Erratic Idle

[88325edriver]

I have an '88 325e with an erratic idle on hot days (so all summer here in SC). Does anyone know what would cause this? I have searched and found a few things like vacuum leaks, but where would the vacuum leak be to cause this? Thanks in advance.

[Heysüß]

just start spraying around the engine bay or if it's huge you should hear it. Good to see another upstate e30 on here :D

[bimmer630]

The large boot in between your airbox and throttle body is probably ripped

[davem]

Carb cleaner trick doesn't always work

-vacuum hoses (rubber hoses that run into the intake manifold)
-gaskets between intake manifold and head
-oil cap and dipstick seals
-fuel injector o-rings

etc.

[88325edriver]

The intake boot is good as new. Davem, what is the carb cleaner trick?

Thanks for the help on these noob questions, guys. I don't know nearly as much about e30s as I do about 2002s.

[gillette]

Not to thread jack but I searched and saw this thread come up.
I am having a very similar issue... i just got the e30 a couple weeks ago and am trying to bring it back to life. Got it started and its just revving up and down and dropping very low... Any suggestions?

[jw 325ic]

idle control valve
valve cover breather hose
clean air filter
remove the intake boot and really examine for cracks
new oil cap
check fuel hoses
fuel filter
intake manifold gaskets
fuel injectors/o rings
throttle body gasket
throttle position sensor
o2 sensor?
various vacuum hoses

just an example of the things you should be checking/replacing. hunting a bad idle is pretty tough. sometimes you can get it right with the first part but other times you end up spending some money trying to figure it out. good luck.

[xikyle]

idle control valve
valve cover breather hose
clean air filter
remove the intake boot and really examine for cracks
new oil cap
check fuel hoses
fuel filter
intake manifold gaskets
fuel injectors/o rings
throttle body gasket
throttle position sensor
o2 sensor?
various vacuum hoses

just an example of the things you should be checking/replacing. hunting a bad idle is pretty tough. sometimes you can get it right with the first part but other times you end up spending some money trying to figure it out. good luck.

totally agree with this ^^^^

[bimmer630]

I had a bad dme do it

[MTechnikII]

325e E30s have an idle control module , it's under the passenger side of the dashboard, that might be also acting up, usually the idle control valve and the module are changed as a set same time, the module is a almost 2x2x1 green plastic box with a tab for mounting bolt.
get a different module and try it
Henry