Lumpy idle

[Danny06]

Can anyone help?

My sport has a high lift cam in it, but on idle it chugs and u can smell fuel real bad. it idles at the right speed just very lumpy but as soon as u give it some revs its fine. Iv just recently changed the rubber boot pipe that leads 2the afm & put a manafone gasket on , still no change, also she has a tendency till die out wen she is idlein wen cold or at low revs any 1help??

[jonbuoy]

Lumpy idle's are usually caused by air leak's but try cleaning your Idle Control Valve first mate
It does also sound like it's over fueling...alot! Maybe just from cold but you should check for any fuel leak's from perrished pipe's

[woodysjw]

Ditto Dude take a look at my thread Head change lumpy idle,

[Danny06]

Changed the idle control valve from a mates car made a wee bit of difference i thought but not a lot!! its reali raggin me as its my first e30 and wen people here it day would fink wot a ball of scap but she goes/drives 100% in every other wey....

[Martinaston]

Air filter ?

[bottlecapE30]

if you have no air leaks then i would guess it might be the idle modual it is common that the sodler welds will break inside and the wires no longer make a good contact
hope this helps

[Globulator]

If you really have no fuel leak (check/replace filter to rail pipe) then it sounds like you have a slight valve overlap. Even a slightly tight tappet will cause a rough idle and the smell indicates the same.
So check and adjust your gaps!

[keith52]

Same problem with mine , somedays on tick over the car rocks from side to side , thanks for the above suggestions , its also not as rapid as before the tappets were readjusted ( no power surge at approx 3,000 revs)

[Danny06]

Would any of the above make it slightly harder 2start?? seams till take dat wee bit longer till start and wen it starts the revs r goin up n dow n possible dies out some times at this...

[Danny06]

bump

[jonbuoy]

Valve clearance's mate

Had the same problem, done the valve clearance's today and she run's a whole lot better And start's quicker and easier

[Jhonno]

dude you have a high lift cam.. there's you answer - they get lumpy on idle with a more aggressive cam profile

[jonbuoy]

dude you have a high lift cam.. there's you answer - they get lumpy on idle with a more aggressive cam profile

I thought that till i read the last bit of his question;

also she has a tendency till die out wen she is idlein wen cold or at low revs any 1help??

You do get a rough idle with a high lift cam, depending on profile, but they're not designed to make the engine cut out and it seem's that his engine is over fueling real bad

[Jhonno]

lumpy idle does smell like its overfueling.. hence why big cams arent MOT friendly

missed the cutting out bit tho

[BMW_YARD]

lumpy idle does smell like its overfueling.. hence why big cams arent MOT friendly

missed the cutting out bit tho

If you 'slacken' off the tappets, you will reduce the valve opening period to nearer standard, and bring back some of the engine/cylinder heads efficiency at idle, this will reduce the amount of HC's in the exhaust.

With long duration cams, the exhaust pulse is pulling enburn't fuel across the engine and this will effect emissions if not set up correctly.

Big road/fast road cams shouldn't be a MOT problem, Schrick cams will also provide a TUV certificate for emissions.

This guys issues sound like they are in addition to his cam.

I'd also check/swap the coolant temp sensor for the DME (Blue two pin on the thermostat housing)

It's his first E30, maybe it's not got a cam and it's just running like a pile of $*!#

[BMW_YARD]

Would any of the above make it slightly harder 2start?? seams till take dat wee bit longer till start and wen it starts the revs r goin up n dow n possible dies out some times at this...

Check the idle switch

Basic check is to listen in the area of the throttle body when you make the first movement of the throttle.

Poor starting and dying can be caused by the DME nto recognising th eidle position.

Although the throttle idle position screw shouldn't need to be adjusted.

Muppets usually adjust this to 'mask' other problems they can't fix.

Get it checked

[Danny06]

Iv got the problem sorted just was a matter of ajustin the alen key fingy in the afm but wen we were doin it we noticed that she woz sittin at 2910ppm on the hc emissions and cant seam till get it down till wot is required for mot(1200ppm or less) wot would be causein dat ??