Empty the fuel tank of a 1997 Mercury Sable

Unfortunately the tank of our 1997 Mercury Sable got filled with diesel and the engine was run until it quit, so I had to find a way to get the diesel out so we could refill it with gas.

I tried to siphon the fuel out, but was unable to get a hose down into the fuel tank.  I tried several types of hoses and a garden hose got the farthest, but still wasn't deep enough in the fuel to actually siphon it out.

So, after about two hours of online research, I found how to empty the tank, and I will consolidate everything I learned into one post so if somebody else has the same issue I had, they can hopefully solve it easily.

First, I disconnected the fuel line at the fuel filter.  It is located under the car in front of the rear wheel on the passenger side.  It looks like a metal can and has fuel lines connecting to it.  All you need to do is take off the clip and pull the hose off.  You probably won't need tools, though I used a screwdriver to push the catch on the clip down so I could get it out.  I live on dirt roads and it was caked with mud.  If you take the hose off the front of the filter (the cleaned side) you can connect a hose to it to run the fuel to a bucket.

The next problem I ran into is when you turn the key on the fuel filter only runs for about a second to prime the line.  It would take too long to sit there turning the key on and off to drain the whole tank.

What I found easiest was to locate the Inertia Sensor in the trunk, on the passenger side.  It's near the top, behind the cover and should be easy to get to.  It has a red/black wire and a green/yellow wire connected to it.  It is what is responsible for shutting off the fuel pump if you get in a wreck.  You can see it in this schematic:

I pulled the plug out and connected the red/black wire to the positive terminal on the battery with an old piece of wire I had sitting around.  This bypasses all the relays and runs power directly to the pump.

It takes about an hour to completely empty the fuel tank with the pump, so I hooked up a battery charger while it ran to keep from draining the battery too much.

After all this was done I put about 10 gallons of gas in the tank and cranked the engine for 10 seconds at a time.  It took probably 10 tries but the car fired right up and is running fine now.  I'm glad it seems very tolerant of diesel.