wiring electic fuel pump

[airman]

I am going to go electric and I'm wondering where you wire this into your circuit? Separate switch or key on or both? Do you just ground to the frame then? I wouldn't think it would be good ground right to the mounting bracket.

I have also seen with the Holley red pump that it recommends a safety shutoff switch? It looks like a pressure switch. Do these things ever go too high in pressure?

If I could get a few ideas from the "been there and done that" crowd...

 

[74bronc]

Get yourself a fuel pump wiring harness/relay from summitracing.com and wire it to switched power and ground to the frame. Good switched power sources are found at the fuse block. I typically use the radio wire to switch the relay. Draws almost no current to switch a relay. Good to go. If you don't go the relay route, at least fuse the power line

summitracing.com Part No. BGI-171035

20 bucks

 

[cro_bronco]

I would use a relay as well. Energize it from a keyed power source.Feed it from the battery and fuse this line. that way you don't overload the original wiring and if the pump shorts out or something it will blow that fuse. Go ahead and ground the pump on the frame it should be fine.
The safety switch you are talking about is used to shut the pump off if the oil pressure drops too low. You need to bypass the safety during start up or you'll crank the engine until the oil pressure comes up high enough to close the switch.

Good Luck!

 

[Broncobowsher]

Relays are good, espically for old, aged and stressed stock eletrical system.

A good trigger source is the "I" terminal on the voltage regulator. Unlike radio or other taps, it only turns on with the ignition in the Run position, not accessory.

The oil pressure safty switch is a good idea. Engine will run without oil pressure only as long as there is fuel in the fuel bowl(s), then stop. Also prevents hydrolocking the engine on gas if you stall it at a bad angle and leave the key on while working on the rig.

As for ground, I generally find the frame to be a bad ground. The body and engine are good grounds. The frame is insulated with body mounts, engine mounts, springs shackle bushings, etc.
About the only ground for the frame is through the gears and bearings inside the transfer case, through the U-joints and slipyoke of the front driveshaft, through the gears and bearings of the front axle, through the front coil springs, and finally to the frame.

As for the Holley pump, do you plan to keep a rebuild kit handy for it? Remember to run a regulator, the red pumps are too high of pressure for a carb without one.

 

[eBronc]

..uh, wait a sec.

Relays are good, espically for old, aged and stressed stock eletrical system.

A good trigger source is the "I" terminal on the voltage regulator. Unlike radio or other taps, it only turns on with the ignition in the Run position, not accessory.

The oil pressure safty switch is a good idea. Engine will run without oil pressure only as long as there is fuel in the fuel bowl(s), then stop. Also prevents hydrolocking the engine on gas if you stall it at a bad angle and leave the key on while working on the rig.

As for ground, I generally find the frame to be a bad ground. The body and engine are good grounds. The frame is insulated with body mounts, engine mounts, springs shackle bushings, etc.
About the only ground for the frame is through the gears and bearings inside the transfer case, through the U-joints and slipyoke of the front driveshaft, through the gears and bearings of the front axle, through the front coil springs, and finally to the frame.

As for the Holley pump, do you plan to keep a rebuild kit handy for it? Remember to run a regulator, the red pumps are too high of pressure for a carb without one.

Whoa there, fella. You make some good points, but I've got to respectfully disagree with you on a couple of things.

You may have the Holley "Red" and "Blue" electric fuel pump confused with each other - the "Red" pump is perfect for a carb, and does NOT require a regulator..it's preset to put out around 7 psi. The "Blue" pump puts out around 14 psi, and you really need a regulator if you want to run that one.

If your battery is connected to the frame (like it should be), then the frame is the BEST ground you're going to find on a vehicle. Current shouldn't be flowing through all those components you mentioned at all. It should flow from the battery through the fuse box, through the switches and components in each circuit, then back through the frame to the battery. The frame acts as the "return" half of each circuit, conduting current with little resistance right back to the negative post of the battery.

I have a "Red" pump on my truck to supply the built 351W, and my brother's '32 highboy runs a "Red" pump to supply it's built 350 SBC. The mounting bracket for the pump has a thin rubber insulator, but it's for vibration insulation, not electrical. Be sure and run the black wire from the pump to a good FRAME ground, and you won't have any (electrical) problems with it.

 

[airman]

Is there anyother ideas to interupt a relay than oil pressure switch? I can already see what a pain in the yoohoo putting a tee on the end of the extension and then threading on the sending unit and this new switch. It never stops does it! I like the I terminal from the regulator to switch the relay. I like not going through the firewall one more time.

Is the red fuel pump such a pile that I need to carry a rebuild kit?

 

[Broncobowsher]

OK, I may have confused the red and blue. I though the blue was the street and the red was race. I don’t run them, nor do I ever plan to. I will just stick to my good old reliable run forever Carters.

As for the frame, I will disagree with your disagree. The battery should be grounded to the engine, preferably at the starter. But with the mass of an engine, just about anyplace will do. I prefer the block to a head if I have an equal choice. My battery is actually attached to the transfer case. The starter will actually ground through the transmission so I guess the best place, besides the starter itself, is actually the bellhousing bolt, but nobody seams to do that. The added drop of a couple feet of wire is usually more then the drop through the block would be.

All those insulators are still in effect going between the frame and the engine. There are many cases of burned shifter cables in GM cars from batteries grounded to the body and not the engine.

I installed an old (very old actually) warn winch on the bronco a few years ago. It was grounded through the case. Has one stud and powers in with a single wire. Hooked it all up and it didn’t work, but worked great when bench tested it with jumper cables. After tracing down the voltage drop, I found that the frame had almost no connection to the body/engine. I had to add an old starter cable between the engine and the winch to get it to spin over. Unless someone has done something to electrically connect the frame to the engine or body, the frame is basically insulated.

I have also had problems with other grounds. Try and figure out how a bad ground causes an engine to run rich, only with the headlights on. Runs fine with the headlights off. I figured it out. I know my grounds.

 

[eBronc]

Sure, grounding the battery to the engine block will work. The starter and the engine will run fine. The lights, horn, radio, heater fan, lighter plug and other accesories that are grounded to the BODY won't work very well (if at all) unless there's some type of ground connection between the engine block and the body (there usually is - throttle linkage, clutch linkage - something), and whatever's grounded to the frame (fuel sender, trailer light wiring, really old winches, that type of thing) won't work very well, either. Sometimes there is an unintended conductive path that the current will find and use (current seeks the path of least resistance), like shifter cables, speedometer cables, etc..but the point is, none of those things are DESIGNED to function as a conductor - and if they carry too much current for too long, problems will occur. Shifter cables will heat up and melt the plastic surround, causing sticky shifting.

All that's really needed are a simple ground strap between the frame and the engine block, and one between the body and frame. This will make them all electrically common with the the negative terminal of the battery - whatever it's connected to. Lots of weird problems (like engines that run rich only when the headlights are on, because they're using some other wire as a ground..like the coil or choke wire, maybe)) can be cured for only a few bucks and a few minutes' work.

 

[airman]

are these electric pump sumbersible? Where I would like to mount mine (inside frame rail) looks like it could get wet if I ever crossed a running wash.

thanks for the help and for the record, you have both helped me and I would be blind without your thoughts and experience. I checked my neg battery terminal to the bolt on my fron bumper and I have zero resitance so I must somewhat grounded but even with that being said I'm adding a grounding strap to the frame.

 

[70_Steve]

are these electric pump sumbersible? Where I would like to mount mine (inside frame rail) looks like it could get wet if I ever crossed a running wash.

Unless you mount the fuel pump inside with you, it's gonna get wet. Even in Phoenix it does rain sometimes. ;D

When you buy the fuel pump (I bought the Carter) it will, most likely, come with a wiring diagram. That diagram will include the wiring to a Low Oil Pressure Fuel Cuttoff switch. Seemed like a good idea, so I installed one. I used Holley switch, for what that's worth. It's just a single pole, double throw switch. The Normally Open contact wires to a Run connection, and the Normally Closed contact wires to the Start connection. That way, when you turn the key to Start, the fuel pump runs. When the engine starts and you have oil pressure, and the key in the Run position, the fuel pump also has power.

(Not) To make things more confusing.. I wasn't happy not having the fuel pump run in Key On Engine Off ( ) when I was first starting it. A feature of my POS Carter AFB carb is that it will tend to boil all the gas out of the fuel bowl after being run, then shut down for a while. With the mechanical pump, I would have to crank the engine for a while, untill I filled the fuel bowl again. I wanted to be able to run the pump initially to fill the fuel bowl, then turn the key to Start. I wound up wiring in a Bypass pushbutton, so I could bypass the Oil Pressure Safety switch. I have a hand-drawn diagram at home.

For what it's worth (diving into the big grounding debate) I have my Negative battery cable attached to the engine block. I have a ground strap from the block to the firewall to ground the body, and a big a$$ ground strap from the frame to the block, in case I ever decide to install a winch. My fuel pump(s) ground to the frame.

 

[Skuzzlebutt]

I like the idea of the momentary by pass for pre start priming, when needed.
I would connect the relay to the STA on the alternator so the pump would shut off with the engine stops.

 

[eBronc]

There's more than one way to skin a cat..

are these electric pump sumbersible? Where I would like to mount mine (inside frame rail) looks like it could get wet if I ever crossed a running wash.

thanks for the help and for the record, you have both helped me and I would be blind without your thoughts and experience. I checked my neg battery terminal to the bolt on my fron bumper and I have zero resitance so I must somewhat grounded but even with that being said I'm adding a grounding strap to the frame.

;D Didn't mean to hijack the fuel pump thread with a grounding debate..just thought I'd pass along some info that has come along with experience.

The Holley "Red" pump on my Bronco is mounted to a bracket that places it just behind the rear axle, on the crossmember just in front of the fuel tank. The pump sits over toward the passenger side frame rail, and the fittings are even with the bottom of the stock tank (which has been raised a few inches since I have a 2" body lift and wanted a better departure angle under the tank). It would take at least waist-deep water to submerge the pump, and yes, I'll take it into water that deep (and deeper). Running under water for a few seconds every now and then won't really hurt the pump any more than it would a starter (which is pretty low on most engines and usually gets wet in any stream crossing.)

(Oh yeah..my pump is grounded to the frame.)

 

[Bronco Sport]

I mounted mine on the front edge of the inner fender well and the regulator just below it, with a gauge so I can see it clearly to adjust it. I grounded it to a stud that was used for ground by something else. It works great and have had no issues with it, unlike the old mechanical ones before.

 

[airman]

so the consensus is DO install the low oil pressure switch. I would assume that just wires into the relay coil on the ground side. One more crazy appendage to the engine. I already have the extension for the gauge sending unit. Will the weight of two things on this be too much and break it at the threads?

 

[ASE-73]

While you are at it, install an electric tank switch (assuming you have two tanks). Also, build security (anti-theft) into the relay circuit ... meaning have a hidden switch for the control side of the relay. You can do tricky stuff like convert the cigar lighter so it needs to be depressed (pushed in) to close the control side of the relay back to the ignition switch.

 

[BwoncoHowie]

Re: ..uh, wait a sec.

If your battery is connected to the frame (like it should be), then the frame is the BEST ground you're going to find on a vehicle. Current shouldn't be flowing through all those components you mentioned at all. It should flow from the battery through the fuse box, through the switches and components in each circuit, then back through the frame to the battery. The frame acts as the "return" half of each circuit, conduting current with little resistance right back to the negative post of the battery.

"Should" is a really BIG word when it comes to a bronco frame ground. From the factory mine was not equipped with a good ground to the frame. I dont know how many other eb owners share this in common but, I had to add a ground wire that ties the engine block and the body and the frame all together with the battery. It is better to have a good frame ground wire especially if you have lights, winch, or other electric device mounted to the bumper or frame. So if you plan to ground any electrical item or accessory to the frame, make certain you have an adequate ground connection between the (-) batt and the frame.

As far as switches go how about wiring the fuel pump to the ign. and adding in series a hidden cutout switch that can also act as a theft deterrant.

just some thoughts %) BH

 

[BwoncoHowie]

Sure, grounding the battery to the engine block will work. The starter and the engine will run fine. The lights, horn, radio, heater fan, lighter plug and other accesories that are grounded to the BODY won't work very well (if at all) unless there's some type of ground connection between the engine block and the body (there usually is - throttle linkage, clutch linkage - something), and whatever's grounded to the frame (fuel sender, trailer light wiring, really old winches, that type of thing) won't work very well, either. Sometimes there is an unintended conductive path that the current will find and use (current seeks the path of least resistance), like shifter cables, speedometer cables, etc..but the point is, none of those things are DESIGNED to function as a conductor - and if they carry too much current for too long, problems will occur. Shifter cables will heat up and melt the plastic surround, causing sticky shifting.

All that's really needed are a simple ground strap between the frame and the engine block, and one between the body and frame. This will make them all electrically common with the the negative terminal of the battery - whatever it's connected to. Lots of weird problems (like engines that run rich only when the headlights are on, because they're using some other wire as a ground..like the coil or choke wire, maybe)) can be cured for only a few bucks and a few minutes' work.

Here's an idea that works for me as far as a good ground goes.
The Neg (-) battery post connects to a bolt that goes through the wheel well and is held in place by a nut with washer sandwich on both sides of the sheet metal. I have 3 separate ground wires connecting to that spot, the battery, frame, and engine block.

It helps to remove the paint where the washers make contact and put some wheel bearing grease with graphite in it on the bare metal before tightening the bolt. This will help to retard corrosion in that area where you need to maintain a good connection.