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Stock Oxygen Sensor VS Wideband *Updated with results!*

 
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flosho  



Joined: 01 Jul 2004
Posts: 3153
Location: Eau Claire, Wisconsin

PostPosted: Thu May 03, 2007 9:59 am    Post subject: Stock Oxygen Sensor VS Wideband *Updated with results!* Reply with quote

So I'm thinking that I can place the LC-1 wideband in place of the stock oxygen sensor and use one of the analog outputs to wire into the stock o2 wiring. The analog ouput wire will output just like a narrow band.

Analog output one is 1.1V = 14 AFR and .1V = 15 AFR. This is a
simulated narrowband signal. Analog output two is setup as 0V = 7.35 AFR and 5V = 22.39
AFR.

Thats the output I can use, I'm wondering which one will work with the stock lambda system? What does the stock o2 sensor output for volts?
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Last edited by flosho on Sat May 05, 2007 12:27 pm; edited 1 time in total
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endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Thu May 03, 2007 2:08 pm    Post subject: Reply with quote

I don't think either is "correct" but if I had to choose you need to use the first one. It will basically switch at .5v at stoich. This is all you really need with a stock NB O2 system. It may work a little on the fast side because they so narrowly define an NA O2 working range.

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
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flosho  



Joined: 01 Jul 2004
Posts: 3153
Location: Eau Claire, Wisconsin

PostPosted: Sat May 05, 2007 11:14 am    Post subject: Reply with quote

Ok, wheres the best place to splice into a 12 volt supply, thats NOT the radio accessory wire.

The reason for this is because I hooked up my wideband today and had everything wired, although when I turn the accessories on(which is when I stick the key in the ignition, is this right?) the a/f gauge and volt gauge are supposed to do a full sweep and then back, well mine do about a 3/4 sweep and then "twitch" for ~5-10 seconds and then go back to normal.

I had the 12v line from the wideband spliced into the radio accessory wire, which is the same supply for the gauges. When I disconnect the wideband wire, the gauges work fine, so obviously there is a issue between these two systems(gauges/wideband).
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flosho  



Joined: 01 Jul 2004
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Location: Eau Claire, Wisconsin

PostPosted: Sat May 05, 2007 12:21 pm    Post subject: Reply with quote

Woo, well finally got everything hooked up and able to connect to the computer, and was able to log some air fuels with my LC-1. Seems like Im in the 10.6-10.9 a/f at WOT, i think thats richer than most would want it but its interesting that my narrow band said it was extremely lean.
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Min  



Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada

PostPosted: Sat May 05, 2007 2:02 pm    Post subject: Reply with quote

flosho wrote:
Woo, well finally got everything hooked up and able to connect to the computer, and was able to log some air fuels with my LC-1. Seems like Im in the 10.6-10.9 a/f at WOT, i think thats richer than most would want it but its interesting that my narrow band said it was extremely lean.


What are you reading at idle? ... you calibrated the sensor as per the instructions? ... were did you ground it?

Min
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flosho  



Joined: 01 Jul 2004
Posts: 3153
Location: Eau Claire, Wisconsin

PostPosted: Sat May 05, 2007 2:36 pm    Post subject: Reply with quote

Min wrote:
flosho wrote:
Woo, well finally got everything hooked up and able to connect to the computer, and was able to log some air fuels with my LC-1. Seems like Im in the 10.6-10.9 a/f at WOT, i think thats richer than most would want it but its interesting that my narrow band said it was extremely lean.


What are you reading at idle? ... you calibrated the sensor as per the instructions? ... were did you ground it?

Min



idle: right around 14.1-15.7ish..

calibrated the sensor per instructions.

grounds are all under the dash behind glove box...
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Min  



Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada

PostPosted: Sat May 05, 2007 2:55 pm    Post subject: Reply with quote

flosho wrote:
idle: right around 14.1-15.7ish..


Ok, thats about right.

flosho wrote:
calibrated the sensor per instructions.


Excellent

flosho wrote:
grounds are all under the dash behind glove box...


My recommendation would be to ground it to the engine block or directly to the battery, if your doing a megasquirt installation eventually, be certain to only ground the megasquirt to the block or the battery, and be certain to have the wideband grounded in the same spot. Otherwise you will have to deal with variance between what megasquirt will read and what the wideband reads.

So, what do you think of it so far? 10:1 at wot sounds extremely rich to me, I wonder if there is a way to pull it back to something a bit more sensible, you'll definately be losing power at anything over 11.5:1 ish on a turbo car. 10:1 is almost in the 'rich misfire' range imo

If you start rich misfiring under load, it will show up as lean on your oxygen sensor (becuase of the unburnt oxygen exiting the cylinder that misfired)

Min
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endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Sat May 05, 2007 3:00 pm    Post subject: Reply with quote

Because these gauges are so light amperage users I think I would at least run a temp wire off the negative battery terminal to the same grounding location to see if anything changes. I have read on other forums about grounding problems with the LC-1 plus having the 924's notorious ground problems seems like a recipe for "bad car-ma".

Edit: Ahh, Min beat me to it!!

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....
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flosho  



Joined: 01 Jul 2004
Posts: 3153
Location: Eau Claire, Wisconsin

PostPosted: Sat May 05, 2007 3:20 pm    Post subject: Reply with quote

Thanks for the suggestions guys. Tomorrow after work, or Sunday at the latest, I will recalibrate it.

I will try go get some pics of most of the setup. Behind the glove box, there is some nice shiney metal that I sanded down with my dremel and screwed all 4 grounds in.

The battery is in the back hatch(spare tire well). So I may run a wire from the negative terminal to the system ground on the LC-1 and see if there's a difference.

The rich mis-fire under load showing up as lean on NB makes good sense and seems like a reasonable solution. SO I guess the question is, how do I lean the system out a bit?

BTW, I do have a file of the first real-time log I made, its hard to decipher, because it has idle, and normal driving as well as a couple 2nd gear WOT blurps.

Also, still need a good 12 volt supply for either the gauges or the lc-1. I suppose I could use the battery, but its probably more work to run the wires from the hatch than from the stock location.
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Last edited by flosho on Sat May 05, 2007 3:38 pm; edited 1 time in total
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endwrench  



Joined: 07 Dec 2002
Posts: 1629
Location: Victor, Montana

PostPosted: Sat May 05, 2007 3:33 pm    Post subject: Reply with quote

Being with MS for so long I can't really remember how the CIS system works but I think you will need to figure out a way to increase control pressure then richen the idle back up with the CO adjusting key thingy .

It's so much easier to do with a keyboard

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....
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flosho  



Joined: 01 Jul 2004
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Location: Eau Claire, Wisconsin

PostPosted: Sat May 05, 2007 3:41 pm    Post subject: Reply with quote

Oh, well hopefully within two weeks I will be able to use a keyboard as well.
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Tigger937  



Joined: 11 Apr 2004
Posts: 906

PostPosted: Mon May 07, 2007 5:07 am    Post subject: Reply with quote

Min wrote:
If you start rich misfiring under load, it will show up as lean on your oxygen sensor (becuase of the unburnt oxygen exiting the cylinder that misfired)

Min


Interesting in that it's the opposite of what you'd think it would be. I learned something.

Flosho, where did you get your LC-1 and what did it set you back?
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flosho  



Joined: 01 Jul 2004
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PostPosted: Mon May 07, 2007 5:15 am    Post subject: Reply with quote

I bought mine from ebay, about $190.
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flosho  



Joined: 01 Jul 2004
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Location: Eau Claire, Wisconsin

PostPosted: Mon May 07, 2007 7:19 am    Post subject: Reply with quote

So any suggestions on the 12v switched ignition wire to tap into?
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Min  



Joined: 04 Nov 2002
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Location: Vernon, British Columbia, Canada

PostPosted: Mon May 07, 2007 8:30 am    Post subject: Reply with quote

flosho wrote:
So any suggestions on the 12v switched ignition wire to tap into?


personally I ran the one that runs my ignition module to a relay that had a feed directly from the battery. Since I put the ignition module on the other side of the car. Personally I'd just use whatever, like the radio accessory wire, but run it to a relay instead of the device, and wire up the relay to the device. That way your not going to draw too much power(relay is like 300ma's maybe?) from the switched power source, keeping in mind ignition switchs burn up in these cars somewhat easily.

Min
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