Air-Fuel Ratio

4289 Views 3 Replies 3 Participants Last post by oarngemig, Jul 1, 2009

suprajones

Discussion Starter · Jun 29, 2009 (Edited)

Does any body have an idea of what the factory setting is for the air-fuel ratio on our car?
My local Lexus dealership has no idea,,,,,, Lexus corporate said they would call me back in 2 days but also seemed befuddled.

Reason-
Had car dynoed today,,,,showed a 17.18 ratio,,,,,tech said that was way high and other dyno read-outs I have seen on this forum are around 13-14.
I Have all these toys to install (K&N intake & JOE-Z exhaust) and am worried that if I put them on now, then have a warranty claim later and the A/F ratio was off all along I will have some issues
Thanx all!

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Fig

· #2 · Jun 30, 2009

That sounds like a faulty AFR sensor on the dyno. Its more like 11.7-12.7. Toyota generally runs rich to add more quench and increase reliability. Some "tuners" may try to get closer to stoich, but you have to think about tolerances over temp, pressure and crappy fuel. I will get another opinion or get some OBDII readings.

Fig

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suprajones

Discussion Starter · #3 · Jun 30, 2009

Thanks for your interest/help Figs!
The dyno tech and I both wondered if the sniffer was inaccurate-
2 factors have led me to research this-
1- WHP reading's were 329/330/326 (3 runs are in order)with minimal cooldown in between (that is about the lowest numbers I have seen on any of the dyno numbers posted) Temp= 90 degrees, 20% humidity on Dynojet, 93 octane(no E85 blend)
2- The tech actually pressing the pedal to the floor said the car felt "held back" or "sluggish" durring WOT; and this was before I even questioned the AFR.

I'm anal about my car(s), So I wanna make sure she is runnig like our friends at Toyota and Yamaha mean for her too.

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oarngemig

· #4 · Jul 1, 2009

suprajones said:
Thanks for your interest/help Figs!
The dyno tech and I both wondered if the sniffer was inaccurate-
2 factors have led me to research this-
1- WHP reading's were 329/330/326 (3 runs are in order)with minimal cooldown in between (that is about the lowest numbers I have seen on any of the dyno numbers posted) Temp= 90 degrees, 20% humidity on Dynojet, 93 octane(no E85 blend)
2- The tech actually pressing the pedal to the floor said the car felt "held back" or "sluggish" durring WOT; and this was before I even questioned the AFR.

I'm anal about my car(s), So I wanna make sure she is runnig like our friends at Toyota and Yamaha mean for her too.

I better check mine, I also got 336.

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