The last straw - smell of petrol

[Dano]

My troublesome W208 it at it again. The misfire although not fixed, was examined by MBTech in Warrington who said I could probably live with it.

Since I had the car back there is a strong smell of petrol in the cabin. I don't notice it when driving at speed, but when I slow or stop (at traffic lights for example) a strong odour of petrol appears. This smell is definately unburnt fuel.

I recently had a fuel injector replaced (as part of the many fruitless attempts to resolve my engine wobble at idle) and I can't help but wonder, is fuel leaking?

A cursory examination under the hood shown no obvious or subtancial leak. I've looked on this forum and found a few hits, but none that I noticed for a CLK.

Is this smell of fuel problem a known issue on a W208? I had a fuel filter and MAF replaced in 2009. Any other suspects?

This problem, the most recent in a long string of problems, has just tipped me over the edge. I am now ordering a company car.

My car, although a lovely drive, is becoming a real pain in the ass. Hoping to keep it the 3 months before my company car arrives, assuming I am not engulfed in flames before then. A sad end to my first mercedes.

-- D

 

[BlackC55]

It is probably somthing very simple like one of the rubber pipes at the fuel filter has a slight weep at the fuel senders.

Cheap to fix too if it is from there.

 

[BlackC55]

A slight miss at idle is not the end of the world. Did you try new ignition leads?

 

[Barbanasos]

Have you tried any other specialists around Manchester? As olly said it could be something very simple and diagnosed if looking at the right places.

 

[chris846]

Don't know if this could be relevant to the 320 engine, but I once had a five cylinder Audi (glory glory) that had a random 'miss' on tickover. Turned out to be a worn valve guide - the valve occasionally didn't seat properly. Soon fixed with new guides.

 

[MB TECH]

Olly a garage prior to us seeing the car has fitted, a couple of injectors, a couple of coil packs etc


To the OP If the slight mis at idle is annoying you get it back to us we will look at it.


I will add however to clarify, we have fitted no parts to this car, we merely carried out a diagnosis which returned no obvious verdict, completley free of charge.

The parts were all fitted at a garage previous to the OP bringing car to us, just to avoid confusion to the original post.

We were merely looking into the "misfire" fault.

There are very slight smooth running discrepencies on a couple of cylinders, but the "mis" is not what I would call a mis. It is just v v slighly lumpy on idle. The star machine showed no fault codes or misfires.

We find this idle on a high number of 112 engines, upon acceleration its smooth as silk.

My advice remains the same as when we looked at it. New plugs would be my first port of call.


Unfortunately there is not an obvious in your face fix to cure the slight mis at idle.

The fuel smell you need looking at immediately, however I can say whilst looking at your car, the injectors were all dry, but the fact that you had just had an injector replaced by another garage, I am concerned that the rail may not be sealing correcly. It is dangerous to continue driving with a fuel leak.


Get it into us, we can look whilst you wait and once again we wont charge you a penny.

 

[chris846]

To add to the above post - my 320 has that ever so slight lumpiness in the tickover - I wouldn't call it a misfire either. The engine is as sweet as a nut under all other conditions. Nice to know it's not considered a major fault.

 

[Howard]

Yep , my 430 has a little tiny 'miss' while it is ticking over ....

Soon as you give it any gas , it disappears.

 

[johnpidge]

I'll add that mine does as well and I have just had plugs done (16!!!!!) and minor service - oils etc - still tiny tiny lumpiness at tickover - It goes like sh*t of a shovel though!!

Smell of fuel needs sorting thats a no no!!

 

[Dano]

fixed!

For the story so far also read

Also see http://www.mbclub.co.uk/forums/engine/96093-w208-check-engine-light-misfiring-video.html

The next chapter this story involved a 3rd Garage. A mechanic my parents heartily endorse. I was going away and left the car still smelling of petrol at my parents. They promise their master machanic will fix it.

I've now had another fuel injector replaced, described as "right bank cylinder 2". I don't know which one this might be. I dearly hope this is not cylinder six as I've now paid for this twice.

He also removed, cleaned and replaced the five other injectors. An additional part fitted was new fuel injector retaining clips.

Here is the sting in the tail, although I don't have concrete proof, one of the other two garages who looked at my car recently did not replace these clips correctly. This led to the fuel leak at the damage to the fuel injectors.

Now all this work has been done the engine is running smoother than ever. In addtion to the fuel leak being fixed, the long standing engine wobble, misfire, whatever, has also been resolved.

A happy ending, but a expensive story! Maybe I'll keep my mercedes for a few more months after all

-- D

 

[Howard]

Happy days !! pleased for you mate !

H

 

[James1976]

At least it seems to be working OK now!

Say a prayer to the big man upstairs and hope it remains that way....!

 

[MB TECH]

We did not remove your fuel rail, clips or any injectors. We removed nothing at all, simply connected star machine and road tested.

So rule us out.

Glad you got it sorted, the fuel leak could have been dangerous.

 

[Dano]

I didn't notice the earlier post from MB Tech. Thanks for your work, advice and the offer of further free diagnosis.

To clarify my statement earlier on this thread, it was the 3rd Mechanic who suggested this fuel leak was due to poor craftsmanship. I formed an opinion on that basis.

No doubt you are ruled out. I would not hesitate to bring my car back to MB Tech.

As it happened the fuel leak coincided with a convenient moment to leave it with my parents; I was abroad 15/10 to 19/10.

Keep up the good work and presence on the forums

-- D

 

[jools182]

I know how you feel, my W202 has been the most unreliable car I've had

I hope the newer mercs are better

 

[johnpidge]

Glad its all sorted now!!!!!