E46 330i Idle Dip Issue - Am I Being Paranoid

Relentless81 said:
:D

I think if most people look at their rev counters on their way home tonight they will see that its quite normal in any brand of car. I could be wrong though, it could be something more sinister but you will see what I mean if you are stationary, at idle and press the brake pedal or something
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Of course a bit of dipping is normal, unless you have a brand new Rolls-Royce V12 or similar. However, this is definitely abnormal. You'll be sitting there, it will be rock stable, then you'll get a little shudder as it randomly drops to 500 RPM, then just raises back up... and it would seem nothing has happened to cause it to cause it.
Oxide™ said:
I'm hoping it doesn't happen again and it's nothing to be concerned about, will have to see how it goes
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Unfortunately, you're right - it could be any number of air/vacuum related things. Even more unfortunately, unless it was caused by you loading the engine too much at once (like the pusher fan, AC compressor, lights, radio etc. all suddenly draining a lot), it will probably happen again :(
 
Someone mentions here that getting the DME software updated to v24 or above by a BMW dealer may fix this?

What other benefits does updating this have? how can I tell what version mine has? I suspect I need a Peake diagnostic reader?
 
Car was serviced last Friday by a well recommended indi with a clean bill of health but since then I have noticed odd things this week driving to work :( am I being paranoid?

Monday morning: cold but not frosty
Started car and it idled very lumpy/shuddery for the first time ever
thought I'd give it 15 secs to see if it would smooth itself out
15 secs later the engine light appeared - immediately turned car off
30 secs later switched car back on and all was as normal - drove to work and back perfectly fine
Was thinking ok, it's just a one off

This morning: cold and frosty
Started car and it idled high at around 1000rpm - which is normal when I first turn it on in the cold, it soon goes back to 700rpm
This time it didn't and driving to work it always idled at 1000rpm and only settled at 700rpm when I got to work. (~7 miles)

Been reading about the issues and it sounds like it's most likely the DISA and/or ICV?

Will check how it is driving home and tomorrow morning but it's just odd these things happen the week after a full service :confused:
 
You can check the DISA valve yourself to make sure its not broken or stuck/sticking - its not too much of a job to unplug and reinsert (iirc you need to remove the air box to make access easier). Having said that, the intermittent nature of your problem could in itself rule it out.

The previous owner of my car had the DISA valve replaced for lumpy running but in that case it was a continuous problem with the addition of slow pickup on acceleration rather than an intermittent one like yours.

I had lumpy idling on mine once which caused the engine management light to come on - engine off, engine on = all good. Start the car up next day same symptoms wouldn't go away - turned out the be the ECU!

It could be all manner of things - do you have a diag tool to read codes? What exactly was done at the service?
 
I don't have a diag tool but maybe it's time to get one (read the peake research is a good one for BMW's, can't afford carsoft)

It had an MOT, Inspection I, replaced front brake lines and Final Stage Resistor
 
[TW]Fox;18007968 said:
It's probably the icv..
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Ok, I watched some youtube clips so I reckon I can clean them both myself, I just need some carb cleaner (brake cleaner, throttle body cleaner, I think they all the same as far as I can gather)

[TW]Fox;18007968 said:
Still wondering why you paid that guy 500 quid.
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Please not this again :p
I already feel hard done by without having to remember if I was shafted on price as well. How else was I supossed to get my car back.
 
Neither the DISA or ICV have the rattle noise symptoms though - aaarg if only I knew about mechanicals, I spend most of my time worrying and researching about some impending disaster that may or may not exist and lack the knowledge and tools to just fix it myself
 
Oxide™ said:
lol ok it was around 70mph in a 60mph zone. Don't want to push it more as that would be illegal and all ;)

Thanks for all the suggestions guys, reading that thread I linked to it seems it could be a whole manner of things, like vac leaks, ICV, CCV, CPS, O2 sensors, AC? etc.

I'm hoping it doesn't happen again and it's nothing to be concerned about, will have to see how it goes
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I thought that road was changed to 40mph? Addington Rd A2022?
 
Drove home and everything was running as normal, I'll monitor this tomorrow morning as it appears to only happen then :confused:

*clutch straw*
Only thing I can think of is I was off Monday (in case repairs took longer) and unscrewed the cd changer in the boot to check if it has the correct connection for an intravee. I didn't unplug the battery beforehand, I didn't disconnect anything on the changer so I'm sure this wouldn't have caused some sort of electrical issue

pcoltrane said:
I thought that road was changed to 40mph? Addington Rd A2022?
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It was on this section of Brighton Road on the A217 which is 60mph
 
The engine light doesnt just come on for no reason - it comes on because there is a fault with the car. Just like all your coolant vanished from the header tank...

Why did you need to unplug the CD changer to find out if it had the correct connetion for an intravee, of course it does if it has a CD changer :confused:
 
[TW]Fox;18009948 said:
The engine light doesnt just come on for no reason - it comes on because there is a fault with the car. Just like all your coolant vanished from the header tank...

Why did you need to unplug the CD changer to find out if it had the correct connetion for an intravee, of course it does if it has a CD changer :confused:
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The light came on only the once which I explained (which was the first time I switched the car on after fiddling with the changer) and hasn't reappeared.

It wasn't all the coolant, just a 300ml top up, I'm monitoring this now as I should have before.

I didn't unplug the changer, just unscrewed it, slid it out a bit and looked at what connections it had at the back (has the correct 4 and 6 pin connections)
read that some older changers had a round type connection not compatible with the intravee, knowing my luck I would have got an intravee and only then found out it doesn't fit so can tick that off the list now
 
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