Adjusting EFIE with a AFR guage

[MtnGoatXJ]

My thought process is, well, scarey if you want to know the truth....

So using the AFR (stand alone O2 sensor) to monitor AFR under normal driving conditions. Then switch on the gas and using the EFIE, adjust AFR back to the baseline.

I'm going to try running up a hill (po-boys dyno) and try adjusting there as well.

BTW this is for a 92 Jeep 4.0 HO I-6 A4 3:55 final gears, factory tire size.

-The avatar pic is a joke- for sure

[D.O.G]

My thought process is, well, scarey if you want to know the truth....

So using the AFR (stand alone O2 sensor) to monitor AFR under normal driving conditions. Then switch on the gas and using the EFIE, adjust AFR back to the baseline.

I'm going to try running up a hill (po-boys dyno) and try adjusting there as well.

BTW this is for a 92 Jeep 4.0 HO I-6 A4 3:55 final gears, factory tire size.

-The avatar pic is a joke- for sure

I've wanted to try watching the change in AFR for HHO on/off for some time, but can't justify shelling out $225 (cheapest) for something I'd probably only use once. My cars don't run O2 sensors (too old), so I'd be looking at a wideband sensor stuffed up the tailpipe.

Some questions though, are you adjusting the effie on the stand alone sensor? Or the original sensor? Or am I reading this wrong (again).

Either way, I'd be interested in any data you can share.

[MtnGoatXJ]

I found a very reasonably priced ($80) narrow band AFR by "Koso". I'm guessing they were discontinuing the product. A two wire O2 sensor (my spare off the shelf) was located a few inches down stream from the original sensor. The EFIE is in series with the original sensor of course.

The AFR was monitored for almost a year and the baseline was 14.5-9 indicated on the gauge. With the EFIE off and the generator on, I can now see the AFR climb to the lean side about 15.0. So I adjusted the EFIE to return to the baseline AFR. It seems right, but the mileage dropped from 15-16mpg to 13.

[BioFarmer93]

Let me state right off of the bat that I know nothing about this end of the process (electronics)- I'm a gas carburetor & diesel guy. Having said that, what would adjusting it back toward the richer baseline accomplish for you? I'm sure I'm missing something here, but it seems non-intuitive to me.

[myoldyourgold]

The AFR was monitored for almost a year and the baseline was 14.5-9 indicated on the gauge. With the EFIE off and the generator on, I can now see the AFR climb to the lean side about 15.0. So I adjusted the EFIE to return to the baseline AFR. It seems right, but the mileage dropped from 15-16mpg to 13.

You want to adjust the EFIE so the ECU thinks it is 14.7 but you should still see 15 to 16 or higher (only if the header is not heating up) at the second 02 sensor. If you adjust the EFIE so your second 02 sensor reads 14.7 then you and are not helping anything but making it worse thus the poor mileage. The result is very interesting and make sense to me.

At what rpm are you taking the reading? I would suggest you adjust at what ever your cursing speed/rpm is, unless you are doing mainly stop and go.

Keep us up dated. It would be a lot more accurate if you could use a wide band for the second O2 sensor. Excellent work, keep it up.

[MtnGoatXJ]

Most of my driving is stop & go. Been nursing the throttle for years to get 15MPG on pump gas. Been monitoring the AFR guage for that long as well. So making any setting changes on the EFIE is done at steady state throttle on the flats at around 40-50 mph. We live in the hills north of Yosemite so finding flat ground is rare. Usually going up or down a hill between 1700 to 4800ft elevation. I found that running lean will reduce mileage. So I'm working backwards from too rich.

Today I backed the EFIE adjustment to full off (with HHO On should be rich) then up 1/2 turn as another poster here spoke of. I'll hookup a DVOM to get some actual voltage numbers to report back.

Correct me if I'm wrong, the O2 sensor makes .45mv nominal @ 14.7:1 AFR

Cheers!

[D.O.G]

I found that running lean will reduce mileage. So I'm working backwards from too rich.

There's a graph on the atlanticZ site showing the relationship between Air-Fuel ratio, power and economy.
It shows maximum horsepower at 12.5:1 and maximum economy at 15.5:1.

Adding HHO may allow a leaner ratio than 15.5:1, but it's probably a reasonable point to aim for.