very rough idle

[pong]

525i
m20
1990

the idle is really really rough...

it jumps from 1000 to 1500 rpm...

when i drive it...

u can really feel the idle jumping...

the speed of the car varies as it jumps... but when im
on the accelerator... maintaining 2000... its normal
except that i feel that there is a lack of power.

any help will be highly appreciated.

thanks!

[632 Regal]

as usual I cant help but have a suggestion. Reboot the computer and get a code after error from the stomp test, rebooting first should zero out on the problem at hand, most other errors fix them selves unless its a vacume related deal.

post results

[shogun]

He cannot make a stomp test, as far as I know pong does not live in USA, so no US spec. car.

[pong]

thanks so much...

i think this is a us spec car (imported frm guam)...

but for some reason i couldn't make the stomp test
to work...

talked to friends who know stuff about engines...
all of us think there is a air intake leak somewhere...

the problem is i couldnt find one...

im fearing that the leak might be from the manifold or
something that drastic...

this afternoon... besides the super rough idle
temp started to climb to the red zone.

then driving it tonight... the temp was jsut a bit above the
middle... pretty much normal...

i dunno if the heat (37 deg C this afternoon) and traffic did contribute
a big part of this... but this is the first time it has happened...
( the overheating and the rough idle)
thanks

[E34-520iSE]

It sounds like a vacuum leak to me too. Even a leaking rocker cover gasket will make the rpm buck. Is there any oil clogging the inlet pipes/ICV/AFM? Try removing all of the intake side of the engine, give it all a good clean up and re-assembling it with new gaskets, seals etc.

HTH,

Shaun M

[pong]

ok... did a part by part diagnosis...

it seems that it is the idle regulating valve

T-SHAPE IDLE REGULATING VALVE BOSCH / 3 POL 1 11/1988 13411433626

i tried removing the plug under it... it was supposed to increase idle speed if i do that... but the thing is... nothing changed... removed the hose going to it... tried to control the air using my hand... idle turned out to be ok.

so this is most probably the culprit.

is there a proper way of testing it?

[shogun]

Pong,
my car does not have an ICV, all is controlled by the EML, so I am not sure how to check. But it looks like it is sticking
http://www.realoem.com/bmw/showparts...13&fg=15&hl=13
Did you clean it already?
Here some comments from Shayne
http://www.bimmerboard.com/forums/posts/247714/
http://www.bimmerboard.com/forums/posts/216810/

[pong]

i think i cleaned it thoroughly already...

soaked it in wd40... a lot of dirt came out...

the flap or whatever ur calling it freely moves...

but the thing is... i think its supposed to be spring
operated... but there is no tension...

it just stays in the position that i push it to...

[Morgenster]

i think i cleaned it thoroughly already...

soaked it in wd40... a lot of dirt came out...

the flap or whatever ur calling it freely moves...

but the thing is... i think its supposed to be spring
operated... but there is no tension...

it just stays in the position that i push it to...

When I cleaned mine that happened too. Don't think it's a problem though. Unless someone disagrees and I turn out to be driving around with a shot ICV

[Ferret]

When I cleaned mine that happened too. Don't think it's a problem though. Unless someone disagrees and I turn out to be driving around with a shot ICV

If I remember correctly, the ICV is an adjust device - IE it has a signal to open more or open less instead of being open x% and closing automatically when there's no signal from the ecu...