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If an engine doesn't have fuel, it won't run. Modern vehicles use a pressurized fuel system to deliver fuel to the fuel injectors. If there is a failure of this system, your engine won't start. I can't cover every manufacturer here, but I will cover the basics of how to check for fuel if you have a no-start condition.

The first thing to check for is fuel pressure. You can actually do this quickly on many systems. When you turn the key to the ON position, the fuel pump should run for about three to five seconds and then shut off. You need to know this for your testing so you don't get fooled into thinking the fuel pump should run all the time with the key in the ON position. If the computer doesn't see a crank signal after the ignition is turned on for three to five seconds, it turns the fuel pump off. During this time, fuel pressure should build up in the system and remain for some time after the fuel pump is shut off. The information about the crank sensor can be helpful here. If you have a start/die scenario, you might want to check the operation of the crank sensor. If the computer doesn’t see a crank signal it shuts off the fuel pump. If the fuel pump turns off, your engine won’t run.

Some engines have a Schrader valve in the fuel rail that you can depress to check for fuel pressure. Mind you, this is a quick check for fuel pressure and should not be taken as anything other than a verification that there is some pressure in the system, although it might not be enough to run the engine. Some engines won't start unless they have an exact fuel pressure; if it's low by just a couple PSI, the engine won't start. So by no means should you consider this test anything other than a verification that the fuel pump can or can not turn on and move fuel. If you don't see any fuel spray at all when you open the fuel system, then you can start looking into the fuel pump circuit to see what the issue is. Here's a video illustrating what I'm talking about using a Honda vehicle that does not have a Schrader valve on the fuel rail.

For checking the fuel pump circuit, first start by checking the fuel pump fuse. Fuses are often overlooked and they shouldn't be, as they are probably the most common cause of electrical faults. Next, there is likely a relay that controls fuel pump operation that should also be checked. Instead of going into lengthy explanations of how to do this stuff, this video explains the process.