fastegg

I'm just about to install my Dynojet air/fuel ratio gauge. I'd like to start 'fiddling' and try to get better fuel economy on the highway....I have read somewhere if I put a variable resistor on one of the sensors (Intake air temp sensor, coolant temp sensor or other) by tricking the ECU into thinking the engine is running hotter tan it is, it will run leaner. If this is true, which sensor would i use to get the result im looking for ?
... Is there any written info about what I'm trying to do ?
... I'm mainly doing it purely for the exercise because I'm bored and I like doing mods like this...

dicer

There is no tricking it, O2 sensors will keep it all what its suppose to be. Your only option is to find the engineer that designed the ecu and has the correct software. Or go with an aftermarket controller.

Yamae

Use your brain to cheat the ECU. Simply add a bias voltage 0.350 - 0.375V to the O2 sensor. This can change the air to fuel ratio.
https://www.clublexus.com/forums/ls-...s-mileage.html
This sometimes causes a problem at a long downhill, I must add.

djamps

My 98 only gets 15-17 at best city on 91 octane. I feel like I'm being cheated compared with everyone getting 20+ on older ones! Only time I've seen 20+ is on long (hour+) freeway excursions.

dicer

Yamae then you are using a simple voltage divider and a direct connection from it to the signal wire from the O2 sensor to hold it at the .35 or so V?

Yamae

No, it's not a voltage divider. It's a low voltage regulator and a series resistor to an O2 sensor. But only these 2 causes the check engine light ON problem when a continuous light load condition continues like when you go down the long hill without pushing the gas pedal. You need to disable the regulator detecting the vacuum level exceeds and last the limit such as -700mmHg or more.

fastegg

.. Yes Ive read all that... What I'd like to do is run the engine leaner, mainly on the highway.. and there are 4 o2 sensors... telling me to add bias voltage to the o2 sensor means nothing, you'd have to tell me exactly how to do that....

Yamae

Search the Net and you will find the exact circuit.

fastegg

With respect Yamae.... I have no idea what you are talking about...

Yamae

Here are two examples.
http://hydrofueldrycell.blogspot.jp/...-enhancer.html
http://forum.allaboutcircuits.com/th...e-2#post-81917

AmericanLo

Basically it tricks the computer into thinking the engine is running richer than it really is.

fastegg

Um... That's all way above me... thanks anyway... I do not however it gets better fuel economy on the highway if I use premium...