Car does not start

My sister’s car is not starting.

From a completely off position if we try to start the car, the engine will turn over and the car will start but then immediately stop. If we start the car and press on the gas the engine will rev high right before it stops. If we do not completely turn off the car with the key afterwards and try to start the car again, the engine will turn over and sparks but will not start again.

If we turn the car completely off and then try to start it again, it will start and then turn immediately off again.

The spark plugs are sparking and we can hear the fuel pump turn on.

Morning of having the issue, my sister said that the car had a hard time turning over and so she had her battery tested which failed and so she purchased and installed a new battery. With the new battery came this issue. She has had her battery die before and has replaced it prior, so we don’t believe that there is any type of security installed that would be turning the car off.

Having this trouble start after the battery was changed does seem like it could be a security system issue.

It sounds to me that the fuel pump may be being shut down by the ECU. If this is so it may be the ECU doesn’t see the ignition pulses, even though they are there, and shuts down the pump. Bypassing the power to the pump temporarily to see if that makes the car run would check that idea out. The fuel pump relay may be another thing to look at.

Yeah agree. The thing to do is to hook up a test light at the fuel pump factory prime connector under the hood. Test light probe on connector and clip to ground. If there is power to the pump, the light will light. So if its the computer or relay, the light would go on durprior to cranking and then shut off, telling you either the relay or the computer is causing a problem (or the pump itself isn’t starting again reliably).

Ended up replacing the fuel filter and issue was resolved. My co-workers were excited it was such an easy fix but after doing some research I believe it was a security system shutting the engine down.

Before replacing the filter we relieved pressure on the line by removing the fuse that controlled the fuel pump and tried to start the car from completely off twice. Then we disconnected the battery.

When we reconnected the battery I noticed that the car dinged a few times after inserting the key for the first time and that the car was indeed equiped with a theft device; don’t know how I missed it the first time. Read a few things about there needed to be a certain amount of resistance that goes through the key to be able start the car so was indeed the ecu turning off the car.

Thanks much for your prompt replies & hope you all have a good day!