High idle

[fastandloud]

Morning all I've a 1986 318i m10 converted to 325i m20 from a 1989 donor car problem I have is on first start up the revs shoot up to 3to 4k then straight back down to 1k it doesn't do it after that until I start it again next day I've checked everything I can think of no air leaks or anything new icv fitted new blue temperature switch trottle body cleaned fuel injectors refurbished any ideas what could cause this

[arrisbmw]

sounds temp related. check the blue temp switch at the e.c.u . which also checks the wiring to and from it.

https://www.e30zone.net/e30wiki/index.p ... emp_Sensor