At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Here are the usual suspects:
stuck fuel valve/float valve in the carburetor.
clogged fuel filter. or fuel line.
defective fuel pump.
electric fuel pump may be just a blown fuse, or wiring problem. good hunting.
Just because it pumps gas doesn't mean it is at the exact pressure it should be? Most fuel pumps have a psi of 40 to 45 psi, your fuel pump could be pumping at 25 psi or less which is not enough to start your car even though you can see some fuel pumping out. A simple tool to check fuel pressure can be bought at any auto parts store, check the specs on the fuel pump for your 02 Chevy first to see at what pressure it works, then use the fuel pressure gauge to check it. Anything less than what the specs on your fuel pump are suppose to be and you have a bad fuel pump?
Let's say your fuel pump works at 43psi, you hook up the fuel pressure gauge and you find that it reads 25 to 30 psi, that means it's not enough fuel pressure to start your engine.
You should have a test port on the Fuel Supply rail, use a tool from a local auto parts "Tool Loaner program" where you can borrow tools for free,w/a deposit of course,then follow the steps provided;
MPI Fuel System Pressure Test
The MPI fuel system used in vehicles equipped with a 4.OL engine employs a vacuum balanced pressure regulator. Fuel pressure should be approximately 55-69 kPa (8-10 psi) lower with the vacuum line attached to the regulator than with the vacuum line disconnected. System fuel should be 214 kPa (31 psi) with the vacuum line connected to the regulator and 269 kPa (39 psi) with the vacuum line disconnected. CAUTION: Some fuel may be discharged when connecting fuel gauge to fuel rail.
Connect a 0-414 kPa (0-60 psi) fuel pressure gauge to test port pressure fitting on fuel rail (Fig. 7).
Remove vacuum line from pressure regulator.
Start the vehicle.
Note gauge reading. With vacuum line disconnected, fuel pressure should be approximately 269 kPa (39 psi).
Connect vacuum line to pressure regulator. Note gauge reading. Fuel pressure should be approximately 214 kPa (31 psi).
If fuel pressure is not approximately 55-69 kPa (8-10 psi) higher with vacuum line removed from regulator, inspect pressure regulator vacuum line for leaks, kinks or blockage. CAUTION: Fuel pressure will rise to as much as 655 kPa (95 psi) when the fuel return tine is pinched shut, shut engine down immediately after pinching oft fuel return line.
If fuel pressure is low, momentarily pinch shut the hose section of the fuel return line. If fuel pressure remains low, inspect the fuel supply line, fuel filter, and fuel rail inlet for blockage. If fuel pressure rises replace fuel pressure regulator.
If fuel pressure is above specifications, inspect the fuel return line for kinks and blockage.
Capacity Test
Remove the cap from the pressure test port in the fuel rail.
Connect a 0-414 kPa (0-60 psi) fuel pressure gauge to the pressure fitting on the fuel rail (Fig. 7).
Start the vehicle. Pressure should be approxi- mately 214 kPa (31 psi) with the vacuum hose connected to the pressure regulator and 269 kPa (39 psi) with the vacuum hose removed from the pressure regulator.
If the pressure is not to specification, check the following before replacing the fuel pressure regulator:
4a - Inspect the fuel supply and return lines/hoses for kinks or restricting bends
4b - Check the fuel pump flow rate. A good fuel pump will deliver at least 1 liter of fuel per minute with the fuel return line pinched off. If the fuel pump does not pump adequately, then inspect the fuel system for a plugged fuel filter or fuel pump inlet filter (sock). Fuel pump flow rate can be done by connecting one end of an old A/C gauge hose to the fuel test port on the fuel rail and inserting the other end of the hose into a container of at least 1 liter capacity. Run the fuel pump by installing a jumper wire into diagnostic connector terminals D1-5 and D1-6. Be sure to pinch off the fuel return line or most of the fuel will be returned to the fuel tank.
FUEL PRESSURE
Command the fuel pump ON with a scan tool.Observe the fuel pressure gage with the fuel pump commanded ON.VIN Z335-375 (48-54 psi)Except VIN Z385-425 kPa (55-62 psi)
I am sorry to say that if the old pump was putting out 40psi then the pressure switch will need the same psi from the new pump. With the psi les then what the computer knows the engine needs it will not allow it to start and run.
check for 12v constant at your fuel pump if you are not getting that replace your relay.
if you are getting 12 volts at your fuel pump the fuel pump is possible to run tuel it gets warm then shut down to a lower rpm I would then replace the fuel pump
Fuel pump is bad. At idle pressure should read 50 PSI. Replace with original manufacture fuel pump after market pumps will burn out fast and are unreliable from my experience. Also could have a bad fuel regulator but that only works while driving down the road full throttle. You can unhook the fuel rail pressure regulator and that will give it full fuel and the pressure reading should read 60 PSI while it is running. If you turn the engine off and turn the key to run position it should read 50 PSI and hold for 60 seconds, if it drops below 30 PSI after 30 seconds Pump is defective. Many pumps are going bad here of late as people have been running them less than ¼ tank and this kills the pump. The fuel cools and lubricates the pump so the lower the fuel level the worse it is on the pump below ¼ tank. Not to hard of a job to do if you want instructions let me know.
×