M50 lambda sensor

[joeseth]

Currently there is no lambda sensor fitted to my e30 m50b25TU. Just wondering if anyone else has run theirs without a lambda?

I’m sure it would run/be better on fuel with one.

Next question is will it even be accurate if only fitted into 1 pipe on a dual pipe exhaust system??

Trying to eliminate as much as possible as having an erratic idle and it sometimes dies when you touch the accelerator.

Any help appreciated.
Joe

[Brianmoooore]

The purpose of a lambda senor is to protect a catalytic converter from damage, so with a sophisticated ECU in charge, I would expect it to keep the fuel mixture somewhat lean in the event of the loss of the lambda sensor signal, in order to prevent any chance of unburnt fuel reaching the cat.
A lean mixture would give an erratic idle, and cause hesitation when accelerating from idle, so this fits with what you are experiencing.
A lambda senor is fine in just one down pipe. It won't detect a problem in the other bank of cylinders, of course, but when everything is working, it's signal will be correct. I use a lambda sensor in all E30 engines that I have run on the road, for a different purpose, and I've only ever fitted one in one downpipe.

[joeseth]

Thanks Brian, I was thinking it’d run rich but protecting the cat makes sense. Although I had a lambda down on my e36 328 the other day and it ran rich. I will get a lambda and try fit to the manifold (doesn’t look like enough room) or weld to one of the down pipes. Next bit of fun will be tracing why there is no power coming from the lambda relay! Thank you, will report the results!