16 gauge steel fuel pump mounting bracket with rubber insulating washers (both sides) for noise reduction. Fuel Pump Installation This article appeared in The British V8 Newsletter - Volume X, Issue 1 - January 2002 by: Dan Masters Depending on the power level of your new engine, you may be able to get by with the stock fuel pump. Chances are, you will want to move up to a higher capacity pump - what good are all those horses if you can't keep them fed? The fuel pump on my bone stock MGB GT failed last month, so I decided to replace it with the Holley I had on hand, which I had been saving to use when I finally got around to doing the V8 swap.
I could have installed the new pump in the same location, using the same mounting details, as the factory installation, but I really didn't like that option. After a little head scratching, I came up with the scheme shown in the photos below. When I finally get around to doing the engine swap, I will also redo the fuel tank location (to allow dual exhaust), and reroute the fuel lines.
For now, though, this installation required no modifications at all to the fuel lines - just slipped new fuel lines over the old hard lines, routed them to the new pump, and clamped the lines in place using standard hose clamps. I'm not saying this is the best way to install a pump, but it works for me. If you use a larger pump, I think this method will have definite advantages over most other locations. There is plenty of room for a large pump and all the fittings required to feed larger diameter fuel lines. If you have the rear suspension out of the car, and have the car up on jack-stands, installing the pump is about as easy as it gets. If you're installing it the way I did, with everything in place (except the rear wheel, which I did remove), here are a couple of tips you might find useful: 1) Make the holes in the battery box first, then hold the mounting plate up to the box and scribe locating marks for the matching holes in the plate. It is hard to get to the battery box brackets, so it is very easy to wind up with the holes slightly off from where you intended.
The mounting plate can be drilled on your workbench, with a much higher degree of accuracy. By making the bracket holes first, you can ensure a perfect match. 2) If you can, use a hole punch, rather than a drill to make the holes in the battery box. There isn't a lot of room for an electric drill.
I have a Roper-Whitney hand punch that works very well for this. In fact, this punch works so well that I use it to punch holes in sheet metal even when I do have perfect access for a drill. The punch makes a clean, round hole with no burrs.
Enjoying this article? Our magazine is funded through the generous support of readers like you! The rise of the roman empire pdf. To contribute to our operating budget,. (Suggested contribution is twenty bucks per year. Feel free to give more!) 3) Carefully check the location of the pump and the routing of the new fuel lines, to ensure there is no interference with the rear suspension. You certainly don't want to wear a hole in a fuel line, or crack the pump housing.
There are a few options for wiring the pump: The first option is to just wire the pump to the existing wires. I used a two-pin connector, but that isn't necessary. Simple splices will do, but it will be harder to remove the pump for repairs if needed. A second option is to use a relay, wired as described in the May issue article on a custom wiring system. A revised schematic for this is shown below, modified to work without the relay panel as described in that article.
See the May issue for a description of the circuit operation. Two other options are shown in the diagrams above.
The diagram in the center uses a relay, but has no provision for manual switching. Any time the ignition switch is on, the fuel pump is also on. Missing from this circuit is the inertia switch. I strongly recommend using an inertia switch because without one the fuel pump might continue to operate following an accident, and could pump a lot of gas onto the ground if a fuel line ruptures. The circuit on the right describes the use of an 'ON - OFF' control switch, along with an inertia switch, but no relay.
When the switch is in the 'ON' position, the pump turns on and off with the ignition key. When the switch is in the 'OFF' position, the pump will not operate, but the warning buzzer will sound to remind you that the switch is off. This switch provides a bit of theft protection. If you use this switch, it should be mounted out of sight, but within easy reach of the driver. The buzzer serves to remind you to reset the switch before driving off and running out of fuel. If the switch is off, the buzzer will sound as soon as you turn on the ignition (don't ask me how many times I've heard the buzzer in my car - I'm more than just a bit forgetful).
Except as shown, the wiring should be 14 gauge. You could probably get by with using 14 gauge wire for all of the wiring, but you should use a pump that draws no more than a 10 amps if you use the smaller wire.
The inertia switch should also be mounted where it's easy to reach by the driver, as you want to be able to reset it without stopping, should it operated from the shock of hitting a pothole in the road. In general, these inertia switched are not prone to mis-operation, but why take a chance. If you use the wiring scheme presented on the previous page, the warning will sound if the inertia switch should operate. If the switch is in easy reach, you can simply reset it on the run, and not miss a lick. Disclaimer: This page was researched and written by Dan Masters. Views expressed are those of the author, and are provided without warrantee or guarantee. Apply at your own risk.
Bodywork
Oil Pressure Switches The Key! Their are many types of oil pressure switches, most common ones are normally closed. These WON'T WORK. These common ones will not work as we need a Normally OPEN switch that closes when oil pressure crosses some threshold. In poking around the web I found the site. The Wells site has listings for many different style of senders. The main thing we are looking for is 'NORMALLY OPEN' or 'NO', or a combination switch that has both a NO (Normally Open) and a NC (Normally Closed).
For most common applications the 2 Prong PS113/PS114 or 3 Prong PS118/PS122 will work. These are available in either 1/8' NPT or 1/4' NPT so be sure what you order. They are available in long reach as well as a few other threads and style of connectors and fittings. Check out the Wells site for selection.
Both the PS113/PS114 and PS118/PS122 have standard spade connectors that can save some money if you don't want to spend on the waterproof harness plug. The 3 Prong PS118/PS122 can replace the PS113/PS114 as it only has an additional circuit for a warning light. Otherwise they are the same. My preference would be to get the harness for the PS118/PS122, which is a 3 wire unit but can be used on the 2 terminal types.
If needed later if you ever want a warning light, it's ready to go with the third wire. Inertia Switches This is almost always overlooked when doing an electric fuel pump, most OEM vehicles have these in some obscure place.
Electric Fuel Pump Install Diagram 2 Pumps
You should have one too, but make it accessible, and if in a race car even more so. Not sure if these would work in a off road vehicle, but I'm mainly talking road cars here. I have picked up a couple of different types of these, but now falling back on the more common OEM parts. Has a few types, but hit Summit, eBay as they seem to have lower prices. These are not cheap parts, but I'll bet the cost is mostly going towards insurance if one fails. Lastly look for the inertia switches that come with a pigtail or harness. Trying to get OEM style connectors can be a pain in the a$$ and costly so make sure you get one that comes with the wires!
Diodes WTF is a Diode?? WTF is a Diode you ask (skip if you already know)??? Simplest way to describe it is a diode is one way valve for electricity.
We can use one to help with starting where we have no oil pressure built up yet. This can be an optional part. If you are running a car with a carburetor you may get away without this part of the circuit. If you car builds oil pressure fast and you have fuel in the float bowls you are good. EFI cars may be a different story. If you have an EFI car your ECU may control the fuel pump, but if going the manual route use the diode to turn on the pump once you hit the start button (or key).
Diodes are inexpensive, the part numbers listed are very common. Typically diodes have 2 leads one will have a white band next to it.
Positive voltage will flow from the non-marked end towards the white band end. It will not flow in reverse. In our case we want voltage to flow to the relay when the starter switch is closed, bypassing all the safety switches so the car can start. Once the car starts, you will have oil pressure and the pressure switch will close completing the circuit and energizing the the fuel pump.
The trick is we do not want the voltage from the ignition circuit to get into the starter circuit, if it did your cars starter would never stop working. That's not what we want. Low Oil Pressure Indicator You can get creative here, I have used a couple of different style of truck side markers, and may work depending on where they are mounted.
Check out some examples for some example, look for ones that are surface mount. If using LED make sure that they are bright and you can see them in daylight. Lastly some require a special connector ensure that it's included. If you are not sure head out to the Autozone, Pep Boys, etc and rummage through their trailering section you will find something that will work.
![Wiring Wiring](/uploads/1/2/3/7/123751908/633109402.jpg)
Basic Safe Electric Fuel Pump Wiring Diagram This is the basic wiring diagram for SAFE electric fuel pump wiring. The diagram is color coded per circuit and only a few things may need to be said. Fuel pump wiring for the RED circuit is generally going to carry a much higher current than the relay. So use a larger gauge wire for lower voltage drop.
For big pumps try 12 gauge, for smaller smaller 14 gauge. You want to limit voltage drop by using a heavy gauge wire. Check out the here to help with selecting the right gauge wire For relays and related switches 16 or 18 gauge would be OK. The fuel pump ground should be the same gauge as the positive lead if not obvious. Basic Operation Ignition is turned on, but no fuel pump due to the Normally Open pressure switch. Hopefully the inertial switch is OK an you are not upside down.
If the inertia switch is OK, it's normally closed and will break the circuit in the event of a catastrophe. Now you hit the start button, the voltage will pass through the diode to the relay, and the relay will close the circuit starting the fuel pump. Hopefully your car starts, and ultimately builds oil pressure which will close the oil pressure switch.
This will enabling and sustain the fuel pump relay in the on position. Now you can drive away! Once locked on by the ignition circuit the diode will BLOCK voltage back to the starter circuit. Turing off the ignition will remove voltage from the relay, and shut off the pump.
Oil pressure will be zero so the oil pressure switch will also be open circuit again. Something bad happens You are in a race and blow your engine and have zero oil pressure, fuel pump will stop You are in a race and end up in a smash up, inertia swich will open, fuel pump will stop Replace 'You are in a race' with 'I'm driving to work', or other colorful phrases. You get the idea.
That's about it. It's not hard to make it safe and reliable. See below if you want the deluxe version! Deluxe Electric Fuel Pump Circuit with Warning Light Deluxe Fuel Pump Wiring with Blown Engine Light circuit above This circuit is similar to the basic wiring diagram the same except you use a different pressure switch and add a warning light that directly watches the oil pressure. The 3 Terminal pressure switch has an extra terminal that can be used exactly like the Oil Pressure warning Light. The switch actually is 2 Switches in one.
One will be used exactly like the basic wiring diagram (Terminal 1 and 3). The extra terminal (Terminal 2) will close to ground (via engine block typically and body of the switch) when pressure is lower than a couple of PSI, and will open when the engine is making oil pressure just like the old idiot lights! This can be connected to a bulb or side marker in my examples that will shine in the face of the driver.
This won't stop your motor from disaster, but will limit how bad the damage is. Also, Don't say 'I have gauges and always check.'
, what I have to say about that 'if you're watching gauges you ain't driving hard enough' Otherwise the circuit is very similar. Conclusion This is a simple guide to safer wiring for your electric fuel pump. Spend some time wiring things up right and in the event of a problem it can save you a world of hurt (or fire).
Get your projects done and - Happy and SAFE motoring!
This video is about how to install a new Airtex fuel pump module into some GM applications that will require you to install a new wiring connection. Airtex is committed to providing the most up-to-date, in-depth fuel pump replacement information that professional technicians need to diagnose, repair and install today's complex fuel delivery systems.
Airtex is the only U.S. Automotive aftermarket manufacturer that designs and builds electrical AND mechanical fuel delivery system components, including modular reservoir assemblies, electric fuel pumps, mechanical fuel pumps and in-tank sender and hanger assemblies, for a full range of car, truck, fleet and specialty vehicles.
A Fuel pump relay is a setup used in automobiles to maintain a consistent voltage supply to the engine. This consistency ensures a steady flow of fuel to the engine.
An automobile can have a long life if the engine receives consistent flow of fuel and air, especially during high speed driving. Thus, installing a fuel pump relay will increase the life of your vehicle. Step by Step Procedure Step 1 – Prepare the Vehicle The power supply form the vehicle’s battery needs to be terminated as a precautionary measure for this job. It is enough if you disconnect the negative terminal of your car’s battery alone; however, it is safer to disconnect the positive terminal as well.
Step 2 – Check the Engine Unscrew the hood portion of the fuse box in your car’s engine compartment. Most cars may contain a diagram showing the position of fuses and relays on the lid or on the side wall of the fuse box. See if the engine has a fuel pump relay or not (the fuel pump relay is a cube shape connected like an electric plug). If you cannot locate the relay get the help of your usual mechanic.
If you do not have a relay directly go to the fourth step. Step 3 – Remove Old Relay If there is a worn out old relay, remove it with a flat head screwdriver. Step 4 – Purchase the Correct Relay Go to the automobile spares outlet or the spares outlet of your car’s manufacturer and purchase the correct fuel pump relay for your car. If you have the removed relay, you can use it as a sample. Step 5 – Preparing to Install If you did not have a relay at all, you have to do the wiring as mentioned in this step, else you may move directly to the sixth step.
For wiring, remove the hose in the fuel tank and lift the valve off. Remove the wiring harness by moving the locking latch down. Attach a connector to the cable of the car’s battery and connect the 8-ga wire to it. Connect the other end of the 8-ga wire to the 30-amp fuse holder.
Set this wire along with the bundle of wires along the firewall with zip ties. Insert the wire through a hole in the driver’s side of the firewall. Run the wire under the carpeting and bring it to the fuel pump housing side. Join the wire to the 87 terminal of the relay.
Step 6 – Connect the Relay Join the black wire from the fuel pump to the 30 terminal of the relay and the black wire from the wiring harness to the 86 terminal of the relay. Join one more wire to the 85 terminal of the relay which acts as the ground wire. Screw the relay to the body tightly. Step 7 – Check Connect the cables to the battery of the car and check your work by starting the engine.
Oil Pressure Switches The Key! Their are many types of oil pressure switches, most common ones are normally closed. These WON'T WORK.
These common ones will not work as we need a Normally OPEN switch that closes when oil pressure crosses some threshold. In poking around the web I found the site.
The Wells site has listings for many different style of senders. The main thing we are looking for is 'NORMALLY OPEN' or 'NO', or a combination switch that has both a NO (Normally Open) and a NC (Normally Closed). For most common applications the 2 Prong PS113/PS114 or 3 Prong PS118/PS122 will work. These are available in either 1/8' NPT or 1/4' NPT so be sure what you order.
![Diagram Diagram](/uploads/1/2/3/7/123751908/220149184.jpg)
They are available in long reach as well as a few other threads and style of connectors and fittings. Check out the Wells site for selection.
Both the PS113/PS114 and PS118/PS122 have standard spade connectors that can save some money if you don't want to spend on the waterproof harness plug. The 3 Prong PS118/PS122 can replace the PS113/PS114 as it only has an additional circuit for a warning light. Otherwise they are the same. My preference would be to get the harness for the PS118/PS122, which is a 3 wire unit but can be used on the 2 terminal types. If needed later if you ever want a warning light, it's ready to go with the third wire.
Inertia Switches This is almost always overlooked when doing an electric fuel pump, most OEM vehicles have these in some obscure place. You should have one too, but make it accessible, and if in a race car even more so. Not sure if these would work in a off road vehicle, but I'm mainly talking road cars here. I have picked up a couple of different types of these, but now falling back on the more common OEM parts. Has a few types, but hit Summit, eBay as they seem to have lower prices.
These are not cheap parts, but I'll bet the cost is mostly going towards insurance if one fails. Lastly look for the inertia switches that come with a pigtail or harness. Trying to get OEM style connectors can be a pain in the a$$ and costly so make sure you get one that comes with the wires! Diodes WTF is a Diode?? WTF is a Diode you ask (skip if you already know)???
Simplest way to describe it is a diode is one way valve for electricity. We can use one to help with starting where we have no oil pressure built up yet. This can be an optional part. If you are running a car with a carburetor you may get away without this part of the circuit.
If you car builds oil pressure fast and you have fuel in the float bowls you are good. EFI cars may be a different story. If you have an EFI car your ECU may control the fuel pump, but if going the manual route use the diode to turn on the pump once you hit the start button (or key). Diodes are inexpensive, the part numbers listed are very common. Typically diodes have 2 leads one will have a white band next to it. Positive voltage will flow from the non-marked end towards the white band end.
It will not flow in reverse. In our case we want voltage to flow to the relay when the starter switch is closed, bypassing all the safety switches so the car can start.
Once the car starts, you will have oil pressure and the pressure switch will close completing the circuit and energizing the the fuel pump. The trick is we do not want the voltage from the ignition circuit to get into the starter circuit, if it did your cars starter would never stop working.
That's not what we want. Low Oil Pressure Indicator You can get creative here, I have used a couple of different style of truck side markers, and may work depending on where they are mounted. Check out some examples for some example, look for ones that are surface mount. If using LED make sure that they are bright and you can see them in daylight.
Lastly some require a special connector ensure that it's included. If you are not sure head out to the Autozone, Pep Boys, etc and rummage through their trailering section you will find something that will work. Basic Safe Electric Fuel Pump Wiring Diagram This is the basic wiring diagram for SAFE electric fuel pump wiring. The diagram is color coded per circuit and only a few things may need to be said. Fuel pump wiring for the RED circuit is generally going to carry a much higher current than the relay. So use a larger gauge wire for lower voltage drop. For big pumps try 12 gauge, for smaller smaller 14 gauge.
You want to limit voltage drop by using a heavy gauge wire. Check out the here to help with selecting the right gauge wire For relays and related switches 16 or 18 gauge would be OK. The fuel pump ground should be the same gauge as the positive lead if not obvious. Basic Operation Ignition is turned on, but no fuel pump due to the Normally Open pressure switch.
![Pump Pump](/uploads/1/2/3/7/123751908/190821254.jpg)
Hopefully the inertial switch is OK an you are not upside down. If the inertia switch is OK, it's normally closed and will break the circuit in the event of a catastrophe. Now you hit the start button, the voltage will pass through the diode to the relay, and the relay will close the circuit starting the fuel pump. Hopefully your car starts, and ultimately builds oil pressure which will close the oil pressure switch. This will enabling and sustain the fuel pump relay in the on position.
Now you can drive away! Once locked on by the ignition circuit the diode will BLOCK voltage back to the starter circuit.
Turing off the ignition will remove voltage from the relay, and shut off the pump. Oil pressure will be zero so the oil pressure switch will also be open circuit again. Something bad happens You are in a race and blow your engine and have zero oil pressure, fuel pump will stop You are in a race and end up in a smash up, inertia swich will open, fuel pump will stop Replace 'You are in a race' with 'I'm driving to work', or other colorful phrases. You get the idea. That's about it. It's not hard to make it safe and reliable.
See below if you want the deluxe version! Deluxe Electric Fuel Pump Circuit with Warning Light Deluxe Fuel Pump Wiring with Blown Engine Light circuit above This circuit is similar to the basic wiring diagram the same except you use a different pressure switch and add a warning light that directly watches the oil pressure. The 3 Terminal pressure switch has an extra terminal that can be used exactly like the Oil Pressure warning Light. The switch actually is 2 Switches in one. One will be used exactly like the basic wiring diagram (Terminal 1 and 3). The extra terminal (Terminal 2) will close to ground (via engine block typically and body of the switch) when pressure is lower than a couple of PSI, and will open when the engine is making oil pressure just like the old idiot lights! This can be connected to a bulb or side marker in my examples that will shine in the face of the driver.
This won't stop your motor from disaster, but will limit how bad the damage is. Also, Don't say 'I have gauges and always check.' , what I have to say about that 'if you're watching gauges you ain't driving hard enough' Otherwise the circuit is very similar. Conclusion This is a simple guide to safer wiring for your electric fuel pump. Spend some time wiring things up right and in the event of a problem it can save you a world of hurt (or fire).
Get your projects done and - Happy and SAFE motoring!