I just bought a 2000 HX (188K miles) and would like help determining when and under what conditions it goes into the Lean Burn mode. I have a Scan Guage but also laptop software that will output all the OBD2 data - just learning how to read it. I replaced the upstream O2 as the previous owner didn't do much but change oil and filter for the past 6 years. Also did timing belt, water pump, crank seal, adjust valves, plugs, wires, and rotor. Elsewhere on this site I found a link to the 5 wire O2 sensor and read about it. My passion is to extract as much mileage from this engine that I can. I sold my 86 CRX HF high altitude several months ago and want to get back up into the high 40s or 50s on fuel consumption. Thanks for your replies - Rob

 

I was hoping someone would see this message and offer an answer to it. I now have 202K on the clock.

 

 

Thank you for getting back to me. So is there any way I can determine if and when this AFR is changed into lean burn by reading any of the input to the ECU I could get on a Scan Gauge? Does it jump from 14.6 to 20:1 ratio or is it a sliding scale all the way up ?

 

Lean burn can be monitored with an OBD2 scan tool by watching when the ECU switches to closed loop.

This thread describes how to monitor lean burn via AFR.

http://ecomodder.com/forum/showthrea...deo-28496.html

 

Thanks Ron. Will check this out when I have better computer access.

 

The ECU outputs to an "Econo light" on the dash when in lean burn mode. Use that wire to trigger your own light. Perhaps an interior strobe and black light. Or just be boring and hook up an unused light on the cluster like I did.

 

The HX cluster has a Shift-Up light, not an Econo light.

 

I have a 98 HX 5MT, The spot for the "shift-up" light is there, but blocked off? Was this an option? Do all I need to do is add a bulb?

 

In response to Ron on Post #8; my CRX HF had a shift up light but not my 2000 HX.

 

At least some of the 92-95 VX and 96-00 HX Civics came with the shift-up light.

VX:



HX: