truck wont stay running

[Sanddraggin]

I have a 2000 Chevy silver ado Z71 with a 5.3 motor & 4wd, 102,000. and it lossed all power driving down the road, if you stepped on the gas it would not do anything, just spit and sputter, and eventually quit, it would start back up but you could not step on gas or it would stall, eventully would not start at all. after sitting awhile it would start up but would eventully stall (30 seconds or), am getting no warning lights or any indacation from the dash what could be wrong. I think it might be a clog fuel filter or even a bad fuel pump, does any body have any ideas to help! how do you figure out if it is the fuel pump. fuel pump is in the tank on my truck by the way! thanks, need help please!!

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[aja72]

I think you need to check it your truck's fuel pump. This type of problems is created due to the fuel pump problem. I suggest you to check fuel pump properly and if any problem on pump you need to change that pump.

[Sanddraggin]

any idea how to check the fuel pump on this vehicle?

[rmck490]

I'm new to this forum and ran accross your post and thought I might be able to help if you haven't figured it out already. I have the same year and model truck and have spent time under the hood. I have my own issues I'm researching.

Your problem sounds like it may be an intermittent problem which means either the fuel pump is going bad, your fuel filter is plugged (or partially plugged), you may have an open electrical problem in the circuit, the fuel pump relay is bad, or your PCM could be the problem. I've read that sometimes the electrical pigtail connectors at the tank go bad and need replacing as well.

A simple test for the fuel pump would be to turn the ignition on (engine off-don't start) and listen for the fuel pump running in the tank. The pump will pressurize the system for about 2 seconds. If you don't hear it or if it continues to run without stopping, you definitely have something bad going on. Continuously running is probably a leak in the fuel system somewhere. Not running at all could be the pump, PCM, the pigtail, an open circuit, or relay problem. You should be able to hear it run everytime you turn the iginition on and the fuel system has been allowed to relieve pressure naturally.

To properly test for fuel pressure, you need a fuel pressure test gauge. It can be attached to a port on the engine's right bank fuel rail feed line. This port has a black cap covering the port. If you don't have a fuel pressure test guage, you can buy one at most parts stores or find a mechanic buddy who may have one you could borrow. The test guage will have a pressure relief button and a long tube to drain fuel into a container. The process will dump fuel and thus fumes will be present. Take caution to keep ignition sources out of the area (doing it outside is best).


To test for fuel pressure:

1. Relieve the fuel pressure from the system:
   1. Disconnecting the negative (-) teminal on the battery.
      1. You may need to complete a engine idle relearn procedure later.
      2. Also, if you have a factory radio, make sure you know the theft code you programmed or turn the anti-theft feature off or your radio may not work later.
   2. Connect the test guage to the fuel pressure test port.
   3. Put the drain hose on the test guage into a small container and press the relief button on the guage.
2. Reconnect the negative battery terminal.
3. Turn the iginition on for 10 seconds to pressurize the system (a buddy helps). Do not start the engine.
4. Turn the iginition off and relieve the pressure again.
5. Turn the ignition on for 10 to 20 seconds to and then off again. Do this twice but leave the ignition on the second time. You maximize the pressure reading this way.
6. The fuel pressure should read between 55 and 62 psi on the guage and should drop about 5 psi in the next 10 seconds or so.
   1. If you're not within the specified limits (55-62 psi), your pump or fuel filter is probably bad.
   2. If you are within the limits and the pressure drops more than 5 psi, you have fuel leak somewhere in the system. Possibilities are:
      1. Bad fuel pump.
      2. Bad fuel injectors
      3. Bad fuel injector or fuel rail seals (you should be able to smell fuel or see fuel on top of the engine if this were so)
      4. Leaking fuel line (you would smell fuel or see puddles of fuel under the vehicle)
      5. Bad fuel pressure relief valve

I would recommend you do a more comprehensive diagnosis beyond these simple checks. You may run these tests and decide to replace the pump, the problem still exists, and only to find later that it was simply the fuel pump relay or fuel filter that was bad or you have to replace the PCM as well.

If you have to replace the fuel pump, it would cost you between $125 to $400, depending on where you buy it, for the entire in-tank assembly. You can't just replace the fuel pump. It is attached to the fuel level assembly which comes as an entire unit. I recommend that you remove the truck bed (or move it aft resting on the wheels) to access the top of the tank. You avoid having to remove fuel and the laborious task of removing the tank to deal with. You'll need help doing this though.

There are other resources out there for a subscription fee or free advice on the internet to help with more diagnosis if you choose. Or, take it to a mechanic.

This may be more than you asked for but I thought you might want to know what you may be in for and all of the possibilities. If you don't get it right the first time, you could spend more money than necessary. My bet is that it's probably the fuel pump. I hope this helps and good luck.

Bob

[Pinvaph09]

I dont think that truck even has linkage. I think its like fly-by-wire. Ill check on mine once I get a chance. This may be a dumb question, but you are pressing the brake pedal when trying to shift it right?

[needshave]

I have almost the same problem. 2002 silverado, 4.3l. Started poorly ran about 500 ft and died. Started it again and went about 200 ft and never started again. Had to have it towed back up my long driveway to the back of the garage.
Yesterday I pulled the old fuel filter out to replace it, Possible problem. Not so, the filter appeared fine. I turned the ignition on, was getting what appeared to be plenty of fuel being dumped from the line. Replaced the filter, no change. I sprayed starting fuel down the throttle body throat to see if it would fire, it did. So it appears to be a fuel delivery problem. Although I can hear the fuel pump run and see plenty of fuel pumped, I'm told the only way to be sure it's the pump or not the pump is to take a pressure reading at the fuel rails. Autozone has available a test system you can lay down $160.00 for and test the system, return it and get all of the deposit back. 160 seems to a bit much for what it is, but as long as you get all back.........I guess that's o.k. It 12 degrees here in Ohio this morning and I preparing to go outside to work on this thing. I will post my findings here in about a hour as soon as the finger thaw. OH, BY THE WAY......i'M ALMOST SURE IT'S THE PUMP BUT WHO HAS SOME RECOMMENDATIONS ABOUT REMOVING THE PUMP. Removing bed vs. dropping the tank. As murphys law would require the tank is almost full and I'm working by myself! ANy recommendations would be appreciated.

[needshave]

I was able to pry my cramped frozen fingers from the fuel rails of the 4.3 to get back in. Autozone's test kit has a 90 degree adapter fitting to the schrader fitting on the fuel rail which is most difficult to get installed on the schrader. It line up perfectly with the 10 gauge bracket they have on the manifold to support a wire harness.
With the key on, the fuel pressure measured was 20 PSI. That way low from where it should be. (60 PSI) But, this I don't understand. I have measured it several times to make sure there is no air in the line from where I installed the fuel filter. I always get 20 psi................when I turn the key on, I can hear the fuel pump run and shut off. I get 20 psi. If I leave the key on, measure the pressure, then bleed off the pressure at the gauge(remember the key is still on) it will drop back to zero and the pump never kicks back on. Why is that? I would think that although it's output pressure is low, it would kick back on and attempt to reach pressure. Any one have any thoughts??? Your thoughts appreciated.

[tasutt2009]

may also be a faulted cam sensor.

[Evepherry]

89silverado: Yup its gettin air. Air cleaner is off of the air duct.Anyone know if I can put the computer from my wifes 99 Tahoe 4X4 5.7 in my truck as as to see if its the computer and not screw up her computer by doing so?