassure the fuel pressuere with the engine idling watch the pressure for a couple minutis.

Record pressure here: 37 PSI

                                          At idling 37 PSI

Maximum: With the engine idiling use the special tool to clamp the fuel return line .

Note: this can only be done for a short period.

Record pressure here 87 PSI

                                 Return line with clamp 87 PSI

WOT: With the engiine idling , disconnect and plug the vacuum line going to the fuel

pressure regulator.Record pressure here 45 PSI

Residual

Record your : Turn off the engine, and watch the fuel pressure for five minutes.residual or rest pressure here 40 PSI

      After five minutes engine turn off got 40 PSI

Replace vacuum lines. Carefully remove the fuel pressure gauge (beware of fuel

spraying into eyes, avoid sparks, etc.) Turn engine key on and off, check for leaks.

Start engine, check for leaks. No leaks? Check here:

Replace cap over fuel pressure test port. Check when done: done OK

Make sure the vehicle is safe and runs fine when done, or tell your instructor.

12. Explain why it is important to know a vehicle fuel pressure/flow?

This  is important to know about the vehicle fuel pressure because low or high pressure may effect the engine performance. High pressure push more fuel in the injectors and makes the engine run rich and low pressure makes it run lean and also that test faulty pressure regulator, also fuel pump the fuel pump woking or no and how is the pressure.

13. Describe the symptoms a vehicle would give with each case:Low fuel pressure: The engine will run lean and the oxygen sensor will give send the signal to ECU to reduce the amount of air so makes the throttle more close  even there is high demand of air for engine performance

Low fuel flow: The engine will run lean and the oxygen sensor will give send the signal to ECU to reduce the amount of air so makes the throttle more close  even there is high demand of air for engine performance

High fuel pressure: High pressure put more fuel in the injector so makes engine run rich and so oxygen sensor will sense that there is shortage of air and will send the signal to ECU to send more air in and hence effect engine performance

Faulty fuel pressure regulator: Faulty regualtor extra fuel will not return to tank it cause more fuel pass to injectors engine shold runing rich , high HC coming out form the exhauct .With the engine idling, use the special tool to clamp the fuel return line.