Lambda Sensor Resistor Query

Griffo · 2 Sep 2008 at 13:00

This is a bit of a random query I know, but it does relate to motors, or at least the lovely gas that comes out the back end.

My '08 SV650 is having an Akrapovic exhaust plonked on at Suzuki (which means cutting a pipe meaning O2 sensor is lost), however they've just called to say that the '08 model runs double the voltage through the oxygen sensor compared to the '07 and nobody they've contacted seems able to provide a resistor to attach to the cable to stop the ECU throwing an error.

I've already posted on the owners forum, but thought i'd try here, I dare say people have had similar problems with cars too. Is there a way to work out the resistor needed and do it that way, electronics-shop style? The garage guy thinks fuelling may get messed up if we leave it, which I'm hoping would only be when cold, but unsure. Either way, any suggestions pint-buyingly received!

Dogbreath · 2 Sep 2008 at 14:37

I would have thought the easiest solution would be to get a bung welded into your exhaust to take the sensor?

There is no way to emulate the action of an oxygen sensor with a simple resistor, unless it's just the heater circuit that throws an error?

Griffo · 2 Sep 2008 at 15:05

I think it is (or was) just the heater circuit, as this resistor method worked on the '07 version. I'm trying to get in touch with a guy at a tuner place at the moment to see if they've found a way round it.

Welding does look like the best option, though Suzuki can't do that for me.

Dogbreath · 2 Sep 2008 at 15:15

If it's just the heater that causes a problem, then measure the resistance of the heater in the lambda with a DMM (they are usual around 12 ohms) and get a suitable resistor from Farnell etc. It will need to be a hefty resistor though, there will be quite a bit of power dissipation.

If it's not been fitted yet could you take the pipe to a stainless steel fabricator? They could TIG weld a boss in neatly, and you can buy the bosses for a few quid from e.g. online auctions.

dalin80 · 2 Sep 2008 at 16:56

I would have thought that getting a threaded hole put in would have been a much better solution. The heater circuit packs a substantial current if memory serves so any solution would have to be a good one.

Griffo · 2 Sep 2008 at 17:22

Yeah thanks, it does sound like the best bet, but I'm not sure what sort of place would do that. I don't want some backstreet garage messing it up and the world ending.