E46 b3 cold start issue

m folkard · Post by **m folkard** » Sat Jul 14, 2018 5:32 pm

Hi i have a cold starting fault , when I start my B3 on a 2002 plate with 55000 miles from cold it splutters and misfires until the automatic choke goes off and then the car is fine all day.
My local BMW dealership has no clue whatsoever as to why or how to repair this fault .
Has anyone had a similar fault and knows a fix

Post by **Charles** » Sat Jul 14, 2018 8:38 pm

First up - is this a 3.3 or 3.4 engine? And what variant is it - saloon, coupe, convertible or Touring? And finally, what is the build number (located on the plaque in the cabin)?

From cold, the engine sounds rough for about 30-45 seconds before settling down. During this stage, the secondary air pump (located to the left of the engine block) should be running and forcing additional air through the system to help reduce exhaust emissions. Is your pump working as it should?

If you are able to do so, a video/sound file of the issue would be helpful.

m folkard · Post by **m folkard** » Sun Jul 15, 2018 9:00 am

Hi my B3 is a 3.3 convertible model build no 220.
I will check to see if air pump is running this morning and film my car starting .thanks for the reply .

mal

Post by **Charles** » Sun Jul 15, 2018 2:23 pm

Hi Mal,

Just in case I hadn't explained properly, here's a picture of an E46 3.3 engine bay showing the location of the secondary air pump:

On cold start, this pump should run for about 45 seconds or so and you will clearly hear (and feel if you put your hand on the top) it running. The engine will sound loud and rough during this phase with revs about 1250 rpm. After about 30 seconds, the revs will start to drop to about 1000 rpm but the pump will still be running. Once the pump cuts out, the engine revs will drop to normal idle and the engine should be running smoothly.

Once we have had a chance to see/hear your video then we should be able to either reassure you or begin to diagnose another issue (hopefully the former).

m folkard · Post by **m folkard** » Sun Jul 15, 2018 4:28 pm

Hi Charles having trouble uploading video on to reply page will not add video .
There must be another place to upload pics on the ALPINA site then on to a reply page

MAL

scalesg · Post by **scalesg** » Sun Jul 15, 2018 4:54 pm

I thought this was unique to the E46 B3S

I love waiting for mine to go through this sequence and stop rumbling!

m folkard · Post by **m folkard** » Sun Jul 15, 2018 5:32 pm

This more like a misfire and rumble .
My BMW dealership was no help there solution was to completely strip down my engine at a cost of hundreds of pounds to find the cause .if they can find the cause .felt more like they didn't want to .

mal

simon13 · Post by **simon13** » Sun Jul 15, 2018 8:27 pm

is it physically starting on 4 or 5 cylinders?

My B3S is pretty rough from cold

m folkard · Post by **m folkard** » Sun Jul 15, 2018 8:41 pm

Hi Simon feels more of a fuel starvation misfire .like its trying to run . but its only for about 20seconds ,choke goes off revs settle down and then all is fine .
Trying to upload video of my b3 starting from cold could be to long of a clip.

Mal

rc944 · Post by **rc944** » Sun Jul 15, 2018 11:49 pm

please get a diagnostic test run before anything else and post the fault codes up here

generic obd readers can be cheaply bought or if youre anywhere near south bucks i can plug my inpa (official bmw diagnostic suite) into it

from what you describe it could range from nothing to a million things

m folkard · Post by **m folkard** » Mon Jul 16, 2018 9:41 am

Hi had taken B3 to my local BMW dealership in Norwich for a diagnosing and trouble shooting and the only fault found was an inlet cam sensor which they replaced .all faults cleared .
But has made no difference to the cold start bad running .Bmw acknowledge there is a cold start issue but do not know has to resolve as there is no fault code.

Mal

m folkard · Post by **m folkard** » Mon Jul 16, 2018 11:33 am

Think I will take it to another BMW dealership in Norfolk at a later date .when all this BMW recall dies down and they are less busy and able to sort my B3 starting fault .
Started this morning put my hand on the secondary pump couldn't feel it was running .Thought BM would have check that .
Cannot find a way to download video either from my phone or tablet to the website to show my car starting .

mal

rc944 · Post by **rc944** » Mon Jul 16, 2018 12:39 pm

don't you have a reputable indie near you?

if the secondary air pump was failing/failed i would have though the check engine light would have popped up on the dash? if not, then i would have expected more fault codes other than inlet cam sensor if there was a genuine fuelling issue

simon13 · Post by **simon13** » Mon Jul 16, 2018 10:13 pm

yes mine can be like this sometimes. Its also getting worse over time.

I've not tried it on my car but unplug the air pump and start her from cold see if it makes any difference. its a load of emissions bollocks anyhow as all it does is pump air into the exhaust to lessen the emissions!

E34 m5s are saddled with a similar load of air pump shite and E36 alpinas also have it

m folkard · Post by **m folkard** » Mon Jul 16, 2018 10:25 pm

Mine has also got worse over time much worse which is why I booked it in with bmw but they have no clue how to fix because there was no fault codes.
.Mal