Thank you for being a valued part of the CNET community. As of December 1, 2020, the forums are in read-only format. In early 2021, CNET Forums will no longer be available. We are grateful for the participation and advice you have provided to one another over the years.

Thanks,

CNET Support

General discussion

94 v8 Grand Cherokee - Fuel pump pressure delay when cold

Jan 9, 2008 1:19AM PST

When cold - below 40 degrees - the fuel pump will not run until the engine is cranked for about 45 seconds. Then your hear it run/pressurize and the car starts right up.
I replaced the Fuel Pump, Fuel Filter, Fuel Line to Fuel Filter, Coil, and she still fails. When the outside temperature is warm the pump pressurises when the ignition key is first turned on and she starts right up. Changing the mentioned parts did not affect the condition. Would really appreciate any help / suggestions.

Discussion is locked

- Collapse -
Need info
Jan 10, 2008 10:07PM PST

There aren't many things that would cause that...

My guess would be that you have water in your system somewhere, but it's just as easily an electrical problem.

What about humidity or outseide temp vs. engine temp?

If you can't hear the pump running when it's cold but can when outside temp is warm, I would check the electrical connections. It may be gunked up with salt/road stuff and the cold or humidity is disconnecting or shorting the connection.

- Collapse -
I think just for giggles...
Jan 15, 2008 4:27AM PST

I'd replace the fuel pump relay. Should be in the engine compartment. I don't have any other ideas, but that's cheap and easy to do, and the first thing that came to my mind.