Loss of power, codes 0131 and 0151

[Erich777]

GPRacer, your saying your Fuel Pump gave you this behavior just before it failed?

 

[gpracer1]

GPRacer, your saying your Fuel Pump gave you this behavior just before it failed?

It failed in my dad's garage. I smacked on the bottom of the tank with a shovel with the key on and got it going....so I could take it to my house and replace it.

Half way there, it started to sputter in traffic, I would push the gas pedal and it would have no power but would run. This lasted for about 1 minute, then it died for good.

 

[Erich777]

Fuel Pressure:

In the driveway standing on the brakes.
http://www.youtube.com/watch?v=x7Z7DhyZs4k

Running down the road, it bounces all over the place.
http://www.youtube.com/watch?v=UobpV4rJBow

 

[gpracer1]

I would have to guess that is a pressure regulator going out. The pump wont be able to make the needle swing back and forth that quick.

 

[SunlitComet]

Based on your gauge readings I suggest you follow step #27 in the chart below.

 

[SunlitComet]

Your Vehicle: 1999 Chevy Truck K Tahoe 4WD V8-5.7L VIN R
Notes Testing and Inspection

Circuit Description
When the ignition switch is turned ON, the Vehicle Control Module (VCM) energizes the fuel pump relay which powers the in-tank fuel pump ON. The pump remains ON as long as the engine is cranking or running and the VCM is receiving reference pulses. If there are no reference pulses, the VCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops. The VCM will also turn ON the fuel pump for 2 seconds when the ignition is turned to the OFF position.

An Electric Fuel Pump pumps the fuel through an in-line filter to the Central SFI unit. The pump is attached to the fuel level meter assembly inside of the fuel tank. The pump is designed to provide fuel pressure above what is needed by the fuel injectors. The pressure regulator keeps the fuel available to the injectors at a regulated pressure. Unused fuel is returned to the fuel tank by the fuel return pipe.

Diagnostic Aids

Tools Required

• J 34730-1A Fuel Pressure Gauge with J 34730-250 Fuel Pressure Adapter Kit.
• J 42873-1 and the J 42873-2.

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

1. Wrap a shop towel around the fuel pressure connection to absorb any small amount of fuel leakage that may occur when installing the fuel pressure gauge. Turn ON the ignition leaving the engine OFF, the fuel pressure should be 415-455 kPa (60-66 psi) when the pump is running. This pressure is controlled by a spring pressure within the regulator assembly.

1. The fuel pressure that continues to fall is caused by one of the following items:

• • The in-tank modular fuel sender is not holding pressure.
  • The fuel pressure regulator valve is leaking.
  • A Central SFI injector is leaking.
  • Fuel line is leaking.

1. If the fuel pressure is less than 379 kPa (55 psi) at idle, it fails into the following 3 areas:

• • The pressure is regulated but less than 379 kPa (55 psi).The amount of fuel reaching the injector is sufficient, but the pressure is too low. The system will run lean, hard starting cold, no start, overall poor performance, and may set a DTC. Refer to Engine Cranks but Does Not Run. http://www.alldatadiy.com/alldata/A...34853741/34857029/34857030/34857663/122923019
  • A restricted flow causing pressure drop - Normally, a vehicle with a fuel pressure of less than 300 kPa (44 psi) at idle is inoperable. However, if the pressure drop occurs only while driving, the engine will normally surge then stop running as the pressure begins to drop rapidly. This is most likely caused by a restricted fuel line or plugged filter.
  • A leaking or contaminated pressure regulator valve or seat interface may not allow the regulated pressure to be achieved.

Notice: Do not allow the fuel pressure to exceed 517 kPa (75 psi). Excessive pressure may damage the fuel pressure regulator.

1. Restricting the fuel return line allows the fuel pressure to build above regulated pressure. With the fuel pump commanded ON, the fuel pressure should rise above 455 kPa (66 psi), as the valve in the return line is partially closed.

1. When the engine is idling, the manifold pressure is low (high vacuum) and is applied to the fuel pressure regulator diaphragm. This will offset the spring and result in a lower fuel pressure. This idle pressure will vary somewhat depending on the barometric pressure; however, the pressure at idle should be less indicating the pressure regulator control.

1. If the injector(s) is not grounded, physically remove suspect injector(s) and inspect for a fuel leak while system is pressurized. If the fuel injector(s) are not leaking and fuel pressure is not holding, the fuel pressure regulator should be inspected for a slow diaphragm leak.

 

[Erich777]

This is really weird,
every time I reload this page, I get different pages of sunlit's pdf's! Fortunately I downloaded them the first time, but right now it looks like transfer case mounting bolts and wiper motor diagrams.

 

[SunlitComet]

The images locations rotation I can not stop. the are directly from the content provider and it is something they do. It is faster to post them this way then making pdf's all day long. If you ever want it re-posted again let me know it is easy to do just like I did it above just now.

 

[Erich777]

So, just where IS the fuel pressure regulator? Do I have to remove the top of the intake manifold to get to it? Or can the assembly come out somehow?

 

[arb905]

If you have the spider assembly fuel injection system, it is located under the plastic intake half. The fuel lines should run up the driver side and the regulator is under there. I have been told if the regulator is bad, it will dump fuel and give misfire codes to cylinders 5 & 6. I you have to replace the regulator just replace the whole assembly with the MFI conversion. Good luck.