Fuel not filling to max

[kujiwara]

Re: Fuel not filling to max

Just ran the tank to almost dry and put gas in until it came out.... Didn't mean to do it but that's one way to make sure it's totally full.
This is what I see on the gauge


Then a few hundred meters later


Then another km or so it dropped down to the first picture again..

I'm gonna try the fuel pump rotating thing

[Lars]

Re: Fuel not filling to max

Just got gas and got 52 litres in the tank and that wasn't forcing it in

[funkin]

Re: Fuel not filling to max

My pump only sits one way though, fwd and 4motion tank and pumps are different probably

No, they turn. You'll be surprised at how little you'll have to turn it to get it to change. I had the issue in my 20th and my 04.5 Gli after changing pumps.

[kujiwara]

Re: Fuel not filling to max

Good thinking - I’d rotate the pump first though.

My pump only sits one way though, fwd and 4motion tank and pumps are different probably

[All_Euro]

Re: Fuel not filling to max

Just a side note, I'm assuming you positioned the pump identical to the old one. If they aren't clocked right the float wouldn't have been or won't be in the proper position, giving you an inaccurate reading. Before spending too much time with vcds and running around trying to recalibrate it on a false reading, I'd fill the tank and try and rotate the pump, counter clockwise if I remember correctly, until you get to a full reading on your gauges. At that point I'd re-calibrate the gauge as doing so without having a full sweep on your level sensor float isn't going to help out a whole lot.

Good thinking - I’d rotate the pump first though.

[funkin]

Re: Fuel not filling to max

Just a side note, I'm assuming you positioned the pump identical to the old one. If they aren't clocked right the float wouldn't have been or won't be in the proper position, giving you an inaccurate reading. Before spending too much time with vcds and running around trying to recalibrate it on a false reading, I'd fill the tank and try and rotate the pump, counter clockwise if I remember correctly, until you get to a full reading on your gauges. At that point I'd re-calibrate the gauge as doing so without having a full sweep on your level sensor float isn't going to help out a whole lot.

[kujiwara]

Re: Fuel not filling to max

Have you pushed the vent button on the left side of your tank fill port? Thastll Hel you get a few more liters in by ventimg, but as for your guage....try Witchcrafts vag-com idea.

There's a button? Where is this magic button ahah

Filling the TDI I can get 54L if it's bone dry.

I'll text you and we'll figure a time for next week or weekend, I'm going to Whistler this weekend.

Sure! Whistler is so nice.

Late model GLI’s def have a 55L tank... and they’re completely plastic - thick plastic. I’ve put 53.xx L in my old tank more than once or twice. The tank I have now is supposed to be 62L but I regularly add 65L and it’s not reading as totally empty either. I’d try VCDS first and then think about valve or sending unit fixes.

yeah I'll do that, thanks for the tank info!

[All_Euro]

Re: Fuel not filling to max

My old 03 2.8 gli always take over 50L but I never saw this blue car go over 50L even when it had the 1.8T. When I did the engine swap I did find out the fuel pump and tank is different on this 04(didn't change it), maybe our late model GLi has a smaller tank? Does your gauge go to max when you fill up?

Late model GLI’s def have a 55L tank... and they’re completely plastic - thick plastic. I’ve put 53.xx L in my old tank more than once or twice. The tank I have now is supposed to be 62L but I regularly add 65L and it’s not reading as totally empty either. I’d try VCDS first and then think about valve or sending unit fixes.

[witchcraftz]

Re: Fuel not filling to max

Filling the TDI I can get 54L if it's bone dry.

I'll text you and we'll figure a time for next week or weekend, I'm going to Whistler this weekend.

[Geobmx4life]

Re: Fuel not filling to max

Have you pushed the vent button on the left side of your tank fill port? Thastll Hel you get a few more liters in by ventimg, but as for your guage....try Witchcrafts vag-com idea.

[MechEngg]

Re: Fuel not filling to max

Should have the same size tank. My gauge goes up to max and works just fine

Also my old 2003 wolfsburg never took over 50L either....

[kujiwara]

Re: Fuel not filling to max

How would dents or rocks in the tank cause a measurement issue? It doesn't measure the volume, it measures the liquid level (tangeable) and then calculates the % volume based on that. Any volume taken up by rocks on the bottom of the tank would not prevent the system from getting up to 100% full.

I'm thinking that your sender unit isn't calibrated correctly, even from stock i'm not sure that they come calibrated to work with your ECU. There is also ability for different revisions of sender units having slightly different range scales.

I've never been able to put over 50L in my tank, even when it was basically dry. It has always been 49.x liters. I definitely haven't been able to put a full 55L in it either, so your tank isn't honestly out that much.

My vehicle has had gas filling issues, i have to fill mine slowly or else it creates too much back pressure and shuts off the pump because the nozzle trips out. It has something to do with the purge valve or LDP it seems:
http://forums.vwvortex.com/showthrea...Fueling-Issues

My old 03 2.8 gli always take over 50L but I never saw this blue car go over 50L even when it had the 1.8T. When I did the engine swap I did find out the fuel pump and tank is different on this 04(didn't change it), maybe our late model GLi has a smaller tank? Does your gauge go to max when you fill up?

[MechEngg]

Re: Fuel not filling to max

How would dents or rocks in the tank cause a measurement issue? It doesn't measure the volume, it measures the liquid level (tangeable) and then calculates the % volume based on that. Any volume taken up by rocks on the bottom of the tank would not prevent the system from getting up to 100% full.

I'm thinking that your sender unit isn't calibrated correctly, even from stock i'm not sure that they come calibrated to work with your ECU. There is also ability for different revisions of sender units having slightly different range scales.

I've never been able to put over 50L in my tank, even when it was basically dry. It has always been 49.x liters. I definitely haven't been able to put a full 55L in it either, so your tank isn't honestly out that much.

My vehicle has had gas filling issues, i have to fill mine slowly or else it creates too much back pressure and shuts off the pump because the nozzle trips out. It has something to do with the purge valve or LDP it seems:
http://forums.vwvortex.com/showthrea...Fueling-Issues

[kujiwara]

Re: Fuel not filling to max

I agree that it sounds like a capacity issue, not a measuring/reading issue. Is your tank dented? Any chance a previous owner put rocks or something in it that is taking up volume?

Hmm i never thought of that, I'm sure there's no rocks that will take 5L of space in my tank but I'll check for dents.
I'm thinking it could be some sort of ventilation issue when filling up? I read up about it and saw the words "purge valve" and "carbon canister", will these two things affect this issue?

[Jester B]

Re: Fuel not filling to max

I agree that it sounds like a capacity issue, not a measuring/reading issue. Is your tank dented? Any chance a previous owner put rocks or something in it that is taking up volume?