My 92 Aerostar suddenly quit.
The ignition spark checks OK but there appears to be no fuel flow as I have removed the fuel line at the filter and cranked the engine looking for fuel pumping in to a bucket nor can I hear a whirring sound of the fuel pump in the gas tank. There is no fuel flow. Checking the electrical system in accordance with my Haynes Aerostar manual was inconclusive as I could not determine if there was voltage at the electrical connector just forward of the fuel tank. The inertia switch is OK and passes a continuity check but there does not appear to be voltage at the inertia switch either.
Where is the fuse or fusable link for the fuel pump and should the voltage be 12 volts or something less (I measured approximately 7 volts at the inertia switch connector)?

How difficult is it to replace the fuel pump? Is it a saturday mechanic job or should I take the vehicle to a dealer?

 

The power source for the fuel pump is from a yellow fusible link through a relay. It also supplies the main power to the EEC, also through a relay. When you turn the key on, the relay is supposed to activate for a couple of seconds to pressurize the fuel lines. If you can not hear the pump during that time. do you hear a relay clicking?

Since you've accessed the fuel pump connector already, you can apply 12 volts from a battery to the fuel pump to see if it turns. The positive wire is pink with black stripe, and the negative wire is black.

 

Here is a good tutorial on in tank fuel pump issues and testing:
http://www.airtexproducts.com/AIRTEX...tex_TTS_09.pdf

I have been driving a mercedes diesel for the past 7 years and other clunkers before that so I have avoided a lot of these common yet expensive types of repairs, the last fuel pump I needed to change was held on to the engine by a couple of bolts and the trickiest thing was to coax the pin to stay up long enough to get the arm stuffed under.

But now we have these quaint and expensive in tank fuel pumps where you have to drain, and drop the tank and often need to replace not only the pump, but the sending unit and whatever is clamped on. My ex had this done on her sable, and the whole job with parts and labor came to around $500.

If I ever have to do this on my car, I think I will make a second tank about a half a gallon to house the fuel pump and then have a cheap electric fuel pump to transfer fuel from the primary tank. That way an in line fuel filter could trap any crud or water that came from the main tank and if the high pressure fuel filter did need to be replaced, it would be a whole lot easier task.

Also you can now buy just the fuel pump rather than the entire unit for a whole lot less money and then install the new pump into the sending unit assembly that option might save you a tidy sum if your sending unit is OK.

 

Back in 1994 I had to replace the fuel pump in my 87 Mustang. It was a real drag to drain the tank enough to drop it, as I had just filled it up before the pump failed, and the tank was baffled so a large hose could not get into the bottom of the tank. But at the time, aftermarket fuel pumps for the Mustang were readily available, and I was able to replace just the pump.

When I had to re-seat the gasket between the sender plate and the tank on my Aerostar, I noted that the pump was similarly replaceable. The Aerostar's tank is not baffled; the fuel pump pickup sits in a depression in the tank, so it's much easier to siphon out the fuel if you had to.

Roger, your idea of installing a secondary tank was actually implemented by this road racer named Scott Griffith in his 1986 Mustang. His purpose was to put the high pressure pump in a small tank that was kept constantly full by a high volume pump in the main tank. That way, when he takes those high-G corners, the high pressure pump will never starve from the fuel being sloshed to the sides. Of course, his Mustang is now in name only; it's been completely rebuilt under the skin.

 

I think the idea has merit due to several factors.

The expensive high pressure fuel pumps die from several causes:

1] Crud in the tank.

2] Overheating the pump because the pump requires immersion to stay cool.

3] Water.

If a cheap electric fuel pump was used to fill the secondary tank, most contamination problems could be thwarted by a filter.

If a fuel level sensor was incorporated into the secondary tank, then the high pressure pump would never be running while not submerged.

If you designed the secondary tank with a conical bottom and a drain, the high pressure fuel pump could be mounted a couple of inches above the bottom of the tank so any water that got through would not get sucked in and the design would allow you to easily drain off any water that did get into the secondary tank. Often on diesel vehicles they have a filter that has such a design and it also has a sensor to detect any accumulated water so you know when the thing needs to be drained.

The design would also allow you to use any high pressure pump not just one that Ford designed. This way if for instance of a Chrysler pump was cheaper or more durable, it could be used. The only thing that would matter is the pressure and volume that it produced.

You could also have a bit of latitude as to where you where you mounted the secondary tank. It might be better if it were mounted in a place where it was a lot easier to service should the need arise.