Sorry not E30-related but I know there is a lot of good knowledge on here so thought I'd risk popping this question in here...mod's move if inappropriate.
For a while now I've had a high-idling E34 520i. Checked/changed lots of stuff to no avail.
One item I changed - albeit for a used replacement - was the fuel tank breather valve. My original one was ticking. The new (used) one ticked also. Could it be I've been unfortunate with the replacement and have two faulty valves or might it be a wiring/signal issue to it? Obviously I'm hoping that this valve is sticking and allowing un-metered air past the throttle body....
E34 M50 Fuel Tank Breather Valve Question...
Moderator: martauto
I have at the moment an m50b25 tu from an e34 525 in my car and when plugged into live data it showed up fuel tank vapour or purge valve..... I've been told by a reliable source on here that the engine will run fine without this and there is no need to have it!
The e34 will have a carbon canister and purge valve and I know when fitting to an e30 shell this can be done away with and have no effect on the running of the engine
Hope this helps
Ant
The e34 will have a carbon canister and purge valve and I know when fitting to an e30 shell this can be done away with and have no effect on the running of the engine
Hope this helps
Ant
A 2 door e30 with 8 cylinders, what could be better 
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Ednamillion
- E30 Zone Newbie
- Posts: 53
- Joined: Sun Sep 10, 2006 11:00 pm
Cheers Ant.e30-dk wrote:I have at the moment an m50b25 tu from an e34 525 in my car and when plugged into live data it showed up fuel tank vapour or purge valve..... I've been told by a reliable source on here that the engine will run fine without this and there is no need to have it!
The e34 will have a carbon canister and purge valve and I know when fitting to an e30 shell this can be done away with and have no effect on the running of the engine
Hope this helps
Ant
So I could by-pass the valve entirely? Hook up the hose in and hose out together?
Well on my e30 I had 3 fuel pipes....
1 fuel supply
1 fuel return and 1 fuel vapour
Obv the supply and return go to the fpr and fuel rail and the vapour pipe gets poked out through the turret...
I would say it would be fine to do this but just wait for someone to confirm mate, on my loom I have the plug for fuel tank vapour or purge valve but this is left unplugged and my engine's been fine
1 fuel supply
1 fuel return and 1 fuel vapour
Obv the supply and return go to the fpr and fuel rail and the vapour pipe gets poked out through the turret...
I would say it would be fine to do this but just wait for someone to confirm mate, on my loom I have the plug for fuel tank vapour or purge valve but this is left unplugged and my engine's been fine
A 2 door e30 with 8 cylinders, what could be better
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Ednamillion
- E30 Zone Newbie
- Posts: 53
- Joined: Sun Sep 10, 2006 11:00 pm
Just looking at this here http://mysite.verizon.net/vzerdcib/e34a/id7.html if the schematic is correct might bypassing the valve not create/allow a continuous vacuum leak I wonder?
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
Disconnect the vapour hose from the rear of the car that connects to the carbon cannister, and tuck the free end of this hose into somewhere out of the way, such as a hole in the chassis rails.
This hose must be left with its end open.
Disconnect the hose that goes from the valve to the inlet manifold, at the valve end, cut the hose as short as is practical, and find something to blank it off with. This hose must be blocked.
Remove the hose between the valve and the cannister and the cannister themselves, and bin them.
The valve should be cable tied somewhere convenient, and the electrical connector left in place, otherwise the ECU will throw a fault code and switch on the ECU warning light, if fitted, although it won't cause running problems.
BMW actually do a resistor to replace the valve, that was intended for markets where the emissions stuff wasn't required.
I've removed this stuff on a few E34s and 36s that I have, mainly to give a bit more space under the bonnet.
This hose must be left with its end open.
Disconnect the hose that goes from the valve to the inlet manifold, at the valve end, cut the hose as short as is practical, and find something to blank it off with. This hose must be blocked.
Remove the hose between the valve and the cannister and the cannister themselves, and bin them.
The valve should be cable tied somewhere convenient, and the electrical connector left in place, otherwise the ECU will throw a fault code and switch on the ECU warning light, if fitted, although it won't cause running problems.
BMW actually do a resistor to replace the valve, that was intended for markets where the emissions stuff wasn't required.
I've removed this stuff on a few E34s and 36s that I have, mainly to give a bit more space under the bonnet.