Fuel Tank Venting Problems
08-06-2015, 09:23 AM
#1
Wahay!! I've lost my Virginity!!
Thread Starter
Fuel Tank Venting Problems
I haverecently replaced the fuel tank on my sierra cosworth 4x4 with this aftermarkettank:
Afterreplacing it, I had trouble filling it as the petrol filler kept clicking (i'mguessing because the tank was not venting properly) unfortunately I onlyrealised this at the start of a 350 mile round trip so had to drive the car anyway.
To cut a longstory short my fuel pump has now failed and the car is broken down on my matesdriveway. I have dropped the tank and the vent pipe to the top of the tank wasnot blocked so I’m hoping I had just twisted one of the pipes or one of thepipes was squeezed shut by the fuel tank.
One issue Ihad when fitting this tank was that the fitting for the vent pipe whichconnects to the filler pipe was slightly smaller in diameter than the original(only by a few mill) so I don’t know if this may have caused the problem?
I am going tofit a new pump this weekend but obviously don’t want the same problem again,does anybody have anything specific to look for or had the same problem before?
17-06-2015, 09:21 PM
#2
Are you using the correct cap ?
Some cars will have a vented cap, other later stuff will vent via a purge valve back into the air inlet of the engine somewhere so any vapours dont go to atmosphere.
Some cars will have a vented cap, other later stuff will vent via a purge valve back into the air inlet of the engine somewhere so any vapours dont go to atmosphere.
17-06-2015, 10:15 PM
#3
from memory:
the sierra tanks had 3 pipes going in plus the hole for the fuel to come out of
one pipe is to fill up the tank
a second smaller pipe runs up along side this so that when you are filling up the air is rushing out
then there is a third one, tiny one, that is the vent to atmosphere that runs along the seam halfway up the tank
the sierra tanks had 3 pipes going in plus the hole for the fuel to come out of
one pipe is to fill up the tank
a second smaller pipe runs up along side this so that when you are filling up the air is rushing out
then there is a third one, tiny one, that is the vent to atmosphere that runs along the seam halfway up the tank
18-06-2015, 12:13 PM
#4
Wahay!! I've lost my Virginity!!
Thread Starter
I dropped the tank on Saturday and found that the carbon filter on the smallest vent pipe was blocked (couldn't blow through it either way). I am under the impression that this is the vent pipe for allowing air into the tank when the car is running (with the small pipe on the filler neck being for venting during filling only). I took this filter off so that the tank now vents straight to atmosphere (i'm assuming this filter is only there to protect the environment and serves no mechanical purpose).
I have also replaced the fuel pump and wiring and the car is now running sweet as a nut so I'm hoping this is problem solved.
I haven't filled the car up at a petrol station yet so I'm not sure if my filling problems have been fixed by doing this as well. I have read on the internet that some cars have problems with venting during filling (MGTF's and Porsches) so I'm not sure whether this could just be down to poor tank design (thanks to my cheap aftermarket tank) or whether I still have more work ahead of me.
I have also replaced the fuel pump and wiring and the car is now running sweet as a nut so I'm hoping this is problem solved.
I haven't filled the car up at a petrol station yet so I'm not sure if my filling problems have been fixed by doing this as well. I have read on the internet that some cars have problems with venting during filling (MGTF's and Porsches) so I'm not sure whether this could just be down to poor tank design (thanks to my cheap aftermarket tank) or whether I still have more work ahead of me.
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