After running a battery of tests (pun intended) on the electrical circuit to the fuel pump on my 98 Contour, I have determined that: 1) the power ground to the fuel pump is faulty (bad ground) and, 2) there is a load parasite between the fuel pump relay (pin 87) and the power feed from the ignition relay. The parasite causes a load drop from 12.56 to 5.5 on the volt meter. I can deal with the parasite, but before I mess with the ground, I would like to know where the shorting bar is. Otherwise, I will have to ground the unit elsewhere on the vehicle. Where is the shorting bar for the fuel pump located on this model? Anybody know outright or where I can look up this information? Thanks.

 

Not knowing where you reside or under what conditions the vehicle has been driven , a suggestion; start at the negative terminal of the battery and check (requires removing ,cleaning and reinstalling) each ground connection you can find especially those that go to the sheet metal of the car. Since any one of them could be supplying the ground connection to several components, best to do all of them. It doesn't take that long and will provide some good information as to where they are since not all vehicles are the same. Many times the ground points are painted over and look OK, but are not clean underneath where mounted. Sometimes it requires a little detective work to hunt for them, but when done the result is good operation.

I would like to help with your voltage measurements, but am not clear exactly where you are getting these measurements and whether the circuit is loaded or not. Just what kind of problem does the system seem to have performance wise ?

 

Hanky, the load readings were taken at various points along the power wire that runs from the fuel pump relay to the fuel pump connector (4-pin). I started at the pump and worked back getting the same reading (done while cranking). FYI: pump circuit has continuity and when connected direct to the battery using an alternate ground location the fuel pump worked like a champ. When I got to the fuel pump relay socket it showed a load drop described above. I took the underhood fuse box (often referred to as the battery junction box in schematics) apart today. This box holds the fuel pump relay. An examination reveals that the "tooth" that corresponds to the fuel pump relay power is loose. This tooth is part of a busbar that feeds power to other relays (i.e. horn, low beam, fuel pump, etc.). Only the tooth connected to the fuel pump relay is loose. I suspect that it makes only intermittent or loose contact and is the load parasite (the battery drains in two to three days). My search for a replacement fuse box has been fruitless so far this morning. I could rig a switched bypass since the connection to the pcm is still good. I am debating the pros and cons of this.

The name of the actual ground connector is "station bar #4". It may be in the trunk, as it seems to be the location (according to schematics) for the rear tail lights and brake lights. I will follow your suggestion nonetheless.

Know of a source for the fusebox?

 

Hanky, forgot to reply to your question about what the system problem is. The fuel pump does not energize when you turn the key in the ignition switch. The car cranks. When the pump is connected direct (with in-line fuse, of course) and grounded, the pump runs and fuel reaches the injectors, and engine fires. I hesitate to by-pass the fuel pump relay, although it is a really easy task to perform. However, if for some reason the impact switch does not engage in an accident, then the fuel pump will continue to run unless I manually turn off the switch.

 

Some vehicles used the inertia switch in the hot supply to the pump and some used it in the ground side. Depending on which side the inertia switch is inserted , if you run a replacement to the switch you should still get the benefit of the protection the switch offers. What are your thoughts on that?

 

Worked like a charm! Sorry I didn't reply sooner. I spent the day working on my beast. Ran a hot line with a 15A fuse and patched into the fuel pump power wire after the fuel pump relay. Downstream of the inertia switch I patched in the switch (mounted under the steering column). The pcm still controls the read from the ignition switch, so the pump only energizes with the key in start/on position. The additional switch serves as anti-theft device (like in the days before pats...okay so I'm way over 50).

However...although the engine fired up, it's running too lean. Do you know the appropriate length for the intake air resonator? The old one was damaged in a fire and leaks. Can't make a new one and plug it without knowing the correct length.

Thanks for all the great help!

 

In case you might be looking for parts for the vehicle that your dealer cannot get try this site, www.vintage parts inc.

 

Hanky
roger that. All is much appreciated.
Hemionus