Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: polilara on 05 October 2011, 15:57:28
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Hello
A couple of months I have noticed a slight petrol smell in cabin perhaps only in the beginning of the journey. Fuel consumption OK (or normal) engine runs perfectly like 2.6 V6 usually does.
I understood there is a tank ventilation carbon filter behind the front right side wheel which should sometimes changed. I have now 160 000 kilometers behind. Is it possible that the smell is coming from this carbon filter ?
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There is a cabin filter, assuming you mean Pollen filter?
I tend to change mine annually ;)
I'd be looking for evidence of a fuel leak somewhere too though :-\
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Thanks for comment. I do not mean pollen filter.
What I understood is that at least "Finnish" Omegas have behind right front wheel a carbon filter which is connected to the fuel tank by a hose. Another hose or pipe is connected to the plenum or somewhere where is vacuum when engine is running. When engine is stopped all the gases from fuel tank are stored to this carbon filter. When engine is started the vacuum will suck all the gases to plenum.
Is there this kind of system an must the carbon filter be changed now and then ?
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Yes there is, I'm with you now! :-[ :-[
IIRC there is no requirement in the service schedule to change them :-\ Someone will give a definitive answer though :y
I would be more inclined to check the hoses for a tiny leak
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OK, hopefully someone will tell how often that have to be changed.
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Have you checked the petrol filter itself for leaks? Smells are like leaks, they can originate a long way from where you think they are! ;)
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there is a solenoid valve (driver side-UK- behind the plenum to the wheel side) controlling the tank ventilation.. if its donald it will block the ventilation and increase the pressure inside.. worth checking..
also the big gasket above the fuel pump may leak..
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My understanding is that the vent from the fuel tank connects to the charcoal cannister. When the car is parked any fumes from the tank are absorbed by the carbon.
When the engine is running a solenoid valve opens to the inlet manifold and the petrol fumes are drawn from the carbon cannister.
I would start by checking that the solenoid purge valve is connected and working. I would also check for damage or ageing of the petrol pipes.
My last car (a 2.5 v6) reached 200,000 miles without smelling of petrol so I think it unlikely that it would need changing unless it was damaged in some way.
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OK.
1. I will check the solenoid. Quess I should find vacuum in the pipe when engine running.
2. I will check leaks of tubes and the pump sealing etc. The pump is obviously in the tank so the sealing is above thew tank
3. Then the fuel filter itself..., never changed it. Where is it located ??
4. One stupid question, how do the tank get air when the amount of petrol is reduced ? Have this charcoal canister something to do with this thing ?
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You say that you notice the smell at the beginning of your journey. On a previous Omega I had a strong smell of petrol only after the 1st short journey of the day then nothing until the next day. This turned out to be the fuel filter. Once changed problem never recurred.
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OK, I check, where is the fuel filter ?
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This may help: http://www.omegaowners.com/forum/index.php?topic=90548.0 :y
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No leaks found.
I took the charcoal canister and its pipes away. Then I started the engine. No vacuum found in the pipe which goes to inlet manifold. I cannot even suck or blow through the pipe.
Andy H informed that there is solenoid valve which should open when engine is running. If so are there any relays or fuses to be checked. The solenoid cannot be seen. The pipe seems to go somewhere behind the manifold.
Does anyone have a photograph of the solenoid valve ? Good tips are now welcome. How to continue ? Do I have to remove the manifold to get in touch with this solenoid valve ?
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Can anyone help ?
1. Is there electrically controlled solonoid valve or not in this system, any pictures about the location ?
2. How ECU controls this valve (if it exists) ? Should it be open allways when engine running or just a couple of seconds after start. Engine is Y26SE, Motronic 3.1.1
If there is no valve at all something is just clogged behind the engine/inlet manifold. Some figures behind the engine would help a lot.
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The canister purge valve is mounted on the rear of the 1,3,5 cylinder head. It gets a vacuum feed from one of the pipes that emerge from the rear of the black "Ecotec" plastic cover on the top of the plenum. I would recommend cleaning all the passages in this cover out with carb cleaner if it hasn't been done recently as this also acts as the crankcase breather.
If you pull the pipe off the plastic housing while the engine is running you should feel a vacuum at the pipe connector.
The ECU won't always open the purge valve. I am not sure what strategy it follows but it could be that it's only vented when the engine is fully warmed up and under load, i.e. you might not expect it to be open at idle.
An in/out rush of air when you open the fuel filler cap are signs that the canister purge system is not working.
Nevertheless, the system is still sealed. You should not get a smell of petrol from the front end of the car unless something is leaking.
I would take off the plenum and check carefully for fuel leaks from the fuel lines, fuel rain and injectors, fuel pressure regulator, etc.
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Thanks Kevin, I take off the plenum as soon as I have time. Have to change thermostat at the same time, (already purchased). I never have pressure in tank.
Do you think that the purge system is closed. There are actually three pipes, one coming from tank, one going to plenum and the third going nowhere. The third one is a loose rubber pipe. I quess it is some kind of emergency channel. If purge system does not work this pipe takes care of the pressure differences. This is just a quess - I really do not know.
I can recognise the smell only in the beginning of the journey, actually in the moment when the fun of the heater starts to rotate after a couple of minutes from start (auto control). Then the smell dissappears.
OK, I continue next with cleaning all the vacuum tubes as you advised.
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I would be surprised if the purge system was the problem, to be honest. They are usually reliable. If the breather bridge turns out to be free of blockages, I would check the whole fuel system for leaks.
In particular, the plate under the boot floor where the pipes and wiring enter the fuel tank can rust and be prone to leaks.
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Thanks Kevin, I take off the plenum as soon as I have time. Have to change thermostat at the same time, (already purchased). I never have pressure in tank.
Do you think that the purge system is closed. There are actually three pipes, one coming from tank, one going to plenum and the third going nowhere. The third one is a loose rubber pipe. I quess it is some kind of emergency channel. If purge system does not work this pipe takes care of the pressure differences. This is just a quess - I really do not know.
I can recognise the smell only in the beginning of the journey, actually in the moment when the fun of the heater starts to rotate after a couple of minutes from start (auto control). Then the smell dissappears.
OK, I continue next with cleaning all the vacuum tubes as you advised.
The third pipe is presumably to allow fresh air into the carbon canister as/when it is being purged, and to equalise the pressure in the tank as the fuel level drops?
Presumably there's a one-way 'inward only' valve at this port of the canister? :-\
Have you got a picture of the carbon canister? Never seen one. :)
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buy a new petrol filler cap -- worked for me.