W124 300e - petrol fumes

[theRéhann]

I have a fair idea that this problem is being caused by blocked breathers somewhere, but expert advice would be greatly appreciated...

The car runs fine, but intermittently, mostly after driving for quite a while, you can smell petrol fumes. When you open the fuel filler cap, there is a "whoosh" sound, showing a vacuum being formed in the tank.

Would I be able to clean the breathers, wherever they are?
Is it just a cleaning job, or is this major surgery?

The car has done 230 000 kms (142 000 miles), so I'm not to surprised about the amount of attention the car needs.

Any expert advice most welcome!
469

 

[Bellow]

Would I be able to clean the breathers, wherever they are?

If your car is thus configured, this may help.

 

[theRéhann]

Thanks, I have seen that graphic.

With my limited technical knowledge, I am thinking the lines at number 4 must be the culprits?





1369

 

[hotrodder]

A 'whoosh' when the filler cap is removed is normal. 47 Fuel system - M103 47-0030 goes into a bit more depth about the tank venting system, while 50 mbar (~0.725 psig) doesn't sound like much that's the equivilant of around 30 litres of air escaping if a 70 litre tank has 10 litres of fuel left in it when the cap is removed...

The diaphragm (#4) is less of a suspect than a blocked charcoal canister or a leak in one of the evap hoses (or a leak elsewhere) imo. The charcoal canister isn't servicable, they are scheduled to be replaced once in a blue moon (every 72k miles/4 years according to the service book for my 320) but often aren't as they're tucked away behind the wheel arch liner inbetween the inner & outer wing and usually last a lot longer than the service schedule suggests. They cost around £50 but obviously won't fix things if the problem is a leak at one of the hose connections anywhere in the fuel and/or tank venting system etc

 

[theRéhann]

Thank you very much, I appreciate the advice!



194

 

[theRéhann]

Update: It seems like the problem is actually related to worn injectors that leak.

I should've known better, because the car does "flood" after a short trip...

Got a quote from an independent workshop specialising in Benz for replacement of all six injectors, seals, labour etc for ZAR6 500 (about GBP360).

How does that compare to what you would pay in the UK?






211

 

[ray_hennig]

Update: It seems like the problem is actually related to worn injectors that leak.

I should've known better, because the car does "flood" after a short trip...

Got a quote from an independent workshop specialising in Benz for replacement of all six injectors, seals, labour etc for ZAR6 500 (about GBP360).

How does that compare to what you would pay in the UK?


211

The injectors for yours are about £30 each, unless you have the M104 twin cam engine, in which case they're about double that. Seals and guides maybe another £50 making something like £230 to do it yourself.

I did this job recently on the M104 and it was well worthwhile. However, there was never any fuel smell - any leakage was internal and burnt off on start-up.

Have you checked the EHA on the fuel distributor? These are notorious for leaks, either the grommets (very cheap) or the EHA itself (not very cheap). Worth checking perhaps.

Good luck.

RayH

 

[anfieldassasin]

Hey might not be useful but in my 1990 230ce m102 engine, I had the same problem. Start with the simple things, for me this was the fuel filter leaking at the back which still caused a strong smell of fuel in the car, also as has already been suggested the EHA valve can leak either through worn o-rings (cheap fix) or the valve body it's self being cracked (expensive fix), in my case the screws holding it to the fuel distributor were loose!

I changed the 4 injectors on my m102 took about 30mins, original bosch injectors were £22 each plus seals were £1-2 each (from germany, pm me if you want the website address unless I'm allowed to post it here). The 300e is an m103 right?? Why not have a go at replacing them your self?

Bw
Sam