Lumpy idle problem until warm...

[Ditroia]

I have a 1990 316i...when the car is started from cold in the morning it kicks in and then the revs fall to around 500rpm and it cuts out. I can stop it from cutting out by keeping the revs up for a minute or so (it sounds and feels lumpy whilst doing this) and once the engine is warmed up the idle returns to normal levels and feels much smoother...any ideas?!

[spp320i]

Have you checked that the Idle Control Valve is working properly? that would be the first thing to look at in my opinion.

[Ditroia]

I'd have thought that the idle would hunt around if it was the icv? It doesn't do that at all.

[Hellbound]

Same problem with my 325. Only lasts a minute and no amount of pumping the accelerator helps keep the revs up. But after that its absolutely fine and sits at idle really well. Talking in to be looked at this week.

[Ditroia]

Let me know what you find please dude!

[jscazuk]

Exactly the same thing happening to my 325i Touring as well, got it booked in for Tuesday

[bobbin1982]

OMG sounds like the cutout bug......they warned us about this when the millenium started

[Barx325i]

that'd most probably be a giant hole in the breather piping. worth a check before taking it to a 3rd party

[Ditroia]

this problem resolves itself once the engine is warmed up...would it behave like this if it was a hole?

[Nobby_N]

ICV i reckon, my last one had same problem, i got fed up and sold it lol but now im back for more lol

[Barx325i]

i believe so, the ecu will 'choke' on start, so lots of air will lean the mixture too much.

when it's warm, do you get a flutter/amost stall when the engine decays to an idle?

[Ditroia]

not really, once warm it sits around 900-1000rpm and is quite smooth!

[toby]

Suggestions:
Remove and clean out the ICV with brake cleaner
Check the rubber air intake elbow for splits - visually and spray WD40 over it and listen for an engine note change. Also spray some over the pipe which goes from the rocker cover and under the inlet manifold.

If it's still bad it would be worth investigating or just replacing the engine temperature sensor which is blue and bolted into the thermostat.

[spp320i]

Suggestions:
Remove and clean out the ICV with brake cleaner
Check the rubber air intake elbow for splits - visually and spray WD40 over it and listen for an engine note change. Also spray some over the pipe which goes from the rocker cover and under the inlet manifold.

If it's still bad it would be worth investigating or just replacing the engine temperature sensor which is blue and bolted into the thermostat.

What he said!

Even though it seems strange to me that it should run smoothly when it's warm, I'd still check the most obvious things first - air intake and ICV. If you can eliminate these as not the cause of the problem, it's best to do so, otherwise you may spend weeks and £££'s trying to figure it out, when it could be something very simple.