How to build a low cost EFIE
 

I know there is another thread about this same issue, but all the information had been removed by the original poster so since I found it on the internet I thought I'd post a link so anyone who wants to give it a try can benefit. The cost should be under $10.

https://www.youtube.com/watch?v=PEHJ9te7gvk

I thought I'd update this thread. I have made one of the EFIE's, but haven't installed it on the car yet. I'll be using my 505K mile Escort for experimenting!!!! I did put a battery in it and tested to see how much I would be able to adjust the 02 sensor voltage and it gave me 0.0-0.54volts of adjustment so I should be able to lean out the mixture a little bit after doing a little testing to see where the voltage normally runs. I'll just have to be careful and not over do it. I'll start out small and work my way up until it acts like I'm getting in the detonation/danger zone then I'll lower the voltage back down. Looks like it's going to be a while before I get to do the initial testing and installation of the EFIE since we are still getting snow and having lots of weather that's colder than normal for us this time of year.

Don't test it on the 505K mile car! You have to see how long that car will last without any unnatural influences... :D

I second that!

I've got to try it on something and all the other cars are in much better condition with the exception of my wifes '87 Chevy Celebrity and she's against the idea of trying it on her car. I'm not sure, but I suspect if I get it too lean the ECU will kick it into open loop just as it does when the 02 sensor goes bad.

the thing is with a false o2 reading the ECU may never know that it's too lean. I've wanted to mess with this, but i'm putting it off till i have a way of checking exhaust temp.

wouldn't the knock sensor be the safety for that? I would think that the knock sensor would protect the motor and the ecu would richen up the mixture to keep from getting detonation.....I think......maybe

That's exactly the point of doing this mod.

Way to make me sound like a dumbass.

I was replying to this:
"I suspect if I get it too lean the ECU will kick it into open loop just as it does when the 02 sensor goes bad."
I have little faith that this will happen before the point of damage.

The EFIE has been installed now for just over 500 miles. The first fill up after installing looked terrible, (176.2 miles on 5.301 gallons or 33.23 MPG, worst fill up in my gas log) but I think I may have been turning the EFIE on before the car went into closed loop and may have been causing it to stay in open loop. As usual I am still topping the tank off and filling before the tank gets to the half way point. The last fill looked better than it has in months (197.9 miles on 4.908 gallon or 40.32 MPG). This still isn't as good as it was doing prior to changing the timing belt last summer, but it is a great improvement. I never did figure out why the mileage dropped after the timing belt change, but that's a different story. The car seems to be running fine without any signs of detonation and I think I still have a quite a bit of adjusting to do to the EFIE before I get to the maximum I can add, but I'm trying to move slowly so if there's any negative effects I know about what the maximum voltage is I can add to the 02 signal. The last tank was adding 125mA to the signal, when I filled the tank up I increased it to 150mA and according to the fuel gauge looks like the mileage has increase more, but sometimes this fuel gauge acts kind of crazy so who knows. I've been keeping a digital multimeter hooked up to the pre EFIE signal so I can monitor it to make sure the signal isn't running extremely lean for long periods of time, but I've also ordered an a/f gauge to hook up so I can see where it runs.

I'm also planning to put a hydrogen generator on it as soon as I can come up with the materials and time, hoping that even if the hydrogen doesn't help mileage it will allow me to lean it out further.

please get a exhaust temperature gauge

I've given that some thought, but I've also been researching the internet trying to find out what the maximum the exhaust gas temperature should run and can't find it. Do you know? I have also thought of just buying a head temperature sensor. Do you think that would give enough feedback to let me know if I was getting any damage? What would be the maximum head temperature? I read one article that recommended both, because they said that after a certain point when leaning the a/f mixture the exhaust gases would begin to cool, but the head temperature would go up and that was a sure sign of detonation. I've already got a water temperature, oil presure, and amp gauge in it and don't know where I'm going to put more gauges.

In my humble opinion, operators of water cooled normally aspirated (non-turbo) engines don't need to worry about going too lean if they pay careful attention to listening for the sounds of detonation (especially at low rpms and high loads).

The knock sensor (if you have one) will help to make sure you aren't doing any damage. Otherwise, the lean burn Honda Civic VX guys would always be complaining about holes/cracks in their pistons and burned valves.

Once you get really lean, power decreases, combustion temps decrease and chance of misfire increases.


Below are a few graphics from our discussion a few years ago: https://www.gassavers.org/showthread.php?t=8719

https://www.fuelly.com/attachments/fo...a6755b2c38.jpg



With changes in altitude, pilots of air cooled aircraft engines have a lot more need for mixture control than we do so it is of special concern to them:



https://www.huygens.org/sape/pilotage...s/image012.gif

https://www.huygens.org/sape/pilotage...s/image002.gif

I subscribe to this thread:)

I have also noticed that when I go into lean burn mode my water temps actually drop.

Good luck on your project.:thumbup:

I've got a coolant temperature gauge in the '88 Escort that I'm testing on and haven't seen any noticeable fluctuations in coolant temperature.

On my setup I have data log capability and I will notice a 5*F drop during the Summer months in lean burn. But when its cooler Spring and Fall only 2*F.

Filled up again this morning and mileage was down some even with the increase in the setting on the EFIE, but there was a couple times I forgot to turn it on until I had already driven 3-5 miles, the morning temperatures have dropped off into the 30's the last 2 mornings and we had at least 1 rain day on this fill. This time the numbers were 237.9 miles on 6.246 gallons of gas for a MPG of 38.08. I guess I'm just going to have to play with this thing awhile and see what happens. This is still better than it's been getting most of the time for the last few months.