Rough Idle - Cold Start

Disca

Zorg Addict
British Zeds
Joined
Aug 25, 2016
Points
45
Location
Uxbridge, UK
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Z3 2.8
New week, new posts trying to work out what bits and bobs are so I can decide when to resolve them!

When cold starting my 2.8 it tends to have a bit of a rough idle as the warming up process moves through its stages. As the revs start to drop down the engine has a couple of splutters, not stalling though, and then runs as normal. Then as it warms to normal idle level it may have a few more.

Doesn't feel like anything is out of the ordinary when driving, however I don't have a baseline to define what normal is at this point in time. I get the occasional minor shudder at traffic lights but nothing that moves the rev needle, which the cold start drops do.
 

mwpe

Zorg Guru (V)
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178
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Camberley
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3.0
I would recommend using a code reader before you start changing expensive parts.
 

Disca

Zorg Addict
British Zeds
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Uxbridge, UK
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Agreed, need to find one of those first!
 

Faheem

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I recommend this
https://www.amazon.co.uk/CAN-Bus-Trouble-Diagnose-Diagnostic-Scanner/dp/B001CBBY7O

along with this adapter

https://www.amazon.co.uk/OBD2-Femal...g_3?ie=UTF8&psc=1&refRID=T4HS3XSY6X03JZWQX2F0


Alternatively instead of buying an adapter - buy this - this is an airbag reset tool (which will prove to be very useful - and it will come with an adapter
http://www.ebay.co.uk/itm/Airbag-Re...767206?hash=item3f64a976a6:g:hVQAAOSwVL1V~o6x

But I had a similar issue and it turned out to be the camshaft position sensor. Do you find that your car is using excessive amounts of fuel?
 

Disca

Zorg Addict
British Zeds
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Points
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Location
Uxbridge, UK
Model of Z
Z3 2.8
I've only had the car a couple of weeks. So not to sure what is counted as excessive.
I've had an indicated average over the two weeks of 28.3 however I do alot of motorway driving and run the car as a daily, 70 miles a day.
 

Disca

Zorg Addict
British Zeds
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Uxbridge, UK
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Ordering the airbag reset tool as we speak also :) Thanks for the link
 

Lee

Zorg Guru (V)
British Zeds
M Power
#ZedShed
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Points
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Location
Basingstoke
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Z4 Coupe 3.0si
Check all the rubber hoses if you haven't already.

The 2.8 has a feed to the Idle control valve from the back of the boot hose. If there's a split it gets really lumpy.

Lee
 

Disca

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Hi Lee

that means nothing to me :(
 

Lee

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Hi Lee

that means nothing to me :(
I'll explain.

The air box that holds the air filter is attached to a rubber hose heading towards the inlet manifold. (Think its the only rubber component)

Check all around that rubber hose for cracks, specially under it.
 

Disca

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Thank you for elaborating, I will have a check when home tonight, unless I find a spare 10 minutes at work later and it stops raining :)
 

Disca

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Is it best to take the hose off to examine it properly or can you do it quite easily in situ?
 

Lee

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Best to take it off. You can do this with just a flat blade screw driver. Very basic DIY, feel free the unplug the MAF sensor between the airbox and that rubber hose.
 

Disca

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I've managed to take the cat off my motorbike and fit a new exhaust, so hopefully a flat blade screwdriver might be something I can manage :D
Using the bike to improve my capabilities however always scared of messing the car up lol. Think it might be a job for the weekend if im taking bits off!
 

Lee

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I've managed to take the cat off my motorbike and fit a new exhaust, so hopefully a flat blade screwdriver might be something I can manage :D
Using the bike to improve my capabilities however always scared of messing the car up lol. Think it might be a job for the weekend if im taking bits off!
This is less than a 5 min job. :)
 

roadvoyager1

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Shotley Bridge
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2.8ltr
Mine was only visible with the hose removed and concertina section expanded. So best to take it off and have a good look.
 

Disca

Zorg Addict
British Zeds
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Points
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Uxbridge, UK
Model of Z
Z3 2.8
This is less than a 5 min job. :)
I'll see if I find time then, was more thinking about the light disappearing as I'm not back till 6:30 usually and then dinner etc get in the way.
 
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Disca

Zorg Addict
British Zeds
Joined
Aug 25, 2016
Points
45
Location
Uxbridge, UK
Model of Z
Z3 2.8
Upon further inspection today, I have cracked hoses.
Now I need to work out the part numbers...
 
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