How often do you replaced your oxygen sensors?

[Genie47]

BTW, you can get a Bosch LSU4.2 from Amazon for USD51. It's the stock VW WBO2 that is commonly selling around.

[Imuya]

Yeah VW cars are running on stock WB same like the Honda K-series. But my old B-series is using NB o2 sensor.

 

So we need a wideband controller to give us the readout, if not the stock ECU cannot use the wideband input and will throw a CEL light. I learnt this first hand cos i wired the whole setup wrong initially.

 

Anyway, replacement WB O2 sensors are about the same price you mentioned. Mine is using the Bosch sensor also.

 

BTW, what's stoich ratio for CNG?

And does CNG and petrol operation ever mix? Cos if mix, how to read AFR?

[Genie47]

Ah! That's where the pros start to use lambda instead of AFR.

 

Stoic Petrol 14.7:1= 1.0 lambda

Stoic CNG 16.0:1= 1.0 lambda

Stoic methanol 6.4:1=1.0 lambda

 

See the pattern?

 

Lambda is actually the AFR reading/stoichiometric AFR. Taking petrol as an example. If the AFR reads 11.4 then lambda is 11.4/14.7=0.77

 

CNG is pretty simple and straight forward. When idling, lambda should be 1.0 and for power, cruising, WOT, 0.83 to 0.85. Most will go for 0.83

 

Our installers don't tune it this way for us. They make the CNG ECU copy the injection cycles and duration and modify the timing. That's all the CNG ECU does.

 

As a rule of thumb, the pros tune with lambda and not AFR since lambda is universal.

Edited May 13, 2008 by Genie47

[Imuya]

Thanks for the heads-up on using lambda. it really simplify things.

 

Is 0.85lambda for max power universal for all fuel types?

[Genie47]

More or less. But there are other things to consider like getting too hot when you get closer to 1.0 when applying power.

[Vtim]

Can WBO2 be used on stock ECUs?

 

Anyway, I found a Walker EGO part number 250-24200 in Amazon. Dirt cheap at USD46.77. Universal precat front and rear.

I don't think so, it's better to check your stock O2 sensor type, there are a few types, 1,2,3 or 4 wired type and my 4 wired type have different colour coded wire when I ask the seller in eBay whether it can be used on my Trajet

[Genie47]

Confirm can. It is 4-wire.

[Vtim]

buy it and send to VPost, cheaper

[Genie47]

I'm looking at the DM5 from PLX. Looks good and the price is good too. The manual says that if I connect the ground wire, I will get lambda readouts instead of AFR. Cheaper than the DM100 combo.

[Imuya]

Woots! Yeap, appararently so. Connect ground for Lambda and unconnected for AFR. With the current exchange rate, should be slightly more than 400SGD shipped.

 

The DM100 is for when you want a single gauge for all your readings (oil press, temp, AFR).

 

You gonna drill a hole in your exhaust pipe or will it be replacing the stock narrowband?

[Genie47]

I got two narrowband sensors for this car.

[Pdesign1]

Found the answer to my question.

Edited May 23, 2008 by Pdesign1

[Weichien]

may i know what's the symptoms of a faulty oxygen sensor.

got very bad fc all the while but it got worst and worst each time. millage about 100k.

[Vtim]

if there is no CEL then it may not be the oxygen sensor, have you check other parts, plugs, air filter, fuel filter, plug cable, ignition coil, leaking exhaust/header etc....

Edited June 2, 2008 by Vtim

[Vtim]

there is a guy in US that replace the NB with WB and it causes the engine to run lean, slight increase in power

[Genie47]

Interesting. Good thing the ones I buy are cheap. Will see if I can get an LPX.

[Vtim]

Will see if I can get an LPX.

---

 

what's that ??

[Genie47]

Sorry PLX. www.plxdevices.com