94 Escort LX Wagon fuel pump assembly questions

The part you saw is a pulse dampener. The fuel pump produces pulses or spikes in the fuel pressure and this part smooths them out. I believe it is a spring loaded diaphragm, an accumulator of sorts. Why the metal cap? Probably easier to assemble, maybe more durable than a 2 piece plastic housing bonded together. I really don't know. Tom

Thanks for replying Tom. I'm leaning toward "accumulator" since there are no moving parts visible inside (unless the funky rubber seals with plastic clips or possibly flexing metal cap count). I did see something about an accoustic dampener though. Anyway, I wonder how often pumps are replaced for bad check valves when it was a leaky accumulator/dampener seal (that gets reseated when the pump is replaced) all the while. I'll post links when I find out more.

Anybody know anything about accoustic pulse dampening? Is it simply a resonator cavity?

Regards, Bill Liles snipped-for-privacy@netscape.net

It is a check valve. It's job is to prevent the fuel from draining from the fuel lines when the pump is off. This keeps the fuel lines full so that fuel pressure at start up is very fast. Many times there is also one on the return line. Many of the check valves incorporate both the return line and the supply line.

Quoted from shop manual: "The sequential multiport fuel injection (SFI) system uses a fuel level sensor (9275) and the fuel pump (9350) which includes a high-pressure fuel pump and a fuel level sensor. The fuel tank (9002) has an internal cavity (reservoir) in which the fuel level sensor and fuel pump rests. This design provides fuel pump operation during extreme vehicle maneuvers and steep vehicle attitudes with low fuel tank fill levels.

The fuel pump and the fuel level sensor are mounted as an assembly. The outlet of the fuel pump includes a valve that maintains pressure in the fuel system after the vehicle is shut down. This pressure retention helps prevent long cranking times during hot-starting conditions. "

Thanks for replying Thomas. The part is NOT a check valve -- it's hollow. It's my understanding that the check valve is built into the electric pump. Perhaps you didn't see my response to Tom's reply.

By the way, my previous posts were only on USENET: rec.autos.tech, alt.autos.ford via google groups. I don't understand how they get copied into this forum. I found this reply quite by accident and had to register to respond to it. In fact, my response to Tom's reply that is shown here doesn't appear on google groups yet!

Regards, Bill Liles snipped-for-privacy@netscape.net

It is a check valve as per shop manual. It is not hollow, but a pressure operated diaphragm.