Hey all, I joined to get some info about getting my girlfriend's 73 v12 convertible running. I've gone through a lot of the threads and learned a ton, but I have questions about the fuel pump. Am I correct in thinking that the fuel pump should turn on when you turn the key on? The pump doesn't seem to do anything when you turn the car on, no hum, buzz, vibration or anything.
I also haven't been able to locate a fuse or relay for it.
I was hoping to be able to use the pump to remove the 25 year old gas from the tank.
As a plan B, is tank removal a big deal? It seems like it should come out from the top.
Any info would be appreciated, thanks.

 

When ignition is turned on the fuel pump should pump and retain a pressure in the fuel line. The fuel enters the fuel rail on the right hand side of the engine and there is a non-return pressure relieve valve on the left hand side that allows fuel to return to the tank when the pressure in the fuel line pops the valve. Normally, when you first turn the ignition switch on after the car has been sitting for a short time, you will hear the pump make a ticking sound in quick succession until pressure in the fuel line builds up, then settles down to a slower paced ticking as the fuel pump keeps pace with the non-return pressure relief valve. These pumps are notorious for not working, or working randomly. If you can't hear any ticking whatsoever, either the line fuse is blown, or the pump is not working. Give the pump a few firm bumps with your hand, with ignition switch on. This will often shock the pump into working if it just jammed. If you hear any ticking at all when you tap the pum in this way, it clearly means that that power to the pump is being supplied. A multi-metre can also be used, with the ignition on, to see if you have power at the pump.

If when you bump the pump, it starts ticking and then stops, its a sign that the pump needs to be removed and serviced.

You will find the fuse behind the cluster of gauges in the centre of the dash panel. If you look under the top padded section of the dash board, and just above the gauges you will see a retaining knob at the top left and top right corner of the instrument panel. Unscrew these and the instrument panel will swivel down via hinges at the bottom of the instrument panel.

The best way to drain and clean the tank is with the tank out. However, there is a drain plug at the outside, bottom of the pump that can be used to empty the tank. A reasonable job of cleaning the tank can be made by dumping fuel into the tank with the drain plug removed and a container to catch the fuel. The dumping of the fuel into the tanks tends to stir up any sediment that may be in the bottom of the tank. You can also remove the plate on the top of the tank were the fuel delivery and return pipes are located. This will gain you access to the inside of the tank. If you remove this plate, the gasket between it and the tank will have to be replace.



Regards,

Bill

 

edoz - welcome to the forum, when you have a moment, stop by the new member section and post an intro:

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