Hi, First post, sorry if this is a common fault.

Have diesel smell in cabin when car has sat for a few days. Clears after good run but when foot down car emits a smokescreen.

Been told this maybe a problem with diesel return pipe. Any ideas, suggestions?

2007 Focus 1560cc TDCi

Are system cleaners such as Wynn's or STP worth using?

Kind Regards

Brian

Has done 150K miles.

Many apologies if this is a common fault or I have not provided enough information.

Otherwise I guess no one has any ideas.

Would appreciate any comments.

Hi Brian,

This is an unusual fault and seems like it may be two separate issues.  A raw diesel smell in the cabin?  And partly burnt diesel creating smoke from the exhaust?

First thing to do is remove the engine cover and have a look at the injectors.  If you see anything wet around them that's likely to be a diesel leak, potentially from the return pipe.  And anything black and sticky is likely to be an injector seal leak from the cylinder, which also causes a chuffing noise.

Also check whether the small oil breather pipe from the cam cover is broken.  They leak oil vapour which smells awful and can be confused for diesel.

And lastly check whether you can see any exhaust gas escaping around the turbo and DPF at the front.

If that all checks out ok then we can move onto a potential exhaust smoke fault instead of a cabin smell fault.

Very much appreciate your comments. Will take cover off and check it out.

It was a faulty / leaking injector number 4 cylinder. Now replaced all is fine. Increased power and no more smells.

Thanks Tom

On 5/8/2024 at 8:11 PM, TomsFocus said:

First thing to do is remove the engine cover and have a look at the injectors.

Tom, your capacity for remote diagnosis never ceases to impress! 😀

On 5/5/2024 at 2:53 PM, BobHellraiser said:

Hi, First post, sorry if this is a common fault.

Have diesel smell in cabin when car has sat for a few days. Clears after good run but when foot down car emits a smokescreen.

Been told this maybe a problem with diesel return pipe. Any ideas, suggestions?

2007 Focus 1560cc TDCi

Are system cleaners such as Wynn's or STP worth using?

Kind Regards

Brian

This is a late reply, but it may help someone down the line.

 

I had a diesel smell in the cabin. It was caused by blow-by of injector seal. After just tightening the injector, it fixed the problem.