Poor running, cutting out :(

[Morat]

Folks,
My 325 has recently started being a bitch
Levels are fine, fan just had a new visco clutch after a close call with overheating. It ran sweet as a nut for a couple of months during the heat and now its doing the following:

1. Starting first time on 4-5 cylinders with lots of smoke. If you leave it for a few seconds it clears up and idles properly.

It did that for a while and now...

2. After about 15 minutes in traffic or running steady it will start choking up. Starts smoking, doesn't like full throttle (judders on full chat) and eventually it will just cut out. If you drop the clutch and rag it up to 5.5k revs 2-3 times it will settle down again for a while. If I'm trashing the car round country roads its quite happy.

I've got a new blue temp sender to stick on this week but I'm wondering if there is anything else you guys could suggest that might be causing all these probs.

Cheers!
Morat

[cliffybabe]

Have u check the rubber boot (goes between the air flow meter and TB) for cracks or air leaks???

[Morat]

yes mate, its a new one. Bought it about 2 months ago now.

[cliffybabe]

Blue temp sensor might help, IM guessing u have already clean the ICV

Have u replace the air filter of anything???

[E30BeemerLad]

is the smoke you are getting oily/blue smoke and smelling of the same or is it more of a sooty black?

If it's sooty black and your tailpipes are accordingly so, then that suggests horrendous overfuelling, most prob rectified when you replace the temp sensor. Well, it's where I would start anyway.

[Steviec]

Dumb question time

Where is the ICV and what does it look like?

(Sorry for being thick, im still learning my way around the engine bay).

[E30BeemerLad]

Dumb question time

Where is the ICV and what does it look like?

(Sorry for being thick, im still learning my way around the engine bay).

ICV = Idle Control Valve

In the pic below, look at the throttle linkage and then just to the right of that, there is a silver part sticking out with a hose coming from it. Well the silver part is the ICV. Sits just on the side of the inlet bellow before the throttle body

[E30BeemerLad]

[Morat]

Well, its not sooty black...more blue - which doesn't sound good. On the move it can be white - but its not using any coolant. It does use about half a litre of oil every 750 miles or so.

I've just been out and checked out the exhaust, there's definitely some oil burning, I'm praying that its not valve stem seals - or if it is, its not bad enough once I've fixed the rest!

If you rev the engine with your head in the bonnet (with the throttle cable) there's definitely a sucking noise and a hesitation before it picks up off idle so I think there could be some more leaks somewhere.....

I'll check it again with the engine properly warm, thats when it starts playing up.

Thanks for your help guys, if you have anymore ideas....

[maxfield]

Blue smoke normally means its burning oil and pistons rings are gone.

[E30BeemerLad]

my only other experience of poor idle was down to the inlet gasket going. Symptoms were lumpy uneven idle and also a bit of kangaroo behaviour when crawling along in say 3rd gear on light throttle trying to maintain a constant 30mph.

with it running, spray wd40 around the inlet manifold where it bolts to the head, if normal idle is restored then that would be your problem

But i think with the blue smoke issue, it must be something else. Perhaps worth investigating breather pipes from crank case and the pipe that goes from low down on the block to the underside of the inlet manifold.

Ask JAMZ, he's just had a load of grief replacing this part as it is a fanny on to put back together.

Smoke on startup etc, usually valve stem seals

Smoke when blatting it and on overrun is usually piston rings I think

[maxfield]

I thought it was just piston rings when oil was burning but you learn something new everyday

[Dan318-is]

Blue smoke normally means its burning oil and pistons rings are gone.

Not always young one, stem seals can also be kaput.

[Sparkysparks]

Hi, my 318is does this, the rubber boot between the intake and air filter is well cracked though, BMW have had one on hold for me for about 6 months now, im hoping this will cure it, although ive been advised to get another idle control valve, but i dont wanna pay £80 for something smaller than my middle finger, and i cant find a second hand one that fits my car.

[E30BeemerLad]

get a used one, I flogged my spare one for £15
put a wanted ad up, plenty of people breaking cars at the moment

[Morat]

ack, drove it home from work - took about 30 minutes. 5 minutes cross country to the A-road, 15 minutes on that and 10 minutes through York.
By the time I got home it was hardly running at all. It would die at idle, it wouldn't rev, kept dropping out cylinders and cutting out altogether. Its weird, if you rev it up it seems to clear and run normally for a few minutes and even idle properly. Then it starts playing up again. I'm not going to drive it anymore till the blue temp sensor is replaced and then it'll be a test drive cos right now its dangerous

[Morat]

Well it wasn't the blue temp sensor - it turns out that the MAF sensor had a dry joint and was giving the wrong reading to the ECU. It has been cracked open, repaired and glued shut again. Once its dry I'll be able to have a test drive and see.

Here's hoping!

[E30BeemerLad]

do you live in/ near York then fella?

What colour is your chariot?

[320Touring]

Hi, my 318is does this, the rubber boot between the intake and air filter is well cracked though, BMW have had one on hold for me for about 6 months now, im hoping this will cure it, although ive been advised to get another idle control valve, but i dont wanna pay £80 for something smaller than my middle finger, and i cant find a second hand one that fits my car.

dude-the iS one is the same as fitted to the 318i m40 limp-plenty of them in scrappers-"borrow" a few, can of carb cleaner and bobs your mothers brother

Fingers crossed Morat

[Morat]

do you live in/ near York then fella?

What colour is your chariot?

White, if you can see past the smoke
I live off scarcroft road, and someone has a very tidy dark blue touring K reg nearby - is that you?

[E30BeemerLad]

No not me mate, I live in Haxby

[massive]

Well it wasn't the blue temp sensor - it turns out that the MAF sensor had a dry joint and was giving the wrong reading to the ECU. It has been cracked open, repaired and glued shut again. Once its dry I'll be able to have a test drive and see.

Here's hoping!

How did you find this out?

[Morat]

I didn't - but I'll ask the man who did it.

edit:

He has an autodata CD which tells him the readings he should get off the various components and also what the ECU should be saying. He checked it out and the air flow meter was playing up. Didn't solve the problem tho

[Sparkysparks]

Hi, my 318is does this, the rubber boot between the intake and air filter is well cracked though, BMW have had one on hold for me for about 6 months now, im hoping this will cure it, although ive been advised to get another idle control valve, but i dont wanna pay £80 for something smaller than my middle finger, and i cant find a second hand one that fits my car.

dude-the iS one is the same as fitted to the 318i m40 limp-plenty of them in scrappers-"borrow" a few, can of carb cleaner and bobs your mothers brother

Fingers crossed Morat

Cheers buddy, i takeit your talking about the ICV, ill have to look into that.