Monitoring lean burn
 

Alright, so I got an HX ('96, so OBDII) and I want to get instrumentation, but not sure which way to go. So first, is the following correct?

If I get a scangauge II it will screw up the readings whenever I go into lean burn, but I can program it to tell me when it enters lean burn.

Ultragauge will also be thrown off by lean burn and can't show it via custom gauge but can at least tell by watching when the rear 02 sensor goes to zero volts. Also cheaper.

MPGuino will give accurate readings but is harder to install and can't clear codes. Cheapest.
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I am not opposed to a little digging/learning; haven't done any soldering but have tools/help at my disposal. Need ability to clear codes unless I do an exhaust swap.

Given that, what option sounds best? I'm thinking either [Ultragauge + possibly a home rigged lean burn indicator] or [MPGuino + definite home rigged lean burn indicator and either exhaust swap or OBDII scanner*]


*thought these could be had cheaper, but essentially cost as much as an ultragauge so at that point I might as well get an ultraguage too, which would be kind of silly

Creeping up near 100 views and no replies. Hmm.

Well I've done more reading since this and I'm still not completely satisfied with any options I can come up with. It looks like one HX owner on here uses both a scangauge and an MPGuino. I'd really rather not do that unless it's necessary though.

Well, just got my first check engine light and since I'm not replacing the exhaust in the next 2 days Ultragauge just got promoted to the front of the list.

Maybe mpguino later. Would really like to have accurate lean burn numbers as well.

MPGuino is the better choice
 

If you can get your hands on a SuperMID, they show the injector pulsewidth and it is easy to see the pulsewidth shift as it goes into and out of lean burn. Some people have hooked up a voltmeter to the oxygen sensor and watched for the voltage change as it enters and leaves lean burn. Once you know the voltage for lean and non-lean burn it is easy enough to design an LED output that would come on when the voltage was in the lean burn range. For more info go to gassavers.org and search the forum for "lean burn monitor".

Yes, I know OBDII gauges are pretty much worthless for monitoring fuel economy for my car. However, I need a handy way to clear the check engine light, and according to this guy I will at least be able to detect lean burn:

I would like to replace my exhaust with a stock one at which point I wouldn't need the OBDII functions anymore and would be able to go MPGuino. If/when that happens I will probably try to rig up a lean burn indicator as well so I can still track that easily.

Any other tips or suggestions welcome of course. :)

I'm experimenting tonight to see if I can get a voltmeter to work as a lean burn monitor.

I have an HX, and after driving around with a UltraGauge, and MPGuino for a few months now, I think having both is very important as the Ultra can tell you what the engine is doing (lean burn, temperatures, codes, etc); and the MPGuino can tell you perfectly accurate fuel consumption.

If i could only have one, i'd honestly say that i'd go wit the MPGuino. it tell you fuel consumption, AND speed. knowing your "exact" speed, or rather, if you are accelerating slightly, or decelerating slight - is KEY to maintaining a good MPG throttle foot. the MPGuino tells you your MPH to the XXX.XX.

You may go for somethink like this:
(c)koda Felicia - praktyczne porady u¿ytkownika

This is in Polsh so if you have any trouble with google translate it just let me know.

Here is a schematics for this unit (fairy simple)
http://autofelicia.republika.pl/grafika/airfuel.gif

The operation of this is simple 3 LEDs are signaling Lean, Normal and Rich mode. So I think it suits the need to know when engine is working in lean burn mode best.