View Full Version : question about rpm's for e36..? please help?

09-29-2007, 11:24 AM
hey guys,

quick question!!

i've got a 94 e36 325ic, and when i had my 95 e36 318i i had this same problem...!!

when i'm driving and coming to a stop.. if i don't down shift and just put my car in neutral letting the rpm's drop from about 3500 sometimes my rpms will dip below to around 0 and then above 1000 and start to "bob" up and down feels like an unsteady idle..

i'm sure this isn't normal, and i can avoid it by gearing down and breaking, or slowing down in gear and clutching in at around 1500 rpm. but if i just let it drop it sometimes starts to bob..

any idea what this is, anyone encounter this...?

i think i had the same problem on an 88 325i e30, 95 318i e36, and now my 94 325ic e36.... does anyone have an explanation???

Inspire me *wave*

thanks *th-up*

09-29-2007, 11:57 AM
Sounds like a vaccuum leak to me. It's not "supposed" to do that, in any of those cars.


09-29-2007, 11:59 AM
^^^ i figured that,

but, it only happens when i let the rpm's drop..!


09-29-2007, 12:02 PM
Yep. The ECU is compensating, keeping the engine running. If it's a slower RPM drop it can do this transparently, but when it's quick you'll notice it.


09-29-2007, 12:13 PM
aaahhh..!! I see..

so possible vacuum leak?

09-29-2007, 12:16 PM
It's a likely culprit.


09-29-2007, 01:27 PM
Bro, let your car idle with the hood up. Take the oil cap off. Does the idle change?

if not, you have a vaccum leak.

09-29-2007, 06:14 PM
^^^ thanks...!! i'll do that..!

i suppose i do this when the car is cold??

09-29-2007, 09:51 PM
nate, i just found that culprit was my ICV hoses. check yours..

09-29-2007, 09:53 PM
really?? thanks Ian..!

how'd you fix it?

10-01-2007, 01:20 AM
well, I just took em off, placed new ones that's been sitting here for a while...

if you're going to do this anytime soon, let me know if you need help, as im willing to.