Relay question

[mcspike]

Hello

Have an M42 waiting to be dropped in, it's missing a relay on the wiring loom



I have an M40b16 and a M20b25 to scavenge from, are there any that would work on there or am I going to need to buy one?

Thanks

[mark_i]

third relay is only needed if you are running with a lambda/oxygen sensor.

btw the middle relay should be orange coloured...

[mcspike]

I'm still unsure here. Do I or Don't I need a relay in this socket for the car to be running as it should. I.e. is the relay for an exhaust lambda which is irrelevant on this engine?

I am unfamiliar with a running M42, just the lump cluttering up my shed waiting for a home.

If I do need a relay for it it would be this, 61368373700
http://www.realoem.com/bmw/showparts.do ... g=12&fg=35

[Brianmoooore]

This relay socket is present on all post mid'87 E30s, whether they have an M20, a M40 or a M42 engine. The relay powers the heater of a four wire lambda sensor, so is only needed if such a sensor is fitted.
A sensor will only be mandatory (or rather the cat. that it protects will be) if the engine and car production dates are post 08/'91 for a saloon, and only for M20 and M40 engines for a cab. and touring, again if both made after 08/'91.

[mcspike]

Cheers, Brian.