My DIY Wide Band O2 Experience.

635 Views 8 Replies 2 Participants Last post by Kevin Hoare, Feb 19, 2002

Kevin Hoare

Discussion Starter · Feb 17, 2002

We tried the O2 unit on the road today.

We made up a test pipe with the O2 sensor fitted and put it in the tailpipe of my car (Integra) and my friend's car (WRX). The test pipe consisted of a foot long piece of 1.25" copper pipe with the O2 sensor affixed to it.

The LED on the heater board was on constantly when it was in my car and the AF display jumped around anywhere from 14.2 to 14.8.

When we put it in my friend's WRX the display started at around 14.7 and would sometimes briefly jump up to around 18. I would have expected the oposite (IE: the AF going lower when it was in the boost) The LED on the heater board flickered for awhile then went out.

Obviously something isn't quite right. Has anyone else tried testing their unit on the road? What should the #'s look like for a naturally aspirated car? I won't have my Supra on the road until the spring.

Anyone else's experience would be appreciated.

Kevin.

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sidwin

· #2 · Feb 18, 2002

What was your friend's voltage reading? Remember that the pcb will flicker when it doesn't get 13.8v coming from the alternator. When you are driving and let off the gas with the car in gear, you will go lean. Putting it in neutral and u will go rich. Is your display calibrated yet? It is reading 14.7 at idle? My pcb flickered and drove me nuts. I couldn't figure out till I noticed the relationship between voltage and the a/f.

Sid

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Kevin Hoare

Discussion Starter · #3 · Feb 18, 2002

sidwin said:
What was your friend's voltage reading? Remember that the pcb will flicker when it doesn't get 13.8v coming from the alternator. When you are driving and let off the gas with the car in gear, you will go lean. Putting it in neutral and u will go rich. Is your display calibrated yet? It is reading 14.7 at idle? My pcb flickered and drove me nuts. I couldn't figure out till I noticed the relationship between voltage and the a/f.

Sid

We didn't actually check the supply voltage. We only checked it quickly. We'll have to do some more testing soon.

If the LED on the heater board isn't on, does this mean that the IP circuitry isn't enabled? I have a feeling that something may be wrong with this circuitry since the LED was flickering then went off on the WRX.

Yes I have calibrated the display and it seemed like I was getting the behaviour of rich / lean as you described on my integra. It was varying between 14.2 to 14.9. In this case the LED was on all the time.

Kevin.

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Kevin Hoare

Discussion Starter · #4 · Feb 18, 2002

Looks like it may have been a power voltage issue. This thing definitely needs the 13.8 and a decent guage power wiring. I presume the WRX wasn't generating enough power through the cigarette lighter.

Another question. What voltage/AF do you guys see if the sensor is fully heated and the car isn't running? I seem to get around 17:1 however if I probe the the pin with my DVM It seems to creep up to 20:1

Thanks
Kevin.

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sidwin

· #5 · Feb 18, 2002

I have gotten mine to work at 13.3v. After I installed that huge heat sink, i notice the led light stayed on but not super bright.

I have no idea about the last one because how do u get 13.X volts to power the unit without the car running?

With the car turned off and the key turned to on, I get 14.7v and this is due to the pcb not getting enough juice.

Sid

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· #6 · Feb 19, 2002

guys,

off topic, can someone explain to me whats the internal/mechanical difference between the wideband O2 sensor and normal O2 sensor?

also, how does it detects amount of air and fuel mixture from exhaust gas? does it detect base on heat only?

thanx!

Jonas

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Kevin Hoare

Discussion Starter · #7 · Feb 19, 2002

sidwin said:
I have gotten mine to work at 13.3v. After I installed that huge heat sink, i notice the led light stayed on but not super bright.

I have no idea about the last one because how do u get 13.X volts to power the unit without the car running?

With the car turned off and the key turned to on, I get 14.7v and this is due to the pcb not getting enough juice.

Sid

I was playing around with the unit again tonight. I hooked up to my Integra I measured 13.3v on the board. This was good as you stated to dimly light the LED. I am currenly using a cigarette lighter adapter with fairly flimsy wire. Hopefully using a heavier guage wiring will help out.

I never thought about not being able to get the proper voltage with the car turned off. I had mine on my bench hooked up to a power supply at the time. I would have thought the AF ratio should have read >=25 when just sitting in the open air.

Have you verified that the readings from your sensor are accurate?

Kevin.

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sidwin

· #8 · Feb 19, 2002

I have mine hooked up to my seat heater fuse. At idle with your lights off 13.3v is what my car has for output. I use my greddy turbo timer to see this.

I have spoken with steve hayes about his fjo and it looks like mine is working right. i also spoke with pete d who has a motec and looks good. You were able to supply 13.8v when u tested this in your lab? We weren't able. What we did to simulate was we gave the pcb different voltages to see if the output would change.

Sid

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Kevin Hoare

Discussion Starter · #9 · Feb 19, 2002

The only thing I wonder is, is IP circuitry fully enabled when the LED is just glowing dimly? The optoisolator enables the circuitry which outputs the voltage of the O2 sensor. I'd presume so from your experience.

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