DIY EFIE for less than $5.

[cfg83]

csrmel -

Originally Posted by csrmel

im going to leave one last reply as personal closure to this thread.

in my state of florida i dont have emissions testing. i dont even have a cat converter installed on my car right now. just a bypass pipe i made. the cat fetched $125 at a scrap yard. anyways, im not concerned with emissions as i already drive an efficent car. its not like i have a gas guzzling v8 with a choke stuck closed. i know some of you are very concerned with emissions, and will only do fuel economy mods which dont impact youre emissions. i can understand this, espically sence most states in the usa have yearly emissions testing. if i lived in another state which had yearly testing i would not remove my cat or mess with the o2 either. but i live in florida and we have no emissions testing. and besides that fact, i dont really care if my car emits more emissions. im just not converned with it. i would rather get better fuel economy and use less gas than have lower tailpipe emissions. perhaps that is wrong of me but its just how i am.

Ok. That's where you stand. I'm in California, so I have a different context.

in any case, i developed my o2 sensor mod by myself and for my own car. i didnt make it for other people. i just thought that since it seems to work quite good for me then maybe i should share it with you guys and maybe some of you might even give it a try. if you guys dont want to try it thats cool i mean i dont do some of youre mods like the pcv catch can for example. (my crankcase vents are routed to open atmosphere)
its just that going off topic about things that have nothing to do with this got my goat. but thats ok as ill grow some thicker skin and stay on the website. i was actually supprised people send me pm's and emails asking me to stay. kind of hard to argue with that you know....

I think that all Internet forums are subject to thick skins. This site is actually much nicer than others. Also, threads *always* go off topic, that's the nature of the Internet beast. From my POV, once I post a thread, it's fair-game. What's worse is posting a thread and getting NO response .

so anyways, the o2 sensor mod works good atleast for my car. maybe other makes and models of cars this wouldnt work so good on? who knows. i notice that it doesnt take effect right away. seems to take 50-100 miles before it starts working. i dont know whats up with that. perhaps the computer needs time to adjust the long term fuel trims? thats just a shot in the dark as to why. but ive since decreased the resistor value from 1750 to about 1100ohms. this gives the sensor ground a bump in the voltage, and i still dont have a check engine light so i think everything is within the computers parameters. i figure that every couple days or hundred miles im going to slightly decrease the resistor value. today im going to replace the resistor with a potentiometer thats inline with a 500ohm resistor. that was if i set the pot to zero ohms, ill still have 500ohms resistance to avoid sending a 12 signal right through the o2 to the computer. i guess ill keep going down in value untill i either get a check engine light or the engine starts to stumble and miss or ping. im not going to drive it so lean that it misses and pings. thats not worth it.
if anyone actually tries this, give me an email or pm after youve got a couple hundred miles on it and let me know how its working. i would be curious to see what resistor values other cars respond to (if they even respond at all that is). goodluck and look for my next thread dealing with a manual lockup switch for the chrysler a604 ultradrive torque converter.

It's cool that you are adding a potentiometer. That sounds like the logical next step. I'll bet you would enjoy this Internet magazine website :

http://www.autospeed.com/

It has *lots* of mods that trick the ECU/PCM.

CarloSW2

[Freedom_man]

Originally Posted by MY02WRX

If you want to save fuel, your best bet is to find a chip that includes a data port for a laptop, you should have a wideband o2, a laptop, and datalog in real time the inputs of all your sensors, and tune your ecu with your laptop accordingly.

Try a megasquirt II home build injection controller I think you can control ignition with it too. I know that you can hook it up to your PDA, Laptop, and/or desktop if you have LONG wires or a desktop in the garage.

Something you can look into.

[Freedom_man]

Originally Posted by MY02WRX

That doesn't make sense to me, on initial start up yes you would be dumping fuel, however, the computer should lean your fueling out to create heat, running rich will create your engine to run cooler, running lean creates alot! of heat! As far as everything I've read and monitoring a/f after initial start up the engine leans out to create heat, and thus warm the engine up quicker. Post cat o2's mostly monitor cat heat, which would be a lean situation, running rich will not cause near the heat as running lean will.

The reason you car dumps in loads of fuel while cold on start up it because the fuel does not atomize well while cold so it adds more so it can get the vapors which is the only thing that burns in the cylinder anyways.

If you lean it out while cold you may not get enough vaporization to start the car well. If you want to start out lean then you might try heating the intake manifold with something like a hair dryer, block heater, heat gun, etc.

Most FI cars I have seen have a therm sensor as part of the fuel injection control. Once the coolant warms up the car starts leaning out. Some cars like the late 80's early 90's 626 and ford probes had problems if you got an air bubble stuck at the heat sensor. I've had that problem.

[Freedom_man]

Originally Posted by Erik

What about the VX lean burn mode? Is that harming the engine?

I would like to lean out my carburated 87 civic, but I too am concerned about engine damage.

I can tell that the engine sometimes runs a little richer and other times leaner (I suppose the crude electronic control box is trying to do its job). Sometimes when fully warm, I get a little spark knock climbing a hill on my way to/from work, other times, I get no spark knock on the same hill, even when I purposely lug the engine a little and when it the same outside temp and same engine temp.

By the way, is there anyone out here that knows how the honda feedback carbs richen/lean the mixture? It is not electronic (I have rebuilt the carb) so it must be a vacuum bleed to lean it out or somehow keeping the power valve from richening the mixture via a vacuum line.

If you want to lean it out without blowing the head from over heating try a water/steam injection system. There are plans online for home built systems that are vacuum operated. The neatest one I saw includes a one way check valve and a two wrap around the exhaust water heater.

The vacuum reduces the boiling point so the water does not have to be as hot and when compressed will re-condense under pressure and then boil again when the fuel burns absorbing the heat generated from a lean burn the bonus is that you not only get the fuel burn pressure but steam pressure to push your piston. When build correctly you will get cleaner cylinders, more power/torque, and better mpg.

The old muscle car guys used to run water most of the year and water alcohol mixes in the winter to prevent freezing.

[brad5428]

wher can i find the info/diagram for the diy efie for less than 5$?
thanks brad

[speedofmouth]

I just joined, does anyone have the plans & diag. for this. It would be greatly appreciated. Thanks

[ZugyNA]

Originally Posted by csrmel

i dont do some of youre mods like the pcv catch can for example. (my crankcase vents are routed to open atmosphere)

Some PCV jars (a Condensator) can actually provide gains in mpg due to cleaning up and utilizing the PCV flow as a combustion enhancer.

Also it might be possible to increase mpg by also setting up a minor amount of vacuum in the crankcase 4-5" HG (?) which tends to reduce windage losses...and increases blowby slightly to use the crankcase as a vapor carb?

[GasSavers_RoadWarrior]

Pulling a crankcase vacuum is meant to improve ring seal, so blowby should be reduced.

If you actually want to crack your PCV products rather than collect them you need a catalytically active filter medium with a large amount of area. Silica gel has been postulated, but I think that this was under the misunderstanding that silica gel was the active medium in some industrial catalysts whereas it is usually just the substrate to support the catalyst. i.e. the silica gel granules in question will be coated with something else. The best options appear to be either copper plated ball bearings, or copper pan scrubbers. Steel does have catalytic activity, but only at higher temperatures, and it will tend to rust out with moisture. Copper may oxidise or turn into a carbonate, but it's compounds are still catalytically active, so there's no need to change it out if it goes green or blue. If you can figure a way to introduce a minor amount of steam into the PCV jar, then even the heavier crap will get hydrocracked into useful fuel fractions.

[sargon]

Originally Posted by Erik

What about the VX lean burn mode? Is that harming the engine?

I would like to lean out my carburated 87 civic, but I too am concerned about engine damage.

As has been hinted at a bunch of times by very knowledgeable people, there is no point in blindly leaning out the fuel mixture. EFIE's (electronic fuel injection enhancer), which lean out the fuel, are designed to be used in conjuction with other fuel saving devices, such as a hydrogen generator. It is required for the correct operation of such devices, as extra oxygen will always be present in the exhaust, causing a very incorrect a/f ratio. The EFIE adjusts the o2 sensor voltage level by adding a precise offset voltage to the signal corresponding to the more or less fixed amount of extra oxygen present in the system. This is all in an attempt to regain the proper 14.7:1 a/f ratio.

That being said, an EFIE cannot be setup with a simple resistor voltage divider. The battery voltage is connected to the alternator which does not provide a stable voltage (varies over time), thus your offset changes with the battery voltage. For best operation you need an electronic circuit that provides a rock solid voltage offset that doesn't vary with time, temperature or supply voltage.

Now, with all of that being said, these hydrogen hybrid systems should be using fuel mixture controllers to properly adjust all appropriate computer signals.

[itjstagame]

So seriously where'd the diagram go? I was thinking about this today too. I was thinking about maybe a battery inline with resistors to ramp up voltage but the more I thought about it any resistors would affect the O2 as well, I'm really not sure how to do what I want.

The thought of increasing voltage on the grounding seems like it would work but I just have a 3 wire O2, so ground must be shared with my O2 heater and I'm not sure I want to mess with that. I can certainly reduce 12V to .07V if I want to but not sure how to have a circuit with .07V and one with .45v and get to .52V. Hooking the .45V just shunts voltage to the .07V as a ground but seems to still read .45V in the middle (where ECU is conencted to).