Fuel Tank popping?
Discussion
Another Imperial Blue Chimeara owner. Had the car four months and get a pop from the fuel tank when it is half empty or less and the fuel pump first start up.
This appears to be due to pressure build up and the tank "inflating". Is this normal ? Has anyone else else experienced this ?
This appears to be due to pressure build up and the tank "inflating". Is this normal ? Has anyone else else experienced this ?
i used to get this when i first had my current griff.for me it was the leven filler cap which is a bad design and has no vent in it.i ended up putting a vent in it which is invisible,rather than drill a hole straight through it which water can pass through.never had the problem since.
Big Al. said:
Could be that if the tank is not venting properly, that the carbon canister breather in the front passenger wing is blocked.
Yep.. sounds just like the symptoms of that
Its the tank "deflating" rather than "inflating" though as the fuel drains out of it and lowers the pressure inside.
Cheers
Matt.
Edited by M@H to add: Mongoose.. sounds like your canister was blocked too, there should be no need for any holes in filler caps
>> Edited by M@H on Thursday 5th May 10:18
M@H said:hi Matt.i did wonder that.the car had done less than 6k miles at the time though,so i couldnt geuss why it should be blocked?the telling bit came when i replaced the leven one with a std one and the problem dissapeared!most caps have some sort of vent built in,but when you look at a leven cap,theres no possible vent until you modify it.ive also found great variation when it comes to putting fuel in the tank.first chim was v.difficult,first griff was superb,tuscan was ok,new griff is like first chim!!i wonder if the pipes are being twisted or pinched a bit out of sight and hence inner cross-sectional area is being reduced?
Mongoose.. sounds like your canister was blocked too, there should be no need for any holes in filler caps
Moved around a bit, and changed between integrated & separate purge valve. Trusty Rover 400/200 are suitable replacements (same as on my LR anyway).
When you get it off, make sure that the vent pipe is clear, this can be trapped against the chassis, its the one that goes parallel with the rad bottom hose, follow this & you will find the carbon can / purge valve.
Dave
When you get it off, make sure that the vent pipe is clear, this can be trapped against the chassis, its the one that goes parallel with the rad bottom hose, follow this & you will find the carbon can / purge valve.
Dave
mongoose said:
i used to get this when i first had my current griff.for me it was the leven filler cap which is a bad design and has no vent in it.i ended up putting a vent in it which is invisible,rather than drill a hole straight through it which water can pass through.never had the problem since.
FACT 1 - To meet Type Approval no fuel system is allowed to vent to atmosphere.
FACT 2 - The TVR original cap does not have a vent hole.
FACT 3 - The system when operating correctly collects the fuel vapour in the 'carbon canister'. When the car is started a valve opens which purges the canister and allows the vapour into the engine and is burnt off.
FACT 4 - When the cainister or pipe work becomes blocked the fuel pump will create a vacuum. Opening the fuel filler cap releases this with the 'hiss' and/or 'bong'of the tank returning to normal.
The Leven cap, as per the TVR original does not have a vent hole and so is not a bad design. The problem is with the car not the cap!
leventech said:appologies,didnt intend to cause offence!it must be that the original cap that i used had also been modified then.i do think its a nice cap otherwise-honest
mongoose said:
i used to get this when i first had my current griff.for me it was the leven filler cap which is a bad design and has no vent in it.i ended up putting a vent in it which is invisible,rather than drill a hole straight through it which water can pass through.never had the problem since.
FACT 1 - To meet Type Approval no fuel system is allowed to vent to atmosphere.
FACT 2 - The TVR original cap does not have a vent hole.
FACT 3 - The system when operating correctly collects the fuel vapour in the 'carbon canister'. When the car is started a valve opens which purges the canister and allows the vapour into the engine and is burnt off.
FACT 4 - When the cainister or pipe work becomes blocked the fuel pump will create a vacuum. Opening the fuel filler cap releases this with the 'hiss' and/or 'bong'of the tank returning to normal.
The Leven cap, as per the TVR original does not have a vent hole and so is not a bad design. The problem is with the car not the cap!
I've been told my several people that a SLIGHT pressure build up is normal even with a working carbon canister and purge valve. I've also been told that a faulty purge valve shows up as an ECU fault code (I think by Mark Adams).
The "fix" to the boing noise is to give the fuel tank a hefty kick in the middle. This prevents the side of the tank from flexing when pressurising/de-pressurising.
Ian A.
The "fix" to the boing noise is to give the fuel tank a hefty kick in the middle. This prevents the side of the tank from flexing when pressurising/de-pressurising.
Ian A.
Had my Chim for a dozen years or so now and have just put up with the fuel tank popping all the time - even with the fuel cap only loosely in place! (Otherwise i couldnt get it off to fill up because of depressurisation). Finally decided to research the problem and low and behold here is my answer. Thanks guys - I can set about fixing it once and for all now.
mongoose said:
appologies,didnt intend to cause offence!it must be that the original cap that i used had also been modified then.i do think its a nice cap otherwise-honest
Why would anyone buy a Leven fuel cap ? Its not on the outside of the car so you can`t admire it ! just seems a waste of time .If the roll over is stuck closed could that be the problem ? Mine does not have a carbon canister ,just a very small breather tie wrapped to the side of the diff ,mine still does it .
Edited by SILICONEKID345HP on Monday 23 June 22:31
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