Electric fuel pump problems

[western77]

I put a new 6 volt electric pump to replace the mechanical one. I hooked it to the ignition switch and it pumped fine with the ignition turned on. The engine starts and runs for a minute and dies. After searching and cleaning wires checking voltages I found that the pump stops as soon as the engine starts, the carb runs out of gas engine stalls and the pump starts up pumping again. The only hot line that I have found to make the engine run and the pump run is direct to the battery. What is going on? My hair is white and back is sore, I don't know my next step! Thanks JB

[LuckyFordGuy]

Put 10 gauge wire to the pump had same problem years ago should work

[western77]

Lucky ford guy, did you run it off the ignition switch?

[western77]

Yes the pump is grounded with the mounting strap.

[V8COOPMAN]

How about some details on type of car and exactly what type of ignition switch? Might help us figure-out what you're dealing with. DD

[JSeery]

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First thing I would do is check the voltage going to the electric fuel pump. Would take two people most likely, but see if it is a pump issue or if there in no or very little power to the pump when the engine is running. May have it wired to a no power in RUN source or a source that can not provide the required power while running. As Lucky said, could be an undersized power wire.

[LuckyFordGuy]

No I ran a different switch so I turn it on when I need it works great Rog

[Vic Piano]

On the cars and trucks I've installed electric fuel pumps in, I run a hot wire from the side of the ignition switch that is hot when the ignition is on, to a "kill switch" mounted in an easy to get to, but hidden from view, location under the dash, etc. I run the wire (using the correct gauge for 6 or 12 volt) back to the fuel pump. The pump should have two wires, one hot and one ground. If you are hooking up a 6 volt pump, you will (in most cases) have to reverse the wires for a positive ground system. In other words, the hot wire becomes the ground and the ground becomes the hot wire. I run the electric pumps as primary pumps, and I convert the stock mechanical pumps to 'pass through' type, to avoid any chance of fuel getting into the crankcase, while maintaining the stock look under the hood.

[30-9]

Vic two questions:

How do you make it pass thru - pull the rod?
Why not use electric as prime or backup and mech as primary?

[Vic Piano]

Originally Posted by 30-9

Vic two questions:

How do you make it pass thru - pull the rod?
Why not use electric as prime or backup and mech as primary?

I'll answer you last question first; the way Ford set up the OEM fuel pumps (on top of the intake manifold) if the diaphragm ruptures, and you have an electric fuel pump hooked up to feed through the mechanical pump, you'll be pumping gas into the crankcase... that's not good!

Here's how I convert the OEM fuel pumps to 'pass through' pumps. First, I gut the pump, removing all moving parts. I use (for lack of a better term) sliding closet door thumb pulls, you can find them at Home Depot, Lowe's, etc. The larger diameter ones are a very good fit when placed into the top portion of the fuel pump (you may have to grind off the lip for a tight fit). This creates a reservoir for gas. I use JB Weld to fill in the gap. After the JB Weld is dry, I reassemble the top and bottom sections of the pump, using the diaphragm to separate the two sections (just as the original pump did) this gives the outward appearance of an OEM pump, when it is installed. As a side note, I leave the push rod in the block and, I always carry a 'known to be good' mechanical fuel pump in the vehicle, just in case there is a problem with the electric pump. I had talked about doing the fuel pump conversion with Marv, here on the FordBarn, and he actually did the first conversion for me. It is easy to do and it maintains the OEM look under the hood, if that's important to you. One more thing, when using an electric fuel pump as the primary (or only) pump, you should always install a 'kill switch' to shut off the flow of gas if it becomes necessary. Hope this helps and was not too long winded.

[Bruce Lancaster]

You show a Model A...is the pump in an A??
Stock Model A setup has a switch that controls the coil-to-points side of the circuit, NOT the hot wire to the other coil terminal!

[30-9]

No thank you very good information & American inginuity - I like that

But if u use the pump (with a kill switch) just to prime or when u have vapor lock - u would not have to worry about gas getting into crank - right? Keeping mech to do its job

[Vic Piano]

With the 'new' gas, and the way it eats rubber, I would never use an electric pump as a prime or secondary pump. But, that's just me... Oh, getting rid of the dreaded Vapor Lock is another advantage of using an electric fuel pump, at least that's been my experience here in Central Florida, not to mention the steady fuel pressure they provide.

[western77]

I have a 53 mercury engine in a 41 pickup body. I am not using the resister in the ignition system but have the 41 ignition switch. I ran a hot line from the switch on the same line as the wire to the coil to the pump. That is hooked to the black wire or neg. coming out of the pump. The brown or positive wire comes back to the cab to a toggle switch so I can switch the pump off manually. I plan to use this pump as my only pump. I have a 6 volt positive ground system. This is a 6 volt pusher fuel pump. I have tried hooking to the gauge terminal also, no luck. The only way I can get the pump to run and the engine to run at the same time is if I have the pump is wired to the battery at the battery! I will be installing a number 10 wire tomorrow to see if I am starving it for current. I tried a relay on the coil with the pump wire before the relay, no luck. I took the switch apart and cleaned the three terminals, no different.

[George/Maine]

If you have a 6 volt relay and has a coil pick + to - and has a neg post and pump side this take the amps from battery to run pump and not thur ign switch
If you can trip relay and not pump this should work for you.
I would run a larger wire from relay under dash to pump near tank is what they want.

[western77]

Tomorrow I will try to run the pump on the relay rather than the coil. Also add the heavier wire. Thanks, JB

[39topless]

With a positive ground system, it seems to me that the lead wire to the pump should be negative (run through a "kill" switch) and originating from the ignition switch. The positive wire on the pump should be grounded to the frame.

[George/Maine]

I would use parts that use less amps and better switch.
Use a 6 volt coil for a 53 mercury round 49-55 coil.
I used a start key switch in place of the starter button and run every thing from that switch. 12 volt relays are easy to find may not be able to find for 6 volt.
You don't want to waist amps to run pump.
Frame is good ground and longer wire to pump may want larger.

[JSeery]

Here is a source:

http://www.newark.com/durakool/dg85b...alog&source=CJ

Durakool DG85B-8011-96-1006-M1

TE Connectivity / Potter & Brumfield 1432873-1

Early 1950-60 VW uses them:
Bosch SPDT

6V 30 amp Relay

0332204001

Used as dimmer relay

In 1950 to 1966 VW

Also listed as:

Merced 0035340245

Porsche PCG61510100

John Deere AR91168

[FireEngineMike]

Could you explain, in detail, for us non-electricians how the relay and switch are wired for both a secondary and primary electric fuel pump. Please start with the power source wire and end with the fuel pump. Thanks. I plan to install an Airtex E8902 in my stock 1940 95 hp panel as a secondary pump only.
For those worried about OEM fuel pump diaphragm failure with ethanol gas, CharlieNY will rebuild your pump with a diaphragm that stands up to ethanol.

Originally Posted by JSeery

Here is a source:

http://www.newark.com/durakool/dg85b...alog&source=CJ

Durakool DG85B-8011-96-1006-M1

TE Connectivity / Potter & Brumfield 1432873-1