These symptoms point to a leaking injector. Fuel pressure should hold for weeks when the engine is off, but a leaking injector will let it bleed down within a few minutes. When you turn the ignition switch on, you may be able to hear the hum of the fuel pump running for one second. That is to insure pressure is up for starting in case it leaked down a little, but not all the way to 0 psi. When the pressure is at 0 psi, one second is not enough time to build the pressure to where it needs to be. The pump resumes running during cranking, but at that time, battery voltage is drawn down to around ten volts by the starter. That lower voltage slows the fuel pump down, so it takes a lot longer to build fuel pressure. That is where the five to ten second crank time comes from.
The correct way to verify this is to connect a fuel pressure gauge and watch what the fuel pressure drops to and how long that takes. If an injector is leaking, you will smell the unburned fuel at the tail pipe. If you can smell the fuel before starting the engine, and especially when sticking your nose under the hood, a better suspect is a leaking O-ring between an injector and the fuel rail. You may see the wetness around an injector too. Typically those O-rings stop leaking when they get warm.
You can usually get the engine to start easier by getting the fuel pressure up higher before you crank the engine. Turn the ignition switch to the "run" position, wait for a few seconds, turn it off and wait a few seconds, then turn it back on and crank the engine. That will let the fuel pump run twice as long at full battery voltage to get the pressure up. If that works, it is not a solution. It is just a clue to the diagnosis.
Dec 8, 2017 at 1:33 PM
