Leaning fuel mixture and effect on engine temp

[Flatland2D]

I really like Honda's fuel gauges. The fuel gauge in my last car was all over the place. It would also fall slowly until the last few gallons then drop dramatically. In my Del Sol it takes a few minutes to get a full tank reading after filling up. This is because the low fuel readings are getting kicked out of the average by the new ones, and the average slowly works its way up. Have you have bad experiences with Honda fuel gauges?

[SVOboy]

Originally Posted by Flatland2D

I really like Honda's fuel gauges. The fuel gauge in my last car was all over the place. It would also fall slowly until the last few gallons then drop dramatically. In my Del Sol it takes a few minutes to get a full tank reading after filling up. This is because the low fuel readings are getting kicked out of the average by the new ones, and the average slowly works its way up. Have you have bad experiences with Honda fuel gauges?

Haha, good fuel gauges must be a 92+ thing. If I take a hard turn (90 degree at 35 or 40 mph) it'll go from 3/8s tank to empty. Damn I hate that thing.

[Matt Timion]

I've never had a bad experience with the EF fuel gauges, but i've heard enough bad things from other EF owners to know it's a problem.

Actually, my fiance's 87 CRX has a problem where it takes around 200+ miles to get to the 1/2 mark on the gauge. it then empties in the next 100-150 miles.

[SVOboy]

80 miles: Leaves full
220: Half tank
300: Empty

[dfoxengr]

a good idea for leaning out your fuel for daily driving would be something like a piggyback tuning unit that is universal, and an egt.

basically

apexi S-AFC
autometer EGT gauge
roughly costing about 200$ when purchased used. and universal on any FI car.

then just experiment with what gives you some gas mileage increase, and doesnt run too hot.
also may want to retard timing some with this idea.

[SVOboy]

Originally Posted by dfoxengr

then just experiment with what gives you some gas mileage increase, and doesnt run too hot.
also may want to retard timing some with this idea.

What is the effect of retarding the timing?

[dfoxengr]

to reduce knocking/pinging.

[SVOboy]

Okee, that makes sense.

[GasSavers_chuckster]

Originally Posted by Flatland2D

I've heard that running a leaner fuel mix will make the engine run hotter because there isn't extra fuel to absorb some of the energy. I am considering making a microprocessor based EFIE-like device that would hijack the O2 sensor signal and scale the signal higher or lower so you can fine tune your mix. I'd also like to add a bar graph of fuel mix for aid in tuning. I have it all designed, it's just a matter of buying some extra parts and piecing it together. My only reservation is this possible rise in engine temps. Should I just keep a close eye on the thermostat, or should I wait till I can rig up a water injection system?

If all goes well with my device I will probably post plans. I don't know if it's really worth the time and effort to get into selling fuel saving devices.

I had the exact same idea!! If you can intercept the signal and "Skew" the voltage..you can acheive a higher AFR and still tell the PCM everyting is Kosher.. I guess you need to tell the O2 to give a higher voltage to make the PCM "THINK" it's Richer... then when the PCM pulls fuel to get it to normal you are actually leaning it out.. I'd like to hear more on this..I really do not think water injection is needed..As long as you don't go crazy..
There is a mode in some PCMS called Lean Cruise Mode.. They actually change the target AFR to like 15.X or so... Usually good for a few more MPGs... Illegal in the US because it causes higher NOX in the Air..
LEan Cruise kicks in when the car has a low Throttle position and maintaining a constant cruise speed...

Lean Cruise is used in Austrailia