Why is my GM fuel pump going bad?

In this tutorial I’m going to show you two different methods to verify if the no start condition on your 4.3L, 5.0L, or 5.7L throttle body fuel injection (TBI) GM vehicle is due to a lack of fuel, which usually means that the fuel pump has gone bad. One method involves using just starting fluid and the other involves using a fuel pressure gauge.

What causes a bad gas gauge on a Chevy truck?

A poor ground or loose connection to a gas gauge is just as likely to cause problems as loose or dirty battery cables assuredly will with your starting system.

How to check no fuel condition on GM 4.3L?

I’ve also included how to check a no fuel condition with starting fluid (although this is not the most effective way to test the fuel pump). It’s been my experience that misdiagnosing a bad fuel pump is a common occurrence on the 4.3L, 5.0L, 5.7L GM vehicles with the ‘Spider’ fuel injector assembly.

Can you test the fuel pump on a GM Truck?

And although GM did not include a Schrader valve to which you could connect a fuel pressure gauge, it can be tested with one to find out if the fuel pump is producing the correct pressure (or not).

Why is the fuel gauge on my Chevy truck not working?

The most common problem with the fuel gauge reported by Chevy truck owners is a complete failure to register the fuel level. The fuel gauge sits on empty, even after you’ve just filled up the tank.

When to know if your GMC Sierra fuel pump is bad?

If your car isn’t starting at all, and you hear the fuel pump prime that is usually a good indication that the pump is working to some capacity. Testing your Sierra’s fuel pressure on each side of the pump would be the best way to diagnose this problem.

What are the symptoms of a bad fuel pump?

Also, the symptoms are almost exactly the same as bad/clogged fuel filter. Here are the most common symptoms of a bad fuel pump in your GMC Sierra: One of the most common signs that a fuel pump is going bad is a whining sound. The whining sound can indicate that the fuel pump is going out before there are any performance based issues.

What causes a fuel injector to go bad?

The most common type of failure (related to the ‘Spider’ fuel injector) is usually not the assembly itself going bad, but the fuel pressure regulator going bad. The fuel pressure regulator is infamous for leaking fuel from its vacuum inlet nipple.

Where is the fuel pump on a GM Truck?

As you’re already aware, the throttle body fuel injection system on your 1987 to 1995 4.3L, 5.0L, or 5.7L pickup (or SUV) uses a low pressure (12 PSI) electric fuel pump located in the gas tank. And although GM did not include a Schrader valve to which you could connect a fuel pressure gauge, it can be tested with one to find out if the fuel …

How can I check the pressure of my fuel pump?

There are two ways to tap into the fuel line to see how much pressure the fuel pump in producing. One method involves removing the fuel filter and using an adapter, that has a Schrader valve on it, in its place. You then connect your fuel pressure test gauge to this adapter.

How does the fuel pump work in a car?

The fuel pump receives the fuel from the fuel tank and throws it into the fuel rail which transfers the liquid into the cylinders using the knowledge of the fuel pressure sensors. Naturally, if the pressure is not according to the manufacturer’s recommendations, you will experience little to no response from the car’s engine.

Can a bad fuel pump start a GM Spider?

If you need to test the ‘spider’ equipped GM pickups or SUVs, the following tutorial will help: Troubleshooting The Fuel Pump (GM 4.3L, 5.0L, 5.7L). A bad fuel pump will make your 4.3L, 5.0L, or 5.7L throttle body fuel injected pickup or SUV crank but not start. Here are some more specific symptoms:

Why does my GMC engine start but not run?

Repair guides and support for cars, trucks, and SUVs manufactured by GMC. Answered! View the answer I have this problem too Is this a good question? An engine will start but not run when the fuel runs out .

What to do if your Chevy Express won’t start?

It sounds like it’s trying to start but won’t. The key only comes out in vans that are equipped with the V.A.S.T system. Weirdly banging on the dash sometimes works too. If it does not try to start for a second and then die, replace the cap and rotor. This video is about an issue involving the disabling of the fuel pump for security. Loading…

What to do if your Camaro engine hesitates?

If the mechanic believes the problem is the fuel pump, he or she will remove the fuel tank if necessary to inspect the pump. If the pump has indeed failed, the mechanic will replace it. If the fuel tank itself it beginning to show signs of age, it may be convenient to change the pump and tank at the same time.

What happens when you run low on gas?

Running low on fuel can also cause the fuel pump to pick up sediments, which clog the fuel filter, fuel injectors, or high pressure fuel pump. If your gas gauge isn’t working, it’s important to identify the source of the issue, then make a plan for repair.

What should I do if my fuel pump is low?

The first thing you can do is to check the screen filter. The screen filter protects the fuel pump from dust and debris and can get clogged up pretty quickly. This can hinder the flow of fuel to the fuel pump and into the cylinders. So, it is better to clean the screen filter and replace it with a new one if needed.

Why is my GMC Sierra 1500 stalling out?

No change. Next, read somewhere that bad ground wire on Thermostat housing can cause ECM issues. Checked it, cleaned it off, verfied that contact wanhers are all steel and attract a magnet, reinstall the ground wire.

How does a GMC Sierra 1500 fuel pump work?

The older model has steel lines coming off of the top of the pump to the frame rail and then connects to the frame steel lines with short hoses, you’ll need line wrenches and the ability to curse. The newer style has plastic tubes from the plastic pump casing and uses those quick connect fuel fittings and you’ll need the disconnect tool.

What should the FPR be on a GM Truck?

If the system holds pressure then the fpr is ok. If you loose pressure then the fpr is allowing fuel to pass into the return line. In that case you have a bad fpr. 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 ps i).

What should the fuel pressure be on a GMC Sierra?

Drives:2004 GMC Sierra Posted October 8, 2010 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 ps i). The spring pressure inside the fuel pressure regulator controls the fuel pressure.

Can a fuel pump leak cause a P0300 to misfire?

Intake leak, injector and fpr leak can cause P0300 multiple misfire though. Idle will be unstable and rough. Injectors and fpr can be checked with upper intake off with fuel lines connected and fuel pump primed. Yes, must prime before starting to avoid hard start.

What does it mean when your fuel pump is losing pressure?

Losing Fuel Pressure. If the system keeps pressure you know that injectors are ok and the problem may be down stream (fuel pump or fpr). On the flip side, if it didn’t hold pressure then it could be an injector or an fpr leaking into the vacuum line. To check the fuel pump, presurize the fuel system and only block off only the return line.

How to check fuel pressure in Gen 5.7L?

1. Fuel pressure regulator- pull the vacuum tubing off the fpr and if there is fuel, diaphragm is shot, Replace the fpr. Oh I did not notice you have an old gen 5.7L. FPR is inside the intake. Can’t check the diaphragm condition unless intake is off. 2.

What should the fuel pressure be on a Chevy Cheyenne?

93 Chevy Cheyenne k3500, if it is running the Chevy vortec engine the fuel pump pressure is way too low, should be 56 psi+ depending on CSFI/CPI system or it will not start or open injectors, with out the aid of starting fluid. The factory manual specifies that the fuel pressure for the CSFI system should be between 56-62 PSI.

What are the most common problems with a GMC Sierra?

Another 258 people reported the second-biggest issue where heating and air conditioning temperature and air delivery mode door actuators may fail. If one or more delivery mode door actuators fail, the HVAC system may not produce correct temperatures or air delivery. The HVAC system stores fault codes, which help with diagnosis.

What kind of gas mileage does GMC Sierra 1500 get?

The Dynamic Fuel Management system allows for better fuel economy with the Sierra 1500 getting 17 mpg overall, and the diesel option topping off at 23 mpg.

How to check fuel pressure in a GMC Sierra 1500?

You will have to check the fuel pressure at the rail, the test port is ontop driverside about 3/4 the way back. Black cap on aluminum fuel line. The best thing would be to buy or rent a fuel pressure test gauge as it would thread onto this port. If not I’ve used good safety glasses a rag and a screwdriver to check for pressure.

Why does my GM 91 k1500 not start?

If it runs when he pours gas down the throttle body the ignition is fine. It is fuel related. You need three things to make an engine run. Spark, fuel, and compression. Every no start I did at the GM dealer i would take my can of carb cleaner and spray it in the throttle body and try to start the engine.

Why is my GM fuel pump going bad?