my friends 89 525i is having a idle issue where it idles like ****. his mechanic said it was the idle control valve. im pretty familiar with the M20 as I have had a 90 325i.

he ordered one from bavarian auto recycling and they sent the wrong one, the one they sent was for an M50.

either way whenevber i pulled the ICV connector off the idle would get worse and whenever i plugged it back in the idle got better. is this normal or is the car supposed to stall?

i told him to send it back and have them send him the correct one since he already paid for it. but upon further inspection the breather hose has a nice crack in it as do the hoses that connect the ICV. are there any other places to check? my theory is that the ICV is still good and there is a vaccum leak somewhere that has to be discovered. the M20 sure looks small in the E34's engine bay. or im just used to seeing an M60 in mine.