Mechanics

INTERMITTENT FUEL PUMP IN COLD WEATHER

2002 Ford Ranger • 6 cylinder 4WD Automatic • 110,000 miles

I have a 2002 Ford Ranger with a V6 4.0L engine. Periodically in cold weather, it will not start. After having this occur several times, I began to listen for the fuel pump to energize before starting. If I didn't hear it energize, it wouldn't start. After turning the key on an off several times(but not turning the engine over), it will energize the fuel pump and then it starts.

This only seems to happen in cold weather. Last winter, a mechanic swapped a couple of the relays around and it worked fine. But we never really had much cold weather after that and it started without any problems all spring, summer and fall. Now that winter is here the problem is back.

Any ideas on what the problem could be?

Thanks.
Avatar
Cjc
December 4, 2010.



Did you guys check the fuel pressure yet? It could be either a bad electrical connection at the pump, or the pump is on the way out.

Merlin2021
Dec 4, 2010.
Ok I have the same problem. At first it would only happen when I filled the tank up all the way. I thought it would have been a fuel pump relay going bad so I switched it around and got a new one and it still did not fix the problem.

I'm thinking about replacing the fuel pump cause I have no idea what it is so any idea would help me thx.

Tiny
Arl0
Dec 24, 2010.
This is my third winter with this problem. I have narrowed it down to this. 1. Fuel pump connection (doubtful). 2. Key switch (maybe). 3. Anti theft module (quite likely). I think it could be the anti theft module because it's only when I try to start it. Once it's running, it works flawlessly. And it requires a second relay to pull in when starting. After it's running, I think the fuel pump relay seals around that AT relay. I have bypassed the fp relay and still have the problem but I hear a secondary relay pull in. To eliminate the fuel pump from the mix, I plan to put an electric heater (with fan) under the gas tank and heat the gas up a bit. Here's the print

Tiny
Pk1948
Feb 23, 2012.