How to Test Fuel Pressure and Flow

Being able to test fuel pressure and flow is critical when diagnosing a fuel system problem. This video goes over the proper way to test fuel pressure, and a way to test fuel flow without a flow meter.

Hello and welcome to Delphi’s how-to video series. I’m Clay, the senior product specialist here at Delphi Product and Service Solutions.

In this next video, we’re going to talk about fuel pressure and flow testing. Fuel under pressure can cause fire and injuries, so keep safety first. Wear your safety glasses and gloves. Keep away from open flames and no smoking.

Okay, so now let’s go ahead and perform our fuel operational test. Okay, so now we’re going to go ahead and check our fuel pressure and flow. First, we’re going to do the fuel pressure. So I’ve installed a fuel pressure gauge, and then we’re going to start the car and check the fuel pressure. So I’m going to have my assistant start the car. Go ahead Jeff, start the car up. So you can see here we’ve got good pressure. We’ve got about 60 PSI on this 2009 Impala. That’s a good pressure. So we’re good with that. So now we’ll move on to flow testing. Okay Jeff turn it off.

So the most accurate way of measuring flow is with a flow meter, but some shops may have that, but you may not. So we’re going to show you a pretty accurate way of doing that using a graduated cylinder. Now, what we’re going to do is we’re going to check the flow on this thing. We’re going to call it time fuel test. It’s going to check the amount of fuel we’re going to get out of this vehicle in a matter of five seconds. So I’ll go ahead and do that now. One, two, three, four, five. Okay, Jeff, go ahead and shut it off.

So make sure you use the appropriate container. We’re using glass here because plastic can fog up with gasoline. So we got about a hundred milliliters in this five second test. We’ll convert that to gallons per hour and compare it to a manufacturer specifications. So that’s pressure and flow testing. Thanks for watching. Be sure to check out our other Delphi How-To series videos to help save you time in your shop every day.