It is a 2012 BMW Z4 Sdrive35is. It has 57,000 miles and the car cranks/struggles at cold starts 90% of the time. Especially when sitting overnight or starting it up after work. It has no check engine light on and no codes - it seems to crank longer when cold outside. This is a new problem and it started up fine a few weeks ago.
I replaced:
Spark plugs
Coil packs
02 sensor for bank 2 (cylinders 4-6)
Here is a video of what it sounds like:
[youtube]https://youtube.com/shorts/3dZGWO0VO0k? ... qswAVNpHov[/youtube]
What could it possibly be?
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Z4 cranking at cold start
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OnlineMr Tidy
- Legend
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- Location: North West Surrey
Z4 cranking at cold start
Welcome to the forum John. 
All I know about E89s I've learnt on here, but a wild guess might be the High Pressure Fuel Pump failing. Hopefully someone more knowledgeable will be able to help.
All I know about E89s I've learnt on here, but a wild guess might be the High Pressure Fuel Pump failing. Hopefully someone more knowledgeable will be able to help.
Coupes because stunning!
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black
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Chippie
- Senior Member
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- Joined: Tue Apr 30, 2019 9:11 pm
- Location: Wakefield
Z4 cranking at cold start
I’ve not had the problem myself but from your description I’d say HPFP as well. Welcome to the forum
E89 35is space grey Kansas coral red leather
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raymond.harper
- Senior Member
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- Joined: Sun Aug 14, 2016 12:30 am
Z4 cranking at cold start
The battery sounds healthy enough, give the car a few seconds for the warning lights to go out before you crank it
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B21
- Lifer
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- Joined: Tue Oct 05, 2021 7:15 pm
- Location: In my Banana Yellow Space Shuttle...somewhere over Southern Caledonia
Z4 cranking at cold start
In probability terms ..fuel injectors, high pressure fuel pump, low pressure fuel pump..
Does the LPFP run when you open the door for a few seconds..
To check the injectors pull a plug or two and see it they are wet..
HPFP needs data logging to see PSI reading..
Does the LPFP run when you open the door for a few seconds..
To check the injectors pull a plug or two and see it they are wet..
HPFP needs data logging to see PSI reading..
We choose to go to on with this endeavour at this time and do the other things, not because they are easy, but because they are hard…
A very modified Atacama Yellow 35is
A very modified Atacama Yellow 35is