Puzzling: Running out of Gas, kind of (Ford Contour)

Sounds as if the fuel pickup, inside the tank, is bent or broken or holed such that when the fuel drops below a certain level, the pickup sucks air even though there's fuel in the tank.

DS

Inside the tank fuel pumps like to be kept cool by being submerged in fuel. Your pump may be starting to get flakey if you regularly run her down to the fumes.

Regards, Al.

^^^^^^^^^^^^^^^

AOL. I have a 2000 Focus and it does not have a return line from the engine to the fuel tank, just a single supply line from tank to engine. This means that the only way the pump is kept cool is by being totally submerged. Fuel injection systems with a recirculating design keep the pump cool even when there is very little fuel left in the tank by continuously pumping fuel in a loop between tank and engine.

I suspect the 2000 Contour may use the same type of system as my Focus. Focuses are known for having more than their share of fuel pump failures and I suspect this sort of behavior may be the reason why.

Look again.

DS

Actually he is correct, there isn't a return line. From the Ford Service information:

"The vehicle is equipped with electronic multiport fuel injection that is supplied by a new electronic returnless fuel system. The powertrain control module (PCM) receives pressure information from a fuel pressure sensor mounted on the fuel injection rail. The PCM is able to maintain constant fuel pressure by varying the fuel pump module output.

"This is accomplished by increasing or decreasing voltage supplied to the fuel pump module. The returnless fuel system offers improved economy, lower fuel temperatures and decreased fuel vapor in the fuel tank."

Ed

Approximately 10/12/03 08:38, C. E. White uttered for posterity:

Wonder what the real reason for this is. I also have a fuel system with no return line, on a 95 ZJ. I wonder if there is any emissions, etc. benefit from not having the return line or if it is just simply cheaper. If the return line were to come back in the lower part of the tank, can't see how it would add any vapor and having a hard time with the fuel temperature claim as well.

The "real" reason is stated.

Yes, there is an emissions benefit. If fuel is circulated up towards the engine, it -will- absorb heat. If it is then returned to the fuel tank, eventually the temperature of the fuel will increase. Warm fuel evaporates easier than cool fuel. Warm fuel increases the pressure inside the fuel tank increasing the load on the charcoal cannister and complicates the evaporative diagnostic monitors that are part of the OBD2 protocol.

You should familiarize yourself with OBD2 Evaporative Emissions requirements. Many OEMs are going to returnless fuel systems. Given the difficulty of finding and fixing evap leaks, anything that eliminates connections/fittings at the fuel tank is a good thing.