FARTING AND A PETROL SMELL - PETROL/VACUUM?

[NormanB]

Hi everyone ?wasn?t the weather great today!

As you may guess the weather has nothing to do with my post which is a plea for help.

Being somewhat anally retentive, when I top up with petrol I brim it (I know I shouldn?t) so that I can accurately calculate petrol consumption. What is worse is I store the data in an Excel spreadsheet!!

Anyway to my real and current problem. Last week I brimmed the tank as usual and the next morning noticed a fouging great petrol stain underneath the tank commensurate with the tank/filler overflow. So much so it had softened the tarmac drive in the affected area.  What is worse the car interior stunk of petrol and a week later still does, albeit not as strong as that first day but very - very noticeable.

I have examined the interior in way of the filler neck and tubing, had the rear wash tank out and no evidence of anything untoward. There certainly is no dripping from the tank/filler overflow.

An interesting fact, which may be associated, is that from time to time 5-10 minutes after exiting the vehicle, the old merc ?farts? or probably wheezes and the noise seems to emanate from the fuel filler lock actuator.  Sods law is I have never had the opportunity to be close to the vehicle to positively identify it ? it seems old mercs are quite well mannered and only lift ?their skirts? when they think they are alone.

I am sort of thinking there may be a connection with the vacuum system and maybe a punctured diaphragm. But I know so little (does my car have a vacuum system?) about the system I need your help.

Any help advice gratefully received.

NormanB

 

[Jim_C180]

FARTING AND A PETROL SMELL

Sorry I can't help with your problem, but you have given me a good laugh with your problem description and symptoms.

 

[giles]

FARTING AND A PETROL SMELL

Mine farts too, but that's related to the assited door closing and it's 10-15 seconds after a door/boot is closed.

Of course the expansion of the fuel as it heats up to ground level ambient teprature (as opposed to below ground storage) could have caused it.

You could have a problem with the fuel cap, I think It's supposed to let in air to avoid implosion etc, perhaps it's blocked.

Not sure that's really advise - more like ideas.

=;

 

[Andy]

FARTING AND A PETROL SMELL

Hi Norman,

The central locking system works on what I think they call a center point locking system. This means that one vacuum tube travels around the vehicle. The vacuum is introduced from a pump. This pump either sucks or blows. It gets it signal from the two front doors and boot. You mention that you suspect that the fuel cell may be causing a problem. Try disconnecting the cell. Put a screw in the vacuum pipe. You will see what I mean when you try what I am trying to discribe. If your vehicle is a estate. Its easy to find. Clearly visable on the osr towards the rear quarter glass area. Clearly designated as it has a red button on it. If its a saloon. You will have to remove or pull to the side the interior cover on the osr. Its in roughly the same area.

As for the petrol smell, first thing I would do is replace the cap. £3or 4 quid that all from the local stealership. Inspect the old one make sure the seal is good. If any doubt replace it. Check the fuel drain by the filler neck is not blocked. You will see the hole when you open the filler door. Its in the lower corner. If you pour water down the hole it should drain on to the floor. If it dosn't you could get fuel smells lingering due to the fact the fuel can't escape. There is also a breather on the tank. Usually close to the top of the tank remove the back trim in the boot on a saloon. Off the top of my head can't quite remember on a estate. Either way if you have a good rumage you should find it.

I have had on some estates the filler neck as it goes into the main tank start to rot. I doubt this is your problem. But for those of you reading this. Heres the info.

Hope this helps.

Sorry if I am miles of the mark.

Regards

Andy @ www.mercedesservicing.com

 

[NormanB]

FARTING AND A PETROL SMELL

Hi Andy
Great info (as usual).
I will check it out and feedback.
Thanks once again
NormanB

 

[csilk]

FARTING AND A PETROL SMELL

Check the fuel breather pipe for dirt and obstructions Norman.

 

[Barnie]

FARTING AND A PETROL SMELL

Hi NormanB
My car a 124/200e has always had this anomaly can be quite embarressing when parked in crowded street,
having looked into the cause quite carefully I have come to the logical conclusion that- as the tank is pressurised, a valve designed to monitor this pressure blows off as & when this pressure exceeds the valve setting. This residual pressure in the tank assists in supplying fuel to the engine. Fact or fiction?
Regards
Barnie

 

[csilk]

FARTING AND A PETROL SMELL

I must confess I suffer from the same problem, but only after a few pints and a good curry.  

 

[NormanB]

FARTING AND A PETROL SMELL

Hi Chris
If that is the case avoid being in the vicinity of a naked light!!;-)
NormanB

 

[NormanB]

Aplologies for resurrecting this old thread! ( Honest it is a sheer if not spooky fluke it is a year to the day that the last post was made in this thread).

I did all that AndyG suggested some time ago (found nothing significant). I have never had a repeat of petrol leak/smell but since that time, the old Merc continues to fart, in a discreet but nevertheless flatulent fashion.

The inspiration for posting is I just happen to be working from home this week and have not used the car since Sunday evening - yet 3 times this afternoon - there has been a distinct 'parp' from the Merc rear end.

If I could get out there at the opportune moment I could tape and attach a sound file. But the old Merc has a sixth sense and manages to nip it off while I am in the vicinity.

I do not want to start something like a 'does your car fart?' thread - but even my kids are now ribbing me about the' old mans car' and it's rather 'incontinent behaviour'.

Any?

 

[neilm]

190E flatulance

My '89 190E has a tone more like a braying donkey. Not quite so embarassing, especilly here in rural Norfolk, though I have timed it at over 10 seconds duration. It is normally accompanied by a strong smell of petrol which seems to come from under the bonnet by the air intake, but I suppose could come from the fuel pump which does seem to "hum" a bit. The noise usually occurs in warmer weather so I asssume has something to do with fuel evaporation and pressure release.

 

[neilm]

190E flatulance

My '89 190E has a tone more like a braying donkey. Not quite so embarassing, especilly here in rural Norfolk, though I have timed it at over 10 seconds duration. It is normally accompanied by a strong smell of petrol which seems to come from under the bonnet by the air intake, but I suppose could come from the fuel pump which does seem to "hum" a bit. The noise usually occurs in warmer weather so I asssume has something to do with fuel evaporation and pressure release.

 

[NormanB]

Hi Neil

Welcome to the Merc owners musical forum - perhaps we could arrange a meeting for those who have vehicles with extra-mural talents and 'ochestrate' a rendition.

NormanB