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engine replacement - converting back to gasoline only

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  • engine replacement - converting back to gasoline only

    I just replaced the engine on my 2000 cavalier due to some internal dammage and high miles. We put another used 2.2 in it, and I wanted to make it gasoline only (due to several failed cng components) so we left the cng components under the hood uninstalled(low pressure solenoid and low pressure regulator and fuel rail with bi-fuel injectors).

    Once the engine was replaced, we were unable to start the car. It appears as though no fuel is being supplied to the cylinders. We can actually start it briefly with by spraying starter spray into the intake. I wonder if the cng components especially the fuel rail and bi-fuel injectors have to remain intact to satisfy the computer Or if there are any compatibility issues between motors. The dealer told me the engine was compatible, but I don't know what year the replacement is. Can anyone provide any advise?

  • #2
    Re: engine replacement - converting back to gasoline only

    To clarify, I did not install the cng components from the bi-fuel engine that were previously fixed to the engine. This included the intake manifold, fuel rail with bi-fuel injectors, and the plate on top which has the low pressure solenoid and the regulator on it. The car turns over easy but does not fire. I am also questioning the re-wiring of the starter, which another person completed. There are several wires on the starter and a couple that i'm not sure about. The two i'm not certain of might be or have fusible links in them. One is light blue or green and the other is black and yellow. Does anyone know which wires go on which terminals? Or can someone send me a picture or diagram of their wired starter? Thanks.


    • #3
      Re: engine replacement - converting back to gasoline only

      There are no "bi-fuel" injectors in a 2000 Cavalier. The injectors in the intake manifold are for gasoline operation only and are required for the car to operate on gasoline. Your car (as were all Cavaliers of this vintage) were involved in a recall that requires the addition of a slave relay between the starter and the ignition switch. This recall is most likely the source of the extra wires. You can remove the regulator,GMS/MCV, and LPL valve assembly. The distribution adapter can be removed and replaced with a hose from a standard Cavalier. The tank, HPR, and fuel fill and discharge lines can be removed. The coolant lines at the heater can be replaced with non-CNG hoses and then the stainless lines to the rear of the car can be removed. The wiring from the tank to the front of the car can be removed. The AF ECU can be removed and the two connectors filled with silicone. The parts removed, if sold on E-Bay will easily cover the cost of your engine.