Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Gintonic]

Hello its me again. Hope i m not too much boring with my omega , it behaves like a  citroen
V6 3.0 FL. manual LPG
In the morning idles very rough like a spark plug missing , on low revs, on high I think not
When I open the petrol tank cap, it produces sound like some kind of pressure release, air comes out under pressure , dont know if thats normal or not
In the recent past vacuum hose from purge valve was disconnected on both sides so I connected it , thanks to guys here , from the forum
All of this happens when running on petrol , when on lpg car runs very very normal

[MonzaGSE]

Dont think its pressure in the tank. Its probably vaccum. Air rushes in to the tank when the cap is opened. The fuel pump on one of our estates sucked the tank flat when the tank venting system failed. As a test and temporary solution try running with the fuel cap loose. Just fasten it enough so it wont fall of but not so much that it seals. If problem dissapears then you got a problem with the venting/purge system for the tank.

[Gintonic]

How do you solve the problem?. What element fails, so it can be repaired or replaced.

[Doctor Gollum]

Purge valve or carbon canister. Both relatively cheap to replace 

[Gintonic]

Ok I guess purge valve is under the front right arch and canister is on the opposite side of the hose
Is there any danger to drive it like this. I mean the pressure build in the fuel tank?

[BazaJT]

It's the other way round,charcoal canister is in wheelarch with the purge valve being behind the right hand cylinder head.Try Monza GSE suggestion of slightly loosening the petrol filler cap as this will allow air into the fuel tank.Not had a plastic tank sucked flat by vacuum but have had a metal one do so and it didn't half go with a bang!

[Gintonic]

Sorry I didn't quite understand, it can blow  or something?
Have no idea if my tank is metal or plastic

[Keith ABS]

 Plastic tank on Omega B

[MonzaGSE]

Tank is plastic. And it wont blow as its no pressure in it. Its vaccuum. If the venting system dont work there wont be any air going into the tank as the petrol pump sucks petrol out. This will cause a vaccuum and the tank could cave in in the middle as the pump keeps sucking fuel. Releasing the petrol cap will allow air to enter the tank as the pump sucks fuel out. Very doubtful that the tank will actually break as the pump will eventually give up when the underpressure gets to strong. In my case filling the tank back up made it pop back into its original shape. 

[TheBoy]

Whats it like on petrol?  LPG demands more of the ignition.

[Gintonic]

Monza, thank you for your explanation, I have an lpg system so the car runs on petrol very short time,  but the pump works all the time, maybe I should put a switch or something to manually turn it off when driving on lpg
Theboy, problems occure when driving on petrol, on LPG is totally fine. Yes it does affect the ig ition, so it must have new plugs, leads and coil all the time

[Gintonic]

Well, you guys know your stuff, yesterday I left the fuel cap loose, this morning car starts perfect, so it's a problem that you all predicted, thank a lot, I will deal with it some how, for now I have good start on petrol, which is very important since winter is in the doorway here, we are talking about - 20 Celsius if we are lucky

[Doctor Gollum]

You can test the purge valve by applying 12v and blowing through it. No blow through, no worky.

If it tests clear, then you need to replace the charcoal canister behind the front right wheel arch 

[Gintonic]

Well, Dr Gollum, as you said, no blow through the plastic pipe when ignition on. So I guess next step, purge valve. I won't even ask is it hard to change,  as I cannot see it at all. So if someone has any experience with this please share, at least a picture of it so I ll know what to look for
Thank you

[Doctor Gollum]

Well, Dr Gollum, as you said, no blow through the plastic pipe when ignition on. So I guess next step, purge valve. I won't even ask is it hard to change,  as I cannot see it at all. So if someone has any experience with this please share, at least a picture of it so I ll know what to look for
Thank you

You misunderstood me... The ecu applies 12v under particular circumstances, ignition on not being one of them...

Apply twelve volts to it directly and report back