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:
Front left of the room
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:
38-44psi
3. 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? Yes ...................... No ✓
If there are leaks you must correct them and retest before continuing.
If there are leaks you must correct them and retest before continuing.
5. Measure the fuel pressure with the key on, engine off.
Record it here: 40psi
6. Idling: Measure the fuel pressure with the engine idling. Watch the pressure for a couple of minutes.
Record pressure here: 41psi
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: 75psi
8. WOT: With the engine idling, disconnect and plug the vacuum line going to the fuel pressure regulator.
Record pressure here: 48psi
9. Residual: Turn off the engine, and watch the fuel pressure for five minutes.
Record your residual or rest pressure here: 42.5psi
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 ½ liter in 15 seconds)
666ml
11. 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: ✓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?
To make sure it is running at its maximum capacity
13. Describe the symptoms a vehicle would give with each case
Low fuel pressure
It will run lean , it wont idle properly. RPM will be low and it will be running rough
Low fuel flow
Blocked fuel filter , weak return vavle in pump , sping cam gets weaker it will always be richer , which means it will use alot of fuel
High fuel pressure
Too much fuel being used , dripping injectors means that there will be flooding , return regulator will be broken.
Faulty fuel pressure regulator
Floading of injectors which will leak out. The injectors causes hard starting , poor economy and useing more fuel
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