Solution to Fuel Gauge/Sender problem

[bonbon]

Has anyone considered changing the fuel cap to a vented one in order to avoid creating a vacuum in the fuel tank which collapses the tank wall and can cause the notorious damage the fuel sender?

 

[NZ00Z3]

Isn't there an evac valve that is used to detect leaks in the fuel system that pops up a warning light? Or am I thinking of E46's?

 

[bonbon]

I hope not. I’m banking on this being a solution to overcoming Vac in the tank.

 

[NZ00Z3]

Easy way to test it, don't fit the fuel cap properly, leave it loose. See if any lights pop up.

I know a loose cap will pop a light on the E46's, just can't remember about the Z3's.

 

[137699]

Surely a vented fuel cap is just going to lead to a strong smell of fuel outside of the car & a potential fire risk?
No way that would pass an MOT here in the UK.

 

[DomiMik]

Has anyone considered changing the fuel cap to a vented one in order to avoid creating a vacuum in the fuel tank which collapses the tank wall and can cause the notorious damage the fuel sender?

Counter question: why not simply change the charcoal filter which is the main cause for the problem? When I started to notice the first signs of vacuum in the fuel tank, I bought a new filter and replaced the old one, shouldn't take more than 20 minutes. The old one lasted 20 years, so I think that's a simple and not too expensive solution
(~ £ 110).
After all this will eliminate the problem, a vented fuel cap only eliminates the symptoms.

 

[vetinari]

I had an engine warning light pop up last month on my 2001 3.0i . The problem turned out to be a loose fuel cap . I don't think a vented fuel cap is the way to go .
Vetinari

 

[bonbon]

I don't think a loose cap, and a cap with a one-way-valve is the same.
1. It's surprising that your light was triggered with a loose cap. I now disconnected the charcoal filter and no light was triggered....
2. I thought the problem was a faulty release valve and not a blocked filter. Either way - it's an embarrassment to BMW how many millions of dollars they made on replacing sender units.

 

[Nodzed]

The Z3 has a anti vac valve already fitted, if you have a vacuum issue I would say its failed.