Installation Instructions
Wide Band EFIEs

Install your fuel efficiency device

The EFIE is not intended to be a fuel saver by itself. You should install a device that is designed to get more energy out of the same fuel, such as a hydrogen gas electrolyzer, a fuel vapor production unit, fuel heater, or other device that gets more power out of the same fuel by increasing the efficiency of the petroleum's burn.

Locate the wide band oxygen sensor current wire

The most important point in installing any EFIE, is to correctly identify the wire on the sensor that must be connected to the EFIE circuit. This is also the most common mistake made when an installation is not successful.. In general, the easiest way to locate the correct wire is by use of a wiring diagram. If you don't have a set of wiring diagrams that includes your oxygen sensor wires, then see this article: Wiring Diagrams. Once you think you have found the correct wire, I still recommend that you test it to be sure. The correct wire will often be marked "A/F+", with the other wire in the pair called "A/F-". Often times the wiring diagram will not tell us specifically which wire we need, but will show which wire is paired with which. The 2 current pump wires will always be paired with one another in the diagram, and that's usually all you need to know to identify them.

Please see Wide Band Oxygen Sensors for information on identifying and testing your sensor wires. This article describes how to find the wire you'll need to attach to your Wide Band EFIE without a diagram. You are looking for the "current pump" pair of wires, which should be around 2.7 and 3.0 volts, or 3.0 and 3.3 volts. The wire we need is the one that has the higher voltage of this pair. We will call this the "current return wire", and this is the one that we will connect the EFIE's signal wire to.

Locate 12 volt power and ground

You need to ensure that you have switched power, not power directly from the battery. You don't want the EFIE running 100% of the time.

Most of the fuel efficiency devices need switched power as well, and you can then piggy back onto them. Note that the EFIE draws negligible power. You can attach it to any circuit. The best choice for a voltage source is a fuel efficiency device, such as a Hydrogen generator. That way the EFIE only activates when the fuel efficiency device is turned on. Note that when power is shut off to the EFIE, the signal from the oxygen sensor to the computer is not affected. The EFIE has no affect on this circuit when it's powered off.

Ground can be the vehicle body, engine block or ground from another device. Just make sure that whatever you choose to use for ground has a negligible resistance (less than 10 ohms) when tested against the negative battery terminal of your car.

The Wide Band EFIE:

The wide band EFIE has only power and ground connections, and one output wire for each sensor. Below is a picture of a Dual Wide Band EFIE. It is shown with just the lugs and no wires attached, but the colors indicate which wire color plugs in at each location. The white and blue wires are the output wires, and each of these will be connected to a wide band oxygen sensor's current return wire. Note, if you are installing a dual EFIE and only have one wide band sensor to handle, then only use one of the output wires. Leave the other one disconnected.

The EFIE's signal out wire connects to your wide band sensor's current return wire. Connect the white wire to one wide band sensor's current return wire, and the blue wire to the current return wire of your other sensor. The EFIE signal wire is tapped into the sensor's current return wire. The original path of the current return wire between sensor and ECU is maintained, and the EFIEs signal wire is also connected to that wire, forming a "Y".

The signal out for both outputs is controlled with a single pot. When turned counter-clockwise all the way to the stop, it has almost no effect. When turned clockwise all the way it will add about 1.5 milliamps. This is the full lean position and you should never need to set your EFIE this high. Note: Prior to 25 Aug 09, our Wide Band EFIEs had a range of 0-3 milliamps. We reduced the range to 0-1.5 milliamps, as no vehicles could use more adjustment than this.

I'm sometimes asked about what wire size you should use if you have to extend the EFIE's wires. Well, any wire will do. The power drawn by a Wide Band EFIE is so minimal, that a 30 gauge wire would be plenty. The circuits going to the sensors use even less current. However, 30 gauge wire is not practical because it is so small and fragile, that if you bumped it with a tool, you could break it. We often use 24 or 22 gauge wire. I also prefer stranded wire, because it is less likely to being damaged by moving it around. But again, that's a preference. Solid or stranded wire will both work fine electrically.

Setting the Wide Band EFIE:

I'll start this section with a word of caution. Setting these EFIEs too high can cause your engine to run too lean. Running too lean can cause the valves to overheat and may actually burn them, requiring an expensive engine overhaul. This danger doesn't exist with narrow band EFIEs because the EFIEs are not able to achieve the amount of control that these wide band models have. So you must be careful. If you set this EFIE above 1/2 power, be very careful you do not have any signs of an over-lean condition, such as loss of horsepower at any engine speed.

We should review a little of the basic theory of why we are using an EFIE: When you add a fuel efficiency device, such as an HHO generator, one of the results will be that there is more intake air in the exhaust per amount of fuel. This equates to more oxygen, that the oxygen sensor then detects. The additional oxygen means that the air/fuel ratio appears lean to the computer, and it will react my adding more gas. This causes you to lose some of the gains you should be getting from your fuel efficiency device. The purpose of the EFIE is to counteract this effect. The EFIE makes the signal look richer than it is, causing the computer to lean the mix. The point of this is, that all we are trying to do with the EFIE is to counter the effect caused by your HHO. We're not actually trying to lean the mix. We just don't want the HHO to cause it to run rich.

So take it easy in setting this device on your car. I think you'll find that the correct setting will be between 1/4 and 1/2 power. Some cars will go over 1/2. I've never seen 3/4 yet, but if turns out to be correct for you, please email me and let me know. The thing to do is to start low, and test your mileage. Then raise it a bit and see if you've mileage improves. Continue to test in this way until you get no increase of mileage, or a decrease. Then go back to the last point that increased mileage. That's where you want to be.

Summary:

If you run into trouble or have can't understand these directions, please contact support@fuelsaver-mpg.com. We can use your questions and comments to improve the instructions for others. Also log into our forum at www.fuel-saver.org. We have created a forum specifically for our Wide Band EFIEs, where you can read what others have discovered using these devices, and get help and suggestions for your own project.

Good luck with your project.