VX lean burn monitor - enhanced how to desired

[93dagsr]

Originally Posted by rlprlp1

I carfully shaved the insulation off the two wires just enough to solder into them. Taped them up when i was done.

which ones??...pics??..

[GasSavers_vxhatch]

Everything you need to wire a voltmeter, including wire color codes is in the main post, http://www.gassavers.org/showthread.php?t=2427

What I would like to implement instead of a voltmeter is a dash light that glows when in lean-burn mode. I noted when a new member from Portugal described his Civic has a Honda provided "ECONO" indicator that lights when in lean burn. Here's the post: http://www.gassavers.org/showthread.php?t=5535
Read the 5th paragraph and check out the 2nd pic.

A simple comparator circuit could be built to switch a dash mounted LED on whenever the monitored voltage is in the lean-burn range. I'll try and post back with a sample circuit next week.

Doug

[GasSavers_TomO]

Originally Posted by vxhatch

I noted when a new member from Portugal described his Civic has a Honda provided "ECONO" indicator that lights when in lean burn. Here's the post: http://www.gassavers.org/showthread.php?t=5535
Read the 5th paragraph and check out the 2nd pic.

That members car is an OBD2 version of Civic and that motor is a D16Y5. Different coding than our OBD1 VX so he has a little more bells and whistles from the factory with respect to indicators.

Originally Posted by vxhatch

What I would like to implement instead of a voltmeter is a dash light that glows when in lean-burn mode.
<snip>
A simple comparator circuit could be built to switch a dash mounted LED on whenever the monitored voltage is in the lean-burn range. I'll try and post back with a sample circuit next week.

Doug

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.

Originally Posted by rgsRSX06

careful with the lean burn, you could get detonation/pining and destroy your engine in short order. You should if you have a Honda check out Hondata for an ecu upgrade that lets you tinker with air-fuel and timing.

Jadziasman is talking about monitoring the signal from the LAF (Linear Air Fuel) sensor currently found on all federal emission 92-95 Civic VX models. There is no modifying of the factory settings for lean burn and therefore no danger of ruining anything.

The P07 ECU that controls the D15Z1 motor is not "chippable" in the known sense of the tuner world. Therefor, Hondata wants nothing to do with the P07 ECU as it uses a 16bit code that differs greatly from the normal 8bit Honda coding.

Originally Posted by jadziasman

So, to those of you who have already wired up their lean burn monitor to D14 and D16, is there any way of doing this without cutting the existing wiring?

I won't be able to take any pictures for a How-To for a while due to it being really cold out. But to let you know, you don't need to cut any wires, just shave off some of the insulation on the mentioned wires (D14 and D16) and solder on a lead to run to your DMM or just use some of those wire taps that don't cut the wire. I prefer the solder method though.

[jadziasman]

Thanks TomO, I figured you'd chime in on this sooner or later.

I was also kind of interested in if you had unfasten the ECU from the passenger side wall to get access to D14 and D16. I will wait for warmer weather as well before adding this "feature".

And, you will be helping out many VX enthusiasts if you decide to put together an installation kit.

[Sigifrith]

TomO I'm down for a kit when it's ready.

[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...

[suspendedhatch]

Originally Posted by 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...

Actually they did. My 1992 VX was originally purchased in Wisconsin. On the instrument cluster to the right of the trunk-open indicator, there is a white outline surrounding an arrow pointing up. It lights up green when you exceed 2500 RPM below 5th gear. According to the owners manual it is telling you to upshift. The VX was designed with a lightweight flywheel and with engine breathing characteristics in order for it to cruise at just under 1000 RPM. Without this shift indicator light, most owners would never cruise that low.

UNFORTUNATLEY FOR ME, the gas gauge went bad and always indicated full, so I had to replace that portion of the cluster with one from an Si. I kept the cluster face though. I can take a picture and post it up if you would like.

If you want to tap into some O2 sensor wires without cutting and splicing, you can use a technique that I came up with for a similar purpose. It will not be so easy to find the parts due to the rarity of the VX however, but what you would do is get a dead O2 sensor, cut off the plug, then find a junkyard VX, cut off the ECU side of the plug. Now wire together all the wires you don't need to tap into and bypass the two wires you need to go to your circuit then back again. Then you simply plug this homemade adapter inline with your O2 sensor.

[monroe74]

"It will not be so easy to find the parts due to the rarity of the VX"

The method you're suggesting can be implemented without finding a VX to cannibalize.

The VX LAF (wideband O2 sensor) uses an 8-pin connector (even though it has only 5 visible wires). That same connector is used in various places on other EG Hondas (and maybe non-EG Hondas also).

See page 23-16 of the Helms manual. C125 and C107 are used on every '92-'95 Civic, and they are the same connector as what's used on the VX O2 sensor. The next page of the manual illustrates where these connectors can be found under the hood. And I think the same connector might be found elsewhere in the car.

But I think it would probably be easier to just use a 3M tap connector, as suggested earlier in this thread by darkelf, here. Then the wire could be tapped near the ECU. This means no need to run a new wire through the firewall. Also seems like a lot less effort with regard to cutting/soldering/taping.