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-   -   Lambda sensor keeps breaking (http://forums.pelicanparts.com/911-engine-rebuilding-forum/1081256-lambda-sensor-keeps-breaking.html)

H-viken 12-19-2020 11:04 PM

Lambda sensor keeps breaking
 
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 12-20-2020 05:53 AM

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 12-20-2020 10:32 AM

Thanks! I’ll pass it along

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

VFR750 12-20-2020 11:23 AM

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 12-21-2020 11:34 AM

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 12-26-2020 09:55 AM

Anyone hear about or suspect vibrations being the culprit?

safe 12-28-2020 12:25 AM

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 12-28-2020 06:57 AM

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

JoeMag 12-28-2020 11:08 AM

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

H-viken 12-28-2020 08:18 PM

Quote:

Originally Posted by JoeMag (Post 11158105)
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 12-29-2020 01:16 PM

Quote:

Originally Posted by H-viken (Post 11157774)
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.

Quote:

Originally Posted by trond (Post 11150718)
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! :)


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