Here are the pics of my fried fuel pump link lead. Apparently it shorted out and melted the 2 sides of the harness together inside the fuel tank. Thank goodness fuel systems are sealed and pressurized or it could have been a real disaster. Thank you JagTechOhio for the information you gave me in diagnosing this problem. I never would have imagined the harness would have shorted out and fried like this.

 

yes its a allto familiar problem

 

The first time I saw this, I couldn't believe it. The FAA blamed a similar problem for blowing up an airliner, I think it was a 747 in about 1995 that went down off Long Island. Why it is that a nearly empty tank full of fuel vapor isn't ignited by arcing from a failed connection like this is something I don't understand. But I've seen quote a few burned link leads too, and never heard of a worse consequence than a stalled engine.

 

Hey Sterdy, if you haven't worked out a solution yet, let me know and I will post it here.

 

Actually I did figure out a solution for the problem. I was having trouble finding a new link lead harness on my ever depleting budget, so I made my own solution. I used the wires for a fuel level sending unit and wired directly to the fuel pump. I then drilled a small hole in the evaporator flange just big enough to pass the wires through. I then connected the new wires to the outer lead harness (blue/red and black wires) in the trunk of the car, thus completing the original circuit for the fuel pump wiring. Then to seal the hole I drilled in the flange, I sanded the top of the flange around the new hole and sealed it off with some J.B. Weld all-purpose. I also left the old harness in the flange with the o-ring still on it, so that there wouldn't be any pressure escaping from the original harness. I know it is not the proper way to fix the problem, but given what I had to work with, and my fairly extensive knowledge of mechanics, I believe that this will prove to be not only an acceptable repair, but safe as well. Now my Sovereign is running tip top again. I start my next project this week as soon as the parts come in. Unfortunately, the wheel bearing in the passenger rear wheel has been causing me some problems for some time now, and has finally rendered the car inoperable. I have the new bearing kit coming from Coventry West. I ordered it on Sunday, so I am hoping I should get it tomorrow or Thursday. My neighbor has a good friend that has a hydraulic press in his shop, so he said he would get the bearing swapped out for me at no cost. Once that is done, I will hopefully be able to start focusing on the more minor issues with the car, e.g. replacing rusted fuel lines and brake lines, and body and paint work. Thank you again for all of the help that you have provided. It has really been a godsend for me. I am a great at-home mechanic, but this is my first Jag, and I have run into a few problems that are out of my knowledge base. I'm sure I'll be posting new questions/problems in the future, and look forward to much more of your excellent help and advice.

Thanks again,
Dan A.
Cedar Lake, IN

 

I almost forgot. To answer your curiosity about the vapor in a near empty tank, the reason it won't ignite is because of two main reasons. The first being that the fuel system, including tank, is pressurized while the vehicle is running. This pressure works in combination with the vapor escape/release hoses that all fuel tanks are equipped with. As the pressure is built inside the tank, it forces the very explosive fuel vapor out through the vapor hoses thus rendering the fuel harmless. I was only in my early teens when the plane crash you refer to happened, but I do remember it. If the FAA's finding were in fact correct that an arc caused the vapor to ignite, it is likely that the vapor hose(s) was/were clogged. This is why it is recommended that mechanics blow compressed air through those hoses any time they are working with the fuel tank. Mostly it is just preventative maintenance, but they have been known to clog from time to time (though I suspect with your credentials, you are already aware of this).

 

The 90 degree connector in the picture above: you cut the top off flush, pull out the terminal blades, drill each hole out to 1/8", and feed two 16 gauge wires through. Splice to the existing link lead, refit the terminal connector and goop it with sealer.