Fuel pressure and flow (petrol only)
Make :: Toyota
Model:: 4A-FE
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 fire extinguishers. (If you have to use it remember to pull the pin, squeeze the handle, and spray at the base of the flame.) Write down where they are:
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 fire extinguishers. (If you have to use it remember to pull the pin, squeeze the handle, and spray at the base of the flame.) Write down where they are:
- Near the door,and near the fire exit at the back.
2. If you can, look up Fuel Pressure specifications for the vehicle you are testing. If
you can’t look them up, make a guess at the fuel specs you should have and write
them down here:
- 38-44 psi
Use eye protection. Optional: Relieve fuel pressure before installing pressure
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. Attach fuel pressure gauge and notice which scale on the gauge you will be using.
Briefly turn key on or start vehicle, then turn it off. Check for fuel leaks.
Are there leaks?
- NO there is not.
Measure the fuel pressure with the key on, engine off.
Record it here: .265 (also record the units you are using, psi, bar,
Kpa, etc…) .KPA.
Idling: Measure the fuel pressure with the engine idling. Watch the pressure for a
couple of minutes.
Record pressure here: .39Psi.
7. Maximum: With the engine idling, use the special tool to clamp the fuel return line.
Note: this can only be done for a short period.
Record pressure here:Off the clock top end
WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel
pressure regulator.
Record pressure here: .42 psi..
9. Residual: Turn off the engine, and watch the fuel pressure for five minutes.
Record your residual or rest pressure here: .43Psi
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 maybe ½ liter in 15 seconds)....The flow result i got from this engine was 0.5L in 15 seconds.
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 maybe ½ liter in 15 seconds)....The flow result i got from this engine was 0.5L in 15 seconds.
- This system is contently putting out a certan amount of fuel pressure at all times , this pressure comes from the intake manifold, the air entering
- Blockage in the fuel line could cause resistant in the system. also could cause the engine to be running leaner, roufer, loss in power and struggling to accelerate (flat spots).
- Also this could happen the other way around. due to too much pressure on the fuel line the car could be running richer resulting in poor fuel economy..etc.
- this could happen because of the intake manifold.
- the flow pressure could be high because the pressure is pushing the fuel threw the line quickly , forcing the injectors to spray a uneven ratio of fuel in to the combustion chamber.
- Bad fuel pressure in the fuel line could cause the engine to have poor fuel economy, hard morning starts or even rough idling (at traffic lights, parking ..etc) could cause the car to stolle out at random times, and also could put out black smoke or resegw.
- Always check the fuel pressure , fuel line, fuel filter, leakes in the pressure pumps.. etc.
