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Matt, Mechanical Engineer
Category: BMW
Satisfied Customers: 22913
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a 2003 BMW 320ci. Every morning when I start it it starts

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I have a 2003 BMW 320ci. Every morning when I start it it starts straight away. Once I've driven it for a while and it has been off it turns over for about 5seconds before firing up then sometimes smells quite petroly. Then, the next day when it has been sitting for 12 hours it starts straight away again! Can anyone help me please?

If you haven't already then replace the spark plugs if any of them fail this checklist:

it could also be a leaking injector thats dribbling fuel into the cylinders so if the plugs are OK then I'd suggest trying a bottle of injector cleaner 1st and if that doens't help then remove the injectors and have them professionally /ultrasonically cleaned
Customer: replied 4 years ago.
Hi Matt,
Thank you for your help. I did forget to mention that I changed the spark plugs when it first started happening. What would explain the petrol smell?
I will try injector cleaner and see if that helps.
Hello James

the petrol smell woudl be unburnt fuel - hence my suggestion of new plugs

however if theyr'e OK and the injectors aren't dribbling

then it could be incorrect fuelling due to a faulty water temp sensor. If this is the problem then the ECU will not adjust the fuel correctly as the engine warms - so unplug the sensor and clean the contacts on both sides with some switch / electrical cleaner (not WD40) and inspect the wiring for any signs of damage to the insulation especially where it runs over other components and through the bulkhead- if this doesn't help consider replacing the sensor as they're not expensive
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