VX lean burn monitor - enhanced how to desired

[dogncatboy]

Originally Posted by TomO

I'm in the process of getting a kit together that will do exactly that for the VX owners. I'm still amassing parts though. I'm thinking that I should be able to get a kit together and out the door this spring if things move smoothly.

I'll take one when ready.

[GasSavers_vxhatch]

Originally Posted by TomO

I'm in the process of getting a kit together that will do exactly that for the VX owners. I'm still amassing parts though. I'm thinking that I should be able to get a kit together and out the door this spring if things move smoothly.

I'm definitely interested.

When you have a schematic drawn up would you be willing to post it? I'm interested in how the comparator LED switching circuit should be wired. I can have a electrical design engineer look it over as well if this helps you.

doug

[GasSavers_BIBI]

I would like to have light that tell me when the Lean Burn is on. I'm wondering why Honda didn't put one from the factory, still its a 1992 model...

[GasSavers_TomO]

Originally Posted by vxhatch

I'm definitely interested.

When you have a schematic drawn up would you be willing to post it? I'm interested in how the comparator LED switching circuit should be wired. I can have a electrical design engineer look it over as well if this helps you.

doug

I'm just going to modify the schematic found HERE at Autospeed.

The only difference for monitoring lean burn in the VX as opposed to a regular O2 sensor is figuring out if the potentiometer needs to be changed and if the comparator IC can handle the higher voltage of the Honda LAF.

Feel free to run it by your electrical engineer and post what he says.

BTW the operational voltage signal of the L1H1 tends to be 1.1V-4.6V IIRC.

[4bfox]

Heck yeah! Put me down for a kit, too...I can figure this stuff out usually, but it makes my head hurt. And I don't mind paying for convenience

[GasSavers_vxhatch]

Originally Posted by TomO

BTW the operational voltage signal of the L1H1 tends to be 1.1V-4.6V IIRC.

Tom, the article in your VX links says the ECU connector pins to monitor are D14 & D16. Monitored voltage will be from -1.4 to +0.8V. Lean burn is indicated by a steady voltage above 0.4 to 0.45v. Assuming the article is correct (I haven't personally monitored the voltage), then the LED will be constantly lit in lean burn and off otherwise. I think this is better than a distracting blinking LED anyway!. I'll try n get you feedback on the "autospeed" circuit later today.

doug

[GasSavers_TomO]

^^^ when you hook up the DMM to D14 and D16 you are watching the LAF signal compared to the Reference signal, not chassis ground. You can also hook up your DMM a different way and read the entire spread of the LAF signal. In which case the voltage will always be positive and anything above the reference voltage (2.7V measured from D16 to ground IIRC) will be lean burn. That is the way that I'm intending on setting up the comparator circuit.

I'm also looking forward to your input on ways to modify/use the circuit in the LAF sensory circuit.

[GasSavers_vxhatch]

Originally Posted by TomO

^^^ when you hook up the DMM to D14 and D16 you are watching the LAF signal compared to the Reference signal, not chassis ground. You can also hook up your DMM a different way and read the entire spread of the LAF signal. In which case the voltage will always be positive and anything above the reference voltage (2.7V measured from D16 to ground IIRC) will be lean burn. That is the way that I'm intending on setting up the comparator circuit.

I'm also looking forward to your input on ways to modify/use the circuit in the LAF sensory circuit.

Thx Tom, I also figured this out on my own by carefully reading-digesting & re-reading the original thread. I drew a schematic, based on the autospeed design and had a design engineer look it over. He said it should work fine, but there is a better way to do it. The 470 ohm resistor will be between +12v and ground in the non lean-burn state and as a result it will consume energy while performing no useful work. When in lean-burn, the output of the comparator is switched off (open-circuit) and the 470 ohm resistor serves as a voltage divider to get the LED input voltage into the proper voltage range (and brightness). Along with some schematic changes, if the comparator and LED are selected such that the comparator output current rating is capable of driving the LED on its own, the circuit may be designed to consume no energy in the LEF off state.

doug

If you like, PM me with a FAX number and I'll send you the schematics I've scratched off

PS: In the VX, the indicator will have only two states LED on and LED off, there will be no flashing mode, which I'd find annoying anyway.

[Danronian]

Nice. I'll have to look into this post more when I get back from work.

[Loserkidwac]

any updates?