Initial Startup

  • 1 POST
  • V6
  • FWD
  • 86,000 MILES

When I try to start my car on a cold engine, it takes a few seconds to turn over. After initial use, it starts right up. It is a significant difference compared to other cars. I just want to know if it could pose a problem in the future. Even a buddy of mine thought I used up the battery when he tried to start it.

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have the same problem?
Sunday, May 14th, 2017 AT 1:43 PM

1 Reply

  • 29,780 POSTS

Long crank time, then running okay is generally a sign that fuel pressure bled down while the engine was off for a long period of time. That is usually caused by a leaking injector, but a leaking pressure regulator, or a leaking check valve in the fuel pump can cause that too. The most serious outcome, which is still not terribly significant, is that raw fuel leaking into that cylinder can run down past the piston rings and wash the film of oil off the cylinder wall. That will accelerate wear during the first few seconds after start-up. After that, the fuel in the oil will vaporize and be pulled out to be burned in the engine. The worst thing you can do related to that is mostly short trips where the engine never reaches normal operating temperature.

The sure way to verify my diagnosis is to connect a fuel pressure gauge to the test port and see if the pressure has dropped after a few hours. It should hold for days, if not weeks. If the pressure has dropped significantly, it needs to come up to a certain pressure before the engine will run, and the engine needs to be rotating, (cranking or running), for the fuel pump to run. Add to that battery voltage gets drawn down a lot by the starter, and that means the fuel pump is also running on low voltage, so it takes even longer to build pressure.

A second thing you can do to prove to yourself how smart I am is to turn on the ignition switch without cranking the engine. After a couple of seconds, turn it off, wait a few seconds, then turn it on again. Maybe even do that a third time, then crank the engine. Besides the fuel pump running when the engine is rotating, it also runs for one second when the ignition switch is turned on, also to insure pressure is up for starting. Turning the ignition switch on multiple times before cranking the engine should make the fuel pump run multiple times, and that will get the pressure up faster.

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Sunday, May 14th, 2017 AT 4:21 PM

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