Basic O2 Sensor question?

[Bobbyspit]

Hello.
Can the O2 Sensor be wired direct to the megasquirt ?

The wiring diagram says yes, but there are different opinions.

I was looking at a 4 wire HEATED NARROWBAND Lambda Sensor.

Or a INNOVATE LC-1 WIDEBAND SENSOR lambda ? This comes with wideband controller built in to a sealed cable. It features the same award-winning patented digital measurement principal found in the LM-1 & LM-2, and includes digital input, output, and 2 user programmable analog outputs.

Any suggestions. Application 2.0ltr Zetec

THanks

ROb

[trakkies]

You can wire a narrow band direct to MS - but it's of limited use. A wideband is a far better answer, but as you've seen they need with their own ECU which then sends an output to MS.

[Bobbyspit]

Thanks for the reply.

Once I have the engine set up on a rolling road, the narrow band sensor would surfice? Or is the wideband a better option?

Also I see some sensors come with a heater element, if this type is used is the heated element on permantly?

Thanks again

Rob

[trakkies]

A wideband one can be used to autotune even after you've got things right. To keep things within your fuelling map even if other things change. My MS spends so little time at stoichiometric that a narrow band would be of little use. But my car doesn't have a cat.

I have a Tech Edge wideband unit - which is available as a DIY construction kit. I find building such things helps my understanding of them. The heater on that only runs for a few seconds at a start up. The exhaust gasses then keep it up to temperature. I'm pretty certain it inhibits its output when not up to the correct temperature.

[Heribert]

Hi,

As to the "lambda heaters", of the NB type.
The heater is connected to 12 V as soon as the car is running, many wire it in // with the fuel pump which makes sense.

The heater itself is a PTC resistor ( Positive temp coefficient resistor) When at say 20 C it draws around 3 Amps and heats up quite fast. The current draw is then much reduced an when at 250 C it is down to around 50 mA. When the engine is started the exhaust will heat it up further and current draw will be even less.

The high temp is needed for the sensor to operate as an oxy at stoich "switch". At 250 C the reponse is rather sluggish, 100 ms to react is not uncommon. At 500 C it is real fast and reacts in well under 10 ms. Sensors seem to be able to stand 600 C gases, at least that is what I have measured on a very hotly tuned Windsor 351 special


As to WB sensors , I am not even marginally competent or experienced. wiser heads please pitch in!

Heribert

[Bobbyspit]

Thanks for the replies. Much clearer now.

I have decided to go for the TechEdge, it looks a much easier install

thanks again

ROb