FAQ

I have a [make/model/year] car and have added a [brand/model] electrolyser. What kind of EFIE do I need? The first thing to do is to read What Do I Need To Know About My Oxygen Sensor?. This will help you obtain the information you need to answer this question. All you really need to know is the type of sensors you have and the quantity. Most American made cars use narrow band sensors only. Japanese and German cars after about 2000 or so start using wide band sensors. If you have any doubt about what you have, you can have us look it up for you by filling out our Sensor Request Form.

What is the difference between your different EFIE models? This is covered in detail in New EFIE Product Lineup.

Is it easy to install an EFIE? How do you do it? The installation instructions for our EFIE models are available online. Please see EFIE Installation Instructions. You can then review the entire process and see for yourself if you think it is something you would like to tackle.

How can I get support for my EFIE? Your first action would be to review this FAQ to see if your question is answered here. You would probably also want to search at our support forum at www.fuelsaver-mpg.com to see if your question has come up before. These are the quickest ways to get your question resolved. However, if these do not get the job done, you can post your question in the EFIE Support section at the forum, or email us at support@fuelsaver-mpg.com.

Do I need a MAP Enhancer as well as an EFIE? Usually, no. In most cases, just the EFIEs will do the job. However, in some cases more is needed to get the results. But this is rare, and we recommend just purchasing and installing EFIEs to begin with. If you think you need a MAP/MAF enhancer as well, then we recommend reviewing the HHO System Debug Checklist. There are a number of things to check before going to the expense of adding another component, and the checklist will guide you on what to check and in which order. If you get to the bottom of that checklist and find that you need a MAP/MAF Enhancer, then is the time to purchase one.

My EFIE didn't come with instructions. How do I install it? The instructions are posted online and can be found here: EFIE Installation Instructions. This is an index page, that has links to the instructions for all of our products. Just find the picture of your specific EFIE and click on it to get your instructions.

I ordered my EFIE but the Post Office says you haven't shipped it yet. What's going on? We ship all products within 2 days of receiving the order, and almost always within 1 day. If there is some problem with your order, that makes this impossible, we will contact you about it. This almost never occurs. However, the US Postal Service never shows tracking information for international shipments and sometimes doesn't update their tracking on domestic shipments either. In these cases you will get the following message if you try to track your package on the USPS website: "The U.S. Postal Service was electronically notified by the shipper on to expect your package for mailing." It makes it appear the shipment hasn't gone out yet. Usually there will be no change to the tracking until the package actually arrives. I like USPS service in general, but its tracking services are weak.

I installed my EFIE but I'm not getting correct readings. Getting incorrect readings can have 2 possible causes. The EFIE can be faulty, or it is installed incorrectly (possibly on the wrong type of sensor). Almost always "defective" EFIEs sent back to us are actually working perfectly. And while we're happy to test them and verify them for you, it wastes your time waiting for the shipping both ways to then find out that the fault is really an installation error. Almost always the error is in the installation, and the most common errors are installing the EFIE on an incorrect type of sensor (narrow band EFIE on a wide band sensor), or the EFIE was installed on on the wrong wire, sometimes from a wire from a completely different sensor. The thing to do is to go over the instructions carefully, and make sure you have identified the correct wire, and to test the wire for correctness (also covered in the instructions). But make no mistake, do not let yourself flounder with this. We will help you get it resolved. Contact us at support@fuelsaver-mpg.com, and we'll make sure whatever is going on gets resolved.

I'm getting a "Check Engine Light". What does that mean? A check engine light (CEL) means that something is running outside the normal parameters that your computer expects to see. If you get a CEL after installing an EFIE, then either the installation is faulty or the EFIE is set too high. You should probably turn the EFIE down (counter clockwise) to a very low setting and see if the engine light goes away. If it does, then you can raise the setting in increments watching for the CEL to come back. In this way you'll eventually discover the highest setting your vehicle's computer will tolerate. If the light won't go out this way, it may just need to be reset in the computer. The ideal tool to have is a code reader which you can now get here. With this tool you can find out what the code is, and you can also reset the code, which makes the CEL go out. Note that if you are unable to cure your code with these procedures, then you must strongly suspect that the EFIE was installed incorrectly or on an incorrect wire.

I installed my EFIE but I'm not getting a mileage increase. With modern HHO electrolyzers and EFIEs there is really no excuse for not getting a 30% - 50% increase in mileage. If you are getting below 25%, you must assume that something is wrong, and if corrected will give you mileage results of 30% or more. Some people have gotten over 100% improvement (but this isn't the norm). We have written up an HHO System Debug Checklist, to help you when you are not seeing the results you expect. This document covers the steps, in order, to check to make your installation successful.

My EFIE is making a loud clicking noise. If you hear your EFIE clicking then turn it off or remove power right away before it's damaged. This sound is the relay inside the EFIE clicking on and off rapidly. We have seen this where the input voltage to the EFIE is severely non-standard in some way. For instance powering the EFIE from the output of a PWM has caused this. A PWM pulses the power to the EFIE which expects to see a 12 volt DC signal. Now an EFIE can easily run from about 9 volts up to about 30 volts, but it expects DC. A PWM is A/C in that it pulses between 0 and 12 volts rapidly. Another time we've seen this was where the EFIE was powered from a battery charger. The output of the charger was so dirty that it also caused the relay inside the EFIE to click on and off. The clicking will go away by providing the EFIE a good clean 12 volts from the car's electrical system.

Do I need a MAF or a MAP enhancer also? Maybe. This is covered in the HHO System Debug Checklist. If you aren't getting the mileage results you expect, there are quite a few things to test before turning to a MAF or MAP adjuster. But some vehicles do need these, along with EFIE(s) to do the job. The thing to do is to do the checklist in order so that the most easily (and cheaply) things can be taken care of first. If these don't resolve the situation, later in the checklist we recommend installing a MAF/MAP handler. As a note, most vehicles can use a homemade MAP/MAF handler that costs a few dollars to make. See A Simple MAF/MAP Enhancer for details. However, some vehicles have MAP or MAFs that give a frequency signal, and these require a special device to alter these frequencies. We will soon have this available for you in our online store.

I can't find my sensor's signal wire. This is covered in detail in the instructions for installing your EFIE. See EFIE Installation Instructions for your particular model. It can be a little tricky, particularly the first time you do one of these, but it gets simple after that. In each case you only have to find one wire for each sensor. If you don't have a wiring diagram, then see this article: Wiring Diagrams. You can also go to the sensor itself and measure each wire individually and find out which is which that way. The details are covered in the instructions. But one way or another, you are only trying to identify one wire for each sensor, and if you can't get it from the instructions, then get on over to our support forum for some help.

Can I return or exchange my EFIE? Most certainly. We have often sold Single EFIEs to folks who later find they have 2 sensors. Or narrow band EFIEs to people who find they have wide band sensors. Some people just change their mind. It's OK to return an unused EFIE for exchange on another device, or to get your money back. We have a very relaxed return policy. Our primary interest is to see that you get the device you need to be successful with your project.

What if I have a question that isn't answered here? You have a few options. Come to our support forum and post your question there. There are many knowledgeable people in our user community. You can also contact us by email at support@fuelsaver-mpg.com. We try to keep support limited to email and forum traffic, but if you aren't able to resolve your question in any other way, then you can also call us. For our number, please see our online store's contact page.