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Question about Dual Polarity Electronic Fuel Pump - How to Connect Wiring?

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B

blueskies

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The fuel pump is a new Hardi Electronic Fuel Pump. On the label it says, "Dual Polarity AZX1332G." The box also has the numbers 1112-1 marked on it.

I want to connect this to my Positive ground system in the BN4. The instruction sheet in the box only has a diagram for connecting the pump to a Negative ground system. The pump has two electrical terminals, one with yellow paint on it and one without paint on it. The instructions indicate that the yellow is for the Positive connection and that the other terminal is to go to Ground.

Now I am wondering whether this actually is a dual polarity pump. Any ideas on how to connect this to the Positive ground system? Yellow terminal to positive or negative? I do not want to fry the pump or some other part of the electrical system.
 
Well since it has only two terminals i would think the polarity is marked on the pump case someplace close to the terminals..
IF a schematic was included that may be more useful in determining the connection set up for this pump.
 
Check to see if there is continuity between either terminal and the pump body. I suspect that the "dual polarity" is due to the two terminals(positive and negative) being fully insulated from the pump body. This means you just need to figure which is positive and which is negative. Couldn't see any markings on pump in picture.
 
I'd call the vendor.
 
I called the supplier as well. They said to connect the negative power wire to the terminal that one would normally connect the positive wire to in a car with negative ground (earth). I'll try that and let you know if the pump goes up in smoke!

Now, for the next issue with hooking up this pump. New fuel tank, complete with a welded in place fuel pickup. New copper fuel lines - one to go from the tank to the pump, and one to go from the pump to the engine. One is half the length of the other, so obviously that one is to use from the tank to the pump. One end of that shorter fuel line has a soldered on female connector and the other end is just copper tubing with a loose male compression type fitting waiting to be tightened. But both the tank fuel pickup and the pump have male fittings. I tightened the female fitting onto the tank. My cans of brass fittings had nothing suitable in them to connect the copper tubing to the fuel pump. Then I spent several hours today going from supplier to supplier - including an import farm equipment dealer, NAPA, a hydraulic specialist, a heavy truck parts supplier, and several plumbing suppliers - looking for an adapter to go between the fuel line fitting and the pump fitting, or a female compression fitting. No luck. The British thread used on the Healey fuel line system does not match up to anything in usage here.

Can anyone tell me what that thread is called and where to find an adapter or female compression fitting? Better yet, can someone point me to a supplier of a fitting that will work? The people who sold the pump said they had not heard of this problem before and did not have an immediate solution. I ran into a similar problem with the other new fuel pump that I already have; no one had fittings to make the connections. So I bought all new parts, but they still don't fit with each other.

It is not tapered pipe thread, other North American plumbing thread, hydraulic brake thread, air brake thread, import tractor thread, etc, etc. I suspect it is British BSPP thread, which I may be able to order on line, but can't be sure of that.
 
The threading on the original fuel pipes and tank is 1/4" BSPPT - British Standard Parallel Pipe Thread.
Adaptall, Inc. 1-800-463-8134 can provide an adapter to AN6 fittings, and might have other applications.
Bob
 
An update. Problem solved, I hope. I had another fuel tank - one that the fellow that I got the project from had rebuilt from an original BN4 tank. He was a welder and auto body instructor who suffered health issues and could not complete the project, and I'm hoping that he did good work on this tank. That tank had a female fitting on it, which likely is correct/original for an early BN4. Seeing that, I thought that the new fuel line would work on that. But that tank required a larger fitting than the one that came on the new reproduction fuel line. So I dug out the original steel fuel line and used that. It actually looked to be in very good condition. The old fuel line connected up perfectly to the new fuel pump too.

So now I have a new fuel tank and a new fuel line in storage, while the old tank and fuel line are back in the car. Maybe the new parts will come in handy for the next project. But it still is a shame that the reproduction parts, that are supposed to work with each other, don't fit.
 
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