Chevrolet Fuel Pump Failures Explained

GM flat fuel pump connector

Chevrolet fuel pump failures are a common and growing problem. If you have a fuel pump harness connector that looks like the flat one on the right or the square one at the bottom, then consider replacing it when replacing the pump.

More details about this are below, but you might want to download your Chevy manual to help.

The defective Chevy fuel pumps can cause a stalling condition or a no start situation that can leave you stranded.

It started on Chevrolet truck models from 1996 to 2003 model years, but has expanded to other models as the connector and pump assemblies are not aging well. In fact, I have a financially strapped friend with an 04 Silverado that now caries a heavy rubber mallet in the truck.

When the fuel pump won’t run he pounds the under side of the fuel tank where the pump is mounted with the key on and it starts running.

I do not recommend that you do this I’m just sharing a story. You can go on many automotive forums and see people discussing this issue. Replacement of the fuel pump is not a quick or easy job.

This is because the pump is tank mounted and the fuel pump is replaced as a unit. The less gas in the tank the easier it is to deal with. The replacement parts for the job are also not inexpensive. To make matters worse, what I have seen are repeat failures of the replacement unit. It’s happened to me more then once and I’ve read about it on auto repair forums.

Causes of Fuel Pump Failure

The original Chevy pump motor has a life expectancy of about 15-20 years. Running the vehicle out of fuel, which will actually run the pump in a dry state can shorten the expected life span.

Gasoline is a petroleum product and lubricates the inside of the fuel pump, impeller and other moving parts. In addition, debris and sediment collects in the bottom of the tank and that stuff can damage the delicate internal workings as well.

Even if the pump doesn’t quit after running it dry, it could suffer a considerable reduction in operating pressure. Nevertheless, the more you run the vehicle low on fuel or out of fuel the more damage will occur internally and the quicker the pump will fail.

When you buy the replacement parts from Delco, which is what I do for my customers and also recommend to driveway mechanics, they will sell you a complete tank module. This factory replacement unit also includes the fuel level gauge sender, hanger assembly and tank filter sometimes called the sock.

Chevy Fuel Pump Kit

Some aftermarket replacement pumps just include the motor. This means you replace the motor and transfer the used fuel pump sock, fuel sending unit, and hanger assembly.

This process leaves more room for error and is also a large cause of repeat failures. I have experienced repeat failures even when using the most expensive replacement Delco parts.

I found a factory service bulletin that sheds some light on why it happens and what you can do to solve the problem. I made a short video that reviews the technical bulletin and outlines a few steps you can take to reduce repeat failures.

Fuel Pump Service Bulletins

The technical service bulletin that explains the cause of the repeat failure of the Chevy fuel pump replacement unit covers all years from 1996 to 2003 and includes all of the pickup trucks.

Also included is the Tahoe and suburban and their GMC counterparts such as the Sierra and Envoy. Oh and don’t forget the Cadillac Escalade is also included.

The Chevrolet service bulletin states that the cause of the repeat failures is due to worn or damaged electrical connectors at the fuel pump assembly. When you get the Delco replacement parts it comes with a new connector on the fuel pump side.

The problem is the connector on the vehicle side of the harness. In the online Chevrolet repair manual I use, a Tech Tip states, the connector should be replaced with the fuel pump assembly.

Since I first wrote this article the problem has expanded to the point a repair kit is now available. The Fuel pump harness connector pigtail repair kit comes with heat shrink connectors to protect the repair area.

This is fifteen dollars well spent. Failure to replace the electrical connector on the harness side can cause voltage spikes across the new fuel pump. Over time this can damage the part.

Replacement of the harness connector is a fairly simple operation and the parts are readily available from your GM dealer parts department. With the cost and difficulty of the repair it’s wise to follow the technical service bulletin.

Take a few extra minutes and replace the connector. In my own personal experience I’ve had no comebacks since using the new procedure. Give this fuel pump repair page a bookmark or share with a friend. Then visit the fix cars blog for more auto repair information.

Square GM Fuel Pump Connector

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