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Amedee, Former ASE Master Tech
Category: Car
Satisfied Customers: 26026
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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2000 Chevrolet Silverado 1500: V8..pickup..truck starts..the gas pedal

Resolved Question:

I own a 2000 Chevrolet Silverado 1500 4WD 5.3 Liter V8 pickup. The truck starts up fine when it is cold, but when I go to restart it up 20 minutes later it will not turn over until the 2nd or 3rd try and will have to tap the gas pedal to help it. Any clues to what is wrong and how I can fix it?


Buffalo, NY
Submitted: 10 years ago.
Category: Car
Expert:  Amedee replied 10 years ago.
Greetings! U could have a bad fuel pump. I would rec to check fuel pressure. Fuel injected cars are very fuel pressure sensitive. Fuel pressure is very important and must be within specifications! But if the pressure is low, it does not mean the pump is bad. A plugged fuel filter, a pinched line, and low voltage at the pump can contribute to low fuel pressure. All three must be check before replacing the pump!
Customer: replied 10 years ago.
Reply to amedee's Post: How can I check the fuel pressure and if I can check it myself what tools will I need? If I cannot what would you say the estimated costs of repair?

Thanks for your help!

Expert:  Amedee replied 10 years ago.

You will need a fuel pressure gauge. U can get one fro cheap at a local auto parts store.

When you turn ON the ignition switch, the Powertrain Control Module (PCM) turns ON the in-tank fuel pump. The in-tank fuel pump remains ON as long as the engine is cranking or running and the PCM receives reference pulses. If there are no reference pulses, the PCM turns the in-tank fuel pump OFF 2 seconds after the ignition switch is turned ON or 2 seconds after the engine stops running.

The electric fuel pump attaches to the fuel sender assembly inside the fuel tank. The in-tank fuel pump supplies fuel through an in-pipe fuel filter to the fuel rail assembly. The fuel pump provides fuel at a pressure above the pressure needed by the fuel injectors. A fuel pressure regulator, attached to the fuel rail, keeps the fuel available to the fuel injectors at a regulated pressure. Unused fuel returns to the fuel tank by a separate fuel return pipe.

The numbers below refer to the step numbers on the diagnostic table.

  1. When the ignition switch is ON and the fuel pump is running, the fuel pressure indicated by the fuel pressure gauge should read 379-427 kPa (55-62 psi) . The spring pressure inside the fuel pressure regulator controls the fuel pressure.
  2. A fuel system that drops more than 34 kPa (5 psi) in 10 minutes has a leak in one or more of the following areas:
    • The fuel pump check valve
    • The fuel pump flex pipe
    • The valve or valve seat within the fuel pressure regulator
    • The fuel injectors
  1. A fuel system that drops more than 14 kPa (2 psi) in 10 minute after being relieved to 69 kPa (10 psi) indicates a leaking fuel pump check valve.
  2. Fuel pressure that drops-off during acceleration, cruise, or hard cornering may cause a lean condition. A lean condition can cause a loss of power, surging, or misfire. You can diagnose a lean condition using a scan tool. It an extremely lean condition occurs, the heated oxygen sensors will stop toggling. The heated oxygen sensor output voltages will drop below 300 mV . The fuel injector pulse width will increase. IMPORTANT: Make sure the fuel system is not operating in the Fuel Cut-Off Mode. This can cause false indications by the scan tool.
  1. When the engine is at idle, the manifold pressure is low. This low pressure is applied to the fuel pressure regulator diaphragm. The low pressure will offset the pressure being applied to the fuel pressure regulator diaphragm by the spring inside the fuel pressure regulator. When this happens, the result is lower fuel pressure. The fuel pressure at idle will vary slightly as the barometric pressure changes, but the fuel pressure at idle should always be less than the fuel pressure noted in step 2 with the engine OFF.
  1. A rich condition may result from the fuel pressure being above 427 kPa (62 psi) . A rich condition may cause DTC P0132, DTC P0152, DTC P0172 or DTC P0175 to set. Driveability conditions associated with rich conditions can include hard starting followed by black smoke and a strong sulfur smell in the exhaust.
  2. This test determines if the high fuel pressure is due to a restricted fuel return pipe, or if the high fuel pressure is due to a faulty fuel pressure regulator.

Its hard to say the cost. Every shop is different. Be sure to shop around!

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