bmflyfish: Sorry not trying to hijack your thread. Yes, as installed you can use you installed fuel pump to pump the tank dry. As mentioned, make sure you have a good filter between the tank and the pump. I recommend a clear filter so you can see if it is filling with sediment and so you can see when the tank goes dry. REPLACE the filter after you finish pumping the tank dry. Listen to the pump while you are pumping. If the sound of the pump changes, stop the pump. Then check the tank and the filter. Either the tank will be dry of the filter will the clogged.
Jason S
Good idea - got a schematic? Not sure how you are connecting it into the oil pressure sender.
Thanks
It's been almost 10 years since i installed an electric fuel pump into anything, and I did it then with my father. We did this to a Ford 460, but the basic design is true for any engine.
The wiring side is really not more complicated than wiring a set of driving lights through a relay. It is the same basic schematic. If you use the right pressure switch, you should not have to bypass for starting, which would make the circuit much more complicated.
Making that connection can be the easiest part, and probably would have been clearer if I had done a better job describing it.
You will need a pressure switch. I has to be the of the variety that is 'on' when pressure is above a certain value, and 'off' if it is below that value. Finding the right switch will take some research, and probably a bit of trial and error. I remember the first switch we used worked great until the engine came off of the choke and idled down. Then the oil pressure wasn't high enough and the fuel pump switched off and teh engine died.
One thing to consider is, depending on the control signal voltage requirements of your relay, you might be able to splice the ground wire for the relay into the wire from the sending unit. But, doing so might affect the accuracy of your oil pressure gage.
The actual connection is, like I said straight forward.
If you have an aftermarket oil pressure gage, follow the sensing line to the connection in the block.
If you still have the factory electrical gage, you have to work a little harder to find the connection in the block. Find a wiring diagram for your year and determine the corect wire color for the oil pressure sensor. Make sure you have the oil pressure wire and not the coolant temp wire.
Once you have a presure switch and have found your oil pressure sending unit, determine thread sizes. When you have your thread sizes it's time for a Home Depot trip. You will need a brass 'T', any appllicable adapters (also in brass), and some teflon tape. You wil want to minimize the lengths of tube that you use because the longer that it is the faster the metal will fatigue from engine vibration. Depending on location of sending unit a bracket can be fabricated to support the assembly and minimize vibrations.
Assemble the pieces to form an assembly and connect it to the block. In some cases the 'T' assembly will need to be connected to the block before you install the pressure sending unit and pressure switch. Once the pressure switch is installed, its just a simple matter of wiring the relay and pump.
Something else to consider is, depending on method you use to connect the relay, you could use the relay as a form of theft deterrent. Similar to a kill switch, but more obvious. You pull the relay when you park the jeep and no one will drive it away.
I might be skilled enough in MS paint to scribble up a schematic if you need one. Let me know.
out of the bottom of the tank and plug your filter. But I've done the same thing in the past without any problems.
