whats this little device on my e39 ??

[james318i]

hey all , aside from my e30 ive got a 520i touring e39 that i picked up through the trade a while back but ive kinda hung on to it as its a good thing - i wanna keep em all haha

anyways it started running rough at idle , and revving it in neutral then takin my foot off the throttle the revs would hang up 'ala' air leak , i sprayed some carb cleaner on the inlet side and found my suspected cause , under the inlet manifold theres a fairly flat but round box with 1 hose holding it to the manifold , when spraying this it would cause the revs to rise ,

any ideas what this is ? and will i be ok just sealing it up or replace ? i know ive not enclosed a pic etc but its under the manifold pretty much between cyl 3-4 , its a m52 engine i think ?? 1997 car

james

[maxfield]

Hmmm breather?

[james318i]

possibly , id imagined it was something 2 do with vaccum as it seems to be causing my rough idle and air leak . hmmmmm bloody cars lol

[E30Mark]

The bit your on about, is it item 19 in the link below?

http://www.realoem.com/bmw/showparts.do ... g=11&fg=40

[james318i]

cheers for posting that link , had a look through it but cant find the part

had a better look at it today and this thing seems to be vaccum related and it has a slot at the bottom to draw air in and a pipe coming from it , if i cover the hole up it seems to run smoother BUT it makes the brake pedal spongy so it must be something to do with the servo or something

anyway the pipe coming off of this valve thingy was blocked solid with oil/crap build up (145,000 mile car) and had gone soft so i assumed it was closing up under load , replaced the pipe , had a blow through the valve as i couldnt get it apart and re-fitted it , must have still been doing something though as even with the blocked pipe it still made a difference when i blocked the hole up on the valve, afterwards it ran smoother but still rounded rough and uneven from the exhaust , definately a bit better though it seemed , any ideas what that valve is ?

then i noticed if i took the oil filler cap off it evened it out , like the engines not breaking , fit the cap even for a few seconds then remove it and it makes a pshhh sound like its building up pressure so im assuming a engine breather somewhere is blocked ,

when the car went on my dads snap on scanner it came up with codes 202 + 203 which are to do with the sensor on each exhaust manifold , though i reckon the inlet problem is giving them the wrong reading

anyway , drove it home and its not good , doesnt want to rev as easily as it did and its got jerky throttle response at low speed , was always rough at idle with this problem but ok once on the move , now its lost power , can also hear that valve i mentioned drawing in air if i have the window down , maybe its f*cked or maybe its just drawing more as it can actually work properly

any ideas guys ?

[james318i]

well fixed that issue , idles perfectly now , seems the little 'device' was to control the vaccum etc and the diaphram inside was split and dead

anyway , next issue , floor it and it hesitates a bit, seems a bit reluctant to rev out and generally feels down on power compared to about 3 weeks ago , what looks like the airflow meter ? (inbetween airbox and throttle body) has a butterfly in it and is opened/closed by a cable that goes down to a solonoid , noticed if i rev the car this doesnt move , does it only move under load when driving or is it likley the solonoid is fooked ?

james

[Ant]

Sorted

that device is the zyclon valve and its common for the dia to fail and draw unmetered air, collapsing the breather as it goes.

the oil cap trick is the 1st indicator there's an issue

Sorry didn't spot this one earlier dude

the second throttle butterfly assy is for the ASC or DSC , the flap is sprung fully open and is closed on demand by the ECU via the actuator when some slippage(wheelspin) is detected

the device itself is fairly basic, the second TPS on these can fail though causing issues with part throttle running, remove clean and test the TPS on the unit, dump the fult codes and re-evaluate, FYI the valve should go open/shut/open when the ign is 1st powered up( engine not running )

HTH

[james318i]

nice 1 , that would explain whyy it puts the asc light on when i unplug that meter - its all new to me , im a bike mechanic haha

still lacks power , brought up codes 203 and 202 on the snap on scanner which are sensors on the exhaust manifold , if they failed would it cause a power loss and jerky acceleration ?

cheers for your help fella , much appreciated

james

[Ant]

Failed 02 sensors would make it lack so Go, as the ECU will revert to a restriced performance map and not log the fuzzy logic( adaptation values )

the could be duff as a result of oil contaimination from the breather issue, but I'd check the units in live data before binning them.

failed TPS on the ASC unit will also cause the same running issues, its chicken and egg time ...

What mill dude ? M52B20 or B22 tu double Vanos ? I'm guessing the latter from the twin 02 inputs

[james318i]

lost me at the end there fella

[Ant]

gimme last 7 of the chassis no dude

[curryp]

i also have this problem on my m52b28 (2000) but my car cuts out completely when clutch is engaged at junctions for example.it does everything that yours is doing ie taking cap off and the drawing air sound disapears.also now the engine light has come on

is mine in a worse way?

any ideas would be appreciated