Main Relay Failure

[DesktopDave]

Ordered a new main relay and should arrive in the next day or so. I cannot find the picture where this relay is located? I thought I saved it. I have an E34...any help?

If your 540i is anything like my '89 525i, the main relay should be a white plastic unit plugged into a rack inside the electronics box in the engine bay (just in front of the passenger firewall). BTW, you're in the wrong forum, head over to the E34 forum here.

[pgh880]

The O2 sensor doesn't kick in until it warms up, try unplugging it and see if that help? Have you checked the CTS?

Those symptoms that you mentioned happened to me when I first brought the car . It took me a year for the mechanic to diagnose it . It was indeed the coolant temp sensor .