Electric Fuel Pump Installation Diagram
I energize the pump with an oil pressure switch that closes at 10 psi. I have a momentary contact toggle wired in parallel with the oil pressure switch so I can hold it on if I need to and an indicator light to tell me when there is power to the pump. I've seen too many relays stick on when the contacts weld together. Late 80s and 90s Ford fuel pump relays seemed prone to failing on. If the battery goes dead in a few days of sitting, it is likely the fuel pump is running.
You do need an oil pressure or inertia switch or both wired into the system to shut the pump off in case of an accident or broken fuel line. The inertia switch can't tell if the engine isn't running so it would allow fuel to pump with a broken line if you don't turn the switch or key off. When Florida had rental car license plates, thieves would target Ford rental vehicles. They would bump into them from behind which tripped the inertia switch. Then they robbed the stranded tourists. When did electric fuel pumps start to pull so many amps that they suddenly need a relay? Is this an internet phenomenon?
I've had an ass load of electric fuel pumps on 40s and 50s style hotrods (which sounds like what he was talking about) and never once used a relay. I'm talking about carbureted cars and not the fuel injected modern POSs SWs Dupree's, ACs.none of them ever required a relay. A fuse yes but never a relay.
How to install and wire an electric fuel pump. Fuel Pump Installation. The diagram in the center uses a relay. The best location for mounting any electric fuel pump is the rear of the vehicle. JEGS 15913 Fuel Pump Electric Installation Instructions. How to re-wire a fuel pump. One mod worth doing is re-wiring that fuel pump. How to re-wire a fuel pump off a relay. On your web site it shows this diagram.
What happened in the 80s-90s and 2000s that makes a relay necessary? What did I miss. Was there an epidemic of burned up hotrods that didn't use a relay?
A relay to me is just something else that can and will fail on the road. If it's not necessary.I don't want one on my hotrod.
I believe in the KISS system.Keep it simple stupid. Just another unpopular opinion I guess.
I've got a lot of them. Click to expand.It's not always about AMPS, sometimes it's about CONTROL. If you put a new switch on the dash each time you added something electrical, you could end up with a not so simple dash.
Then each time you start the car, you need to flip a bunch of switches, then remember to flip them all off when you park. Using a relay on the existing (60 year old) ignition switch will allow it to turn on an unlimited number of devices simply by turning the key. Then you can add safety devices like an oil pressure switch that may not have the current rating to run the pump.
Sometimes being too simple is kinda stupid. Besides, the OP wanted to learn how to wire a relay.
He didn't ask if it was really needed. Click to expand.I agree I'd shit can the toggle switch too. When I was a kid I wanted a toggle switch to show off the fact that I had an electric fuel pump. Flip the switch and hear the pump click away.
It didn't take long for me to figure out that a separate switch was a PITA. I just run it to the 'run' terminal on the ignition switch. That 60 year old switch was engineered to carry twice as much amperage for the old 6V system than a modern 12V system uses and I've always used them with no problems. I do check them out before hand though. Remember I'm are talking about old time hotrods and not modern streetrods with all those bells and whistles. Click to expand.I must admit I have never checked the current rating on an electric fuel pump but IMHO it's nothing to be concerned about. I do use an inline fuse like the ones on the radios before they became standard equipment.
That's probably before your time. I'm an old fart. I personally like the old looking switches, original ign switches and starter buttons etc. In fact I once wired a horn relay into the start circuit of a SBC just so that I could use an early Ford starter button on the dash simply for looks.
It was overkill but the look was important to me. Train Simulator 2013 Torrent Cracked Software. I could have used a generic starter button but I wanted that old Ford look.
Electric Fuel Pump: How to Do It Right Want an electric fuel pump to last forever and work right? We're going to show you how to install it and wire it up the correct way! Ok, let's talk about electric fuel pumps.