Fuel loses prime

HilendarHilendar Member Posts: 1
edited May 2019 in Buick
Have replaced fuel pump and have had tank cleaned. When first starting up, will run fine for a period of time, then engine cuts off from lack of fuel. Most times, can get it restarted with 20 min, keeping key on and trying to reprime. Occasionally it won't start at all. When it won't start at all, next morning it starts like it never had an issue. Have been dealing with this for two years and it's gone way past annoying.


  • imidazol97imidazol97 Member Posts: 27,103
    ??How long does it run after a cold start before it cuts off? Is this time about the same if it's restarted after having been driven a while?

    ??Does it cut off every time it's started? How does it die? Quick like key turned off and the tach drops to zero immediately indicating no spark signal? OR does it die kind of missing or acting like it's flooding out with a few burps before it dies?

    ??When you say it starts "with 20 min.," do you mean it will restart after 20 minutes of sitting and cooling?

    Keeping the key "ON" does not prime the fuel system. Turning the key off and then back on runs the key only for about a second and a half. Then the fuel pump turns off. So to prime a system that loses pressure sitting over night, you turn the key OFF and back ON typically 3 times. If losing prime due to a leaking injector or a fuel pump that doesn't hold back pressure, that will have the system the way it normally would be when the key was turned on the first time.

    I assume you replaced the fuel filter when the pump and tank cleaning were done.

    You need to find which is missing when it won't start. Air, fuel, or spark.

    !) If you can smell fuel at the exhaust pipe after trying to crank and failing to get it started, that would indicate you are getting fuel at correct pressure maybe...

    2) You need to know if you are getting spark during the times it fails to start up after dying. That would require being able to take off a spark plug wire and put an old spark plug, lawn mower or any old plug on the end of the wire, and laying it on a metal part of the engine. Then you watch the spark while someone cranks the engine. It should be blue ideally.

    3) You can check the injectors for operating by listening close or touching one watching for the click when it opens and closes quickly. People also have used the little light bulbs for marker lights on the car with the two wire leads and connector those leads into the injector plug after taking it off the injector. A quick flash should occur if the injector is being fired by the computer grounding it.

    No spark _could_ be from the crankshaft position sensor. Some weakened and don't give a good signal to the Spark Control Module when the engine gets hot. Let it cool and it works again. Some people used a cold cup of water over the sensor behind the harmonic balancer edge, which cools it quickly and gives a quick restart. A good empirical test.

    you need to find which is missing when it won't start.

    2014 Malibu 2LT, 2015 Cruze 2LT,

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