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Greg, Shop Owner
Category: UK Car
Satisfied Customers: 7088
Experience:  17 years Shop Owner /Technician. 27 years experience,
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We have a 2006 116i (n45 engine) that was brought into us

Customer Question

Hi - we have a 2006 116i (n45 engine) that was brought into us having skipped the timing and wasn't starting. We have replaced the chain kit, VANOS solenoids and exhaust VANOS unit. Car now starts but idles horribly, occasionally bringing up multiple misfire fault codes. Cam timing has been checked & rechecked as ok. A small bit of throttle smooths out the roughness and the car drives well, just won't idle. A small spray of car cleaner into the air filter housing also smooths out the running, albeit temporarily. We're thinking it's an air leak - could anyone concur?
Submitted: 1 year ago.
Category: UK Car
Expert:  Greg replied 1 year ago.

Do a compression test as this engine is a interference engine , meaning valve to piston

will connect and may bend valves .

In your case may be just a slight bend that is causing you the bad idle but at higher revs .

so a compression test should be done and a cylinder leak down test to make sure the valves are closing fully .

Do this then please get back to me .

Rgds Greg

Customer: replied 1 year ago.
Meant to say that we have already had the head off, bent valves replaced and head dressed. Problem now resolved - defective oil separator / crankcase pressure valve in cam cover causing excess air into inlet manifold.
Expert:  Greg replied 1 year ago.

Good work good find .

Happy motoring .

Rgds Greg