Lambda sensor keeps breaking

[H-viken]

A friend of mine runs ITBs on a 2,7L and he’s installed a lambda sensor after the collector on the driver’s side. Challenge is the lambda sensor keeps breaking. Any thoughts on what may cause it? Is this a known issue?

Cheers

Johan

[VFR750]

I have had bad luck with Bosch 4.2 style sensors. They last a few months

If you have any oil blow-by on start up that will kill them quickly. Which is an air cooled engine trait.

I’ve installed a Rothsport check valve and that has greatly reduced the smoke on cold start. I have not replaced the 4.2 since then so I can’t prove that it will increase the life of the sensor.

[H-viken]

Thanks! I’ll pass it along

I believe he has the 4.9 sensor but guess oil is equally bad for it?

[VFR750]

I have the 4.9 on the left and 4.2 on the right.

Both did not survive the fresh rebuild I did in 2018 The break in oil was really the issue.

I’ve had another set go fairly soon after that.

Finally the 4.9 has settled down, but the 4.2 is not working.

But, ultimately oil and rich burning mixtures are pretty hard on O2 sensors

[trond]

also condensed water in the exhaust system, droplets, will kill the sensor as they hit the warned up sensor. Try a delayed switch on of the sensor. I set a 20 second delay and 2000 rpm in the megasquirt to avoid having water droplets hitting the warmed up sensor. No issues after

[H-viken]

Anyone hear about or suspect vibrations being the culprit?

[safe]

Is it installed in a horizontal or above location?

Oil blow by failure assumes that you have connected the crank case to the intake. I have my crankcase ventilated to the air.
For me, a 4.2 has lasted almost 10 years. Its installed a bit further back towards the muffler.

[H-viken]

It’s installed at a slight upwards angle about halfway between muffler and collector

[JoeMag]

Do you mean the sensor end is pointing up, or the wires on the back of the sensor are pointing up?

[H-viken]

Originally Posted by JoeMag

Do you mean the sensor end is pointing up, or the wires on the back of the sensor are pointing up?

Sorry for being being unclear. Wires are pointing upwards at ca a 45 degree angle

[Aircooled4evr]

Originally Posted by H-viken

It’s installed at a slight upwards angle about halfway between muffler and collector

I also did this on a stubborn engine, that kept killing my lambda sensor.
This cured the problem for me.

Originally Posted by trond

also condensed water in the exhaust system, droplets, will kill the sensor as they hit the warned up sensor. Try a delayed switch on of the sensor. I set a 20 second delay and 2000 rpm in the megasquirt to avoid having water droplets hitting the warmed up sensor. No issues after

That is a pretty good idea ... I will definitely try this!