Cheap DIY EFIE
 

So the other day i found this video on youtube http://www.youtube.com/watch?v=PEHJ9...eature=channel I have been wanting to make an EFIE for a while and i didnt want to spend alot of money so this was perfect for me. The parts cost about $10 at radioshack. I went to hook it up to my Saturn and there was only 1 O2 sensor wire so it was pretty simple :cool:. At first when i started to test drive the car with it on i thought it wasnt doing anything, then i cranked it all the way up and the car started to hesitate and miss so i turned it back down to where it would stop hesitating and i set it at like 450mv. That seemed high to me but i just drove along and my temp gauge started creeping up so i backed it down and ended up setting it to 300mv. The car has lost some power but it still accelerates smoothly. I just filled up and i'm going to leave it set at 300mv until i need gas again (unless something happens and i have to adjust it). I'm getting right around 40mpg consistently so i should be able to tell if it makes any difference. I will let you all know the results in a few days.

Yup, lean burning will get you some mileage, just watch it on heavy acceleration if you want your valves & pistons to live. OEM lean burn engines have set conditions where they will enter lean burn mode, you don't have this.

FYI, the EFIE is a horrible way of controlling lean burn air/fuel ratios. The normal narrow band sensor's resolution is absolutely horrible at measuring anything outside of its normal band.

Not tryin to be a kill joy, just a word of warning.

Most likely, your computer will think the O2 has gone crazy and just compensate and you will end up with the same mpg as you started with.

As long as his computer doesn't catch on he will get better FE.

His NOX emissions are going to skyrocket though.

Daox, is there a preferred way to control air/fuel mixture? Just wondering as that is one of my next mods I want to do. With fuel additives, warm air intake, and other ideas- I would like to get results without the car's computer overcompensating and sabotaging my efforts. I'm also aware of the dangers of knocking, pinging etc....
Is there a dependable device out there for this, beside a ecu tuner type program on a laptop, etc? thanks

Compensating for an efie/lean burn
 

What I am working through at the moment is combining
water-injection with lean burn.

I am led to believe that one third of fuel is used as an
internal combustion chamber coolant.

During combustion, it's the vapour that explodes and
the fuel liquid is just exploded and sent to the cylinder
walls to cool them.

If you go lean, you are just reducing the fuel component
that was destined for 'cooling'. That's why everything
'goes hot'.

Apparently, you can substitute that fuel for water and
it will achieve the same effect.

thanks for the word of warning guys my engine temp has been creeping up more then usual in stop and go traffic and driving around town. The temp is ok anytime i'm going over 40-45mph. I reduced it down to 200mv today because of the temp. Also from what i can hear there is no pinging or knocking not even under load in high gear. The car is terribly gutless though and i'm thinking about changing it back to stock but i want to test it out a little more before i remove it.

EFIE removal..
 

The last thing you want to do is burn your motor out.

Another thing about running a motor lean is that it
is the metal surfaces that get hot and the temperature
doesn't necessarily make it to the heat trashcan (radiator).

So what can happen is that you can burn out your
outlet manifold valves even when the temperature
looks 'normal'.

Apart from that, you can congratulate yourself in
that you successfully were able to use the efie to
lean your motor out.

That part at least did work.:thumbup:

My thoughts exactly...
 

My Camry's AF ratio gravitates to 14.53 constantly. Drive me crazy. Only time it gets above 14.65 is for a few cycles when you let up on pedal to start a nice coast. After a few seconds ECU gets its right quick back to 14.53. I believe it has to do with drive-ability and durability.
Water injection I hope would allow leaner ratio and cooler combustion temps.
I need to search for a good how to build your own water injection as the commercially available systems are too expensive.

Pete

I know that it would take more circuitry and work but if a EGT sensor was installed to monitor the temp and when the temp reaches X amount switch back to the standard O2 readings. This would be accomplished with a low power relay that would have the EGT lead ran to the coil side where the when the voltage reaches the point to activate the internal switch it will bypass the efie.

This assumes that the EGT will increase in voltage with temp if not then the function will have to be reversed. The only other parts that might be needed would be a diode, resistor, and maybe a variable capacitor. Those would be just to help set the switch on/off point and prevent feed back.

I'm at work so I can not work the needed values or parts out that would fit it but the concept is there.