Is It Just Me ?

RustyZ4 said:
Is it just me that when im filling my Z with fuel, the petrol pump keeps stopping as if it full (even when im just starting and its pretty empty), I have to keep juggling the pump to different angles, or wait a second or two to carry on, occasionally I get a pump that only does it once or twice, but I do get it every time I fill up and in any station, not a huge issue, just wondered if anyone else has the same thing happen,
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Rusty, I'm getting the exact same issue at the moment. Did you ever find out what the problem was? I've done a search around the internet but only seem to find things about the fuel tank breather valve and a charcoal canister.
 
Beeacon said:
RustyZ4 said:
Is it just me that when im filling my Z with fuel, the petrol pump keeps stopping as if it full (even when im just starting and its pretty empty), I have to keep juggling the pump to different angles, or wait a second or two to carry on, occasionally I get a pump that only does it once or twice, but I do get it every time I fill up and in any station, not a huge issue, just wondered if anyone else has the same thing happen,
Click to expand...

Rusty, I'm getting the exact same issue at the moment. Did you ever find out what the problem was? I've done a search around the internet but only seem to find things about the fuel tank breather valve and a charcoal canister.
Click to expand...

Hi Beeacon
Nope still got the same problem, when it was in BMW they checked it out and said nothing was wrong, and as usual blamed it on the pumps!! funny enough, I had a conversation with a guy with a Z4, where we were both filling up, and he came over, saw me doing the usual juggling act, and said "im glad its not just me",,,,, the only real issue is , you never know if its full or not,
I think its common issue on a few cars and no real answer
 
As far as I can make out its got to be something to do with the pressure in the tank building up (because the fumes aren't getting to/through the activated charcoal filter). That way every time you put a little fuel in, the air pressure builds up and shuts off the pump.

If you imagine turning a bottle of water upside down it glugs to allow water out and then air in. As soon as the pressure builds up it swaps over to bringing air in instead of water out, and then swaps over again. If you were to put a hole in the bottle with which to draw air there wouldn't be a problem as the pressure would be maintained. In this instance the hole in the bottle is connected to the breather valve which is connected to the charcoal canister. Its also probably why if I pump fuel in very slowly it seems to be ok.

So I think the problem lies somewhere along that breather element; whether its a blocked pipe, a stuck valve, or the charcoal canister is full. I read somewhere else that if you fill your car right to the brim then it can sometimes expand in hot weather into the charcoal canister, causing the vapour to clump together. I regularly filled mine to the brim which has some merit, do/did you?
 
Beeacon said:
As far as I can make out its got to be something to do with the pressure in the tank building up (because the fumes aren't getting to/through the activated charcoal filter). That way every time you put a little fuel in, the air pressure builds up and shuts off the pump.

If you imagine turning a bottle of water upside down it glugs to allow water out and then air in. As soon as the pressure builds up it swaps over to bringing air in instead of water out, and then swaps over again. If you were to put a hole in the bottle with which to draw air there wouldn't be a problem as the pressure would be maintained. In this instance the hole in the bottle is connected to the breather valve which is connected to the charcoal canister. Its also probably why if I pump fuel in very slowly it seems to be ok.

So I think the problem lies somewhere along that breather element; whether its a blocked pipe, a stuck valve, or the charcoal canister is full. I read somewhere else that if you fill your car right to the brim then it can sometimes expand in hot weather into the charcoal canister, causing the vapour to clump together. I regularly filled mine to the brim which has some merit, do/did you?
Click to expand...

Yep always fill my car up to the brim, that's interesting about the breather, my cars going in for a service in June, might get them to have another look
 
I also just found this in their repair manual:

https://www.newtis.info/tisv2/a/en/e89-z4-sdrive35i-roa/repair-manuals/16-fuel-supply/1VncHKRTF8

I'm not entirely sure what it means or what the diagnosis is, but its obvious that they've had the problem before and logged it.
 
very interesting,,,, thanks for that,,


love this ,,,,
"Important information:

The fault patterns in the test module depend to some extent on the production period, optional equipment, motorisation and other features. It is therefore possible that not all content or different content to that described above may be displayed for different vehicles."
 
Beeacon said:
As far as I can make out its got to be something to do with the pressure in the tank building up (because the fumes aren't getting to/through the activated charcoal filter). That way every time you put a little fuel in, the air pressure builds up and shuts off the pump.

If you imagine turning a bottle of water upside down it glugs to allow water out and then air in. As soon as the pressure builds up it swaps over to bringing air in instead of water out, and then swaps over again. If you were to put a hole in the bottle with which to draw air there wouldn't be a problem as the pressure would be maintained. In this instance the hole in the bottle is connected to the breather valve which is connected to the charcoal canister. Its also probably why if I pump fuel in very slowly it seems to be ok.

So I think the problem lies somewhere along that breather element; whether its a blocked pipe, a stuck valve, or the charcoal canister is full. I read somewhere else that if you fill your car right to the brim then it can sometimes expand in hot weather into the charcoal canister, causing the vapour to clump together. I regularly filled mine to the brim which has some merit, do/did you?
Click to expand...

I’d be surprised if the issue is caused by pressure build up as you’re not forming an airtight seal with the fuel nozzle any potential pressure would just be vented to atmosphere :thumbsup:
Rob
 
Sorry to be posting constantly, but Pelican Parts have had this issue a lot on the E90 by the looks of it and have shown how to diagnose the issue mentioning that it can be the following things:

- Charcoal canister
- Vent to the charcoal canister
- Solenoid
- DMTL pump
- DMTL pump lines

The diagnosis is to pull the vent away from the charcoal canister, then try and fill the car. If the car fills without any clicking then its a blockage in the charcoal canister or beyond (which i think is the DMTL pump). If it continues clicking with these hoses unplugged, then its one of the hoses that is blocked or the solenoid and can be cleaned with some compressed air.

Link to fuel supply 3D image:
https://www.newtis.info/tisv2/a/en/e89-z4-sdrive35i-roa/repair-manuals/16-fuel-supply/8HvwldCJ

Link to E90 advice:
https://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E90/FUEL-Charcoal_Canister_Replacing/FUEL-Charcoal_Canister_Replacing.htm

I am by no means a mechanic but this may help point your mechanic in the right direction :)
 
Smartbear said:
I’d be surprised if the issue is caused by pressure build up as you’re not forming an airtight seal with the fuel nozzle any potential pressure would just be vented to atmosphere :thumbsup:
Rob
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Hi Smartbear,
Just from a bit of reading up that seems to be how the pump nozzle operates, as it starts to fill the tank the air that is inside the tank can't escape, so the fueling hose backs up and shuts off the pump. There must be at least a little bit of air able to escape the tank through the fueling hose as you can start to fill it again briefly before it cuts out once more, that and the breather hose probably isn't fully clogged up, but clogged enough to make fueling a pain.
 
Well it wouldn't be so bad if Z4s had 3 Series sized tanks! Another 8 litres would be useful.

Then again my E91 has the well-known issue with the vent that means if it is much over three-quarters full it stinks of petrol - sometimes you just can't win. :lol:
 
I carried out a trick I use with my wife's 2 series... put the nozzle in with the trigger at the top..fills both cars fine...
 
Mines a 2010 SDrive 30l Auto and it's always been a pain to fill up unless I put the pump nozzle in 180 degrees around the other way. Then it goes in full chat and doesn't switch off. I just assumed it was the configuration of the pipework that was causing it to back up.
 
I put the nozzle fully in and then let it find a natural position to sit. It seems to work for me. The nozzle seems to come back out about an inch.
 
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