1G gas tank not filling all the way

[xander123]

so I have a 1990 talon tsi, and ive done some research but can’t find anything like this. people say our tanks hold 60liters(16gallons). I always fill up at around 1/4 tank, because the old owner said at 1/8 it’s most likely empty and the gas gauge is slightly off. but ive filled up at just above 1/8 before, and the most the cars ever taken is like 25.5 liters and I can’t find anything on why it’s taking less than half what it should

 

[AWD-Tony]

Next time you fill up, pull the pump and take a look at how much is in there. Should be close to the top. If that’s the case, the sender isn’t reading properly.

 

[xander123]

Next time you fill up, pull the pump and take a look at how much is in there. Should be close to the top. If that’s the case, the sender isn’t reading properly.

if you mean see if theres gas all the way up, yes there is, i always see gas there but it still takes so little to click off. I’m still new, you mean a sensor or something that tells the fuel gauge what to read? if so does that mean my tank is probably half full when I fill up at 1/4

 

[AWD-Tony]

Where are you seeing gas?

This is how you test the fuel sending unit (the mechanism that measures how much gas you have).

Possibly. If the gauge isn’t reading correctly, you could be at half a tank when you’re filling up. You want to verify that the tank is full after you have filled up.

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Does your gauge read full after you fill up? And how many miles are you getting until it reads 1/4 or 1/8 tank?

 

[xander123]

Where are you seeing gas?

This is how you test the fuel sending unit (the mechanism that measures how much gas you have).

Possibly. If the gauge isn’t reading correctly, you could be at half a tank when you’re filling up. You want to verify that the tank is full after you have filled up.

You must be logged in to view this image or video.

Does your gauge read full after you fill up? And how many miles are you getting until it reads 1/4 or 1/8 tank?

when I fill the tank it gets close to full, but never actually full. maybe at most 1/8 from being full I’d say, and I’m not too sure how many km/miles I’m getting. but theres been times where I have to gas up 2 times in one day

 

[AWD-Tony]

when I fill the tank it gets close to full, but never actually full. maybe at most 1/8 from being full I’d say, and I’m not too sure how many km/miles I’m getting. but theres been times where I have to gas up 2 times in one day

Sounds like you have one of the following issues.
-Inaccurate gas gauge
-Gas consumption
-Issue filling up

How do you know it’s never full? Are you going off the gauge? I had the same issue with my gauge when I got the car. Sending unit wasn’t making good contact when float is at full position.

Next time you fill up, reset the trip meter. Then, next time you fill up, write down how many gallons it takes and note the mileage. Divide the mileage by number of gallons. This will give you mpg/kilometers per liter.

To verify it’s actually full next fill up, I would remove the fuel pump and look inside. If the gasket is original, you will need to replace it because it WILL leak.

 

[xander123]

Sounds like you have one of the following issues.
-Inaccurate gas gauge
-Gas consumption
-Issue filling up

How do you know it’s never full? Are you going off the gauge? I had the same issue with my gauge when I got the car. Sending unit wasn’t making good contact when float is at full position.

Next time you fill up, reset the trip meter. Then, next time you fill up, write down how many gallons it takes and note the mileage. Divide the mileage by number of gallons. This will give you mpg/kilometers per liter.

To verify it’s actually full next fill up, I would remove the fuel pump and look inside. If the gasket is original, you will need to replace it because it WILL leak.

the gauge never reads as full but when I fill up ill see abit of gas at the surface, like where I put the gas nozzle in. and I tried to fill up yesterday at about 1/4 but it only took about 10$ of gas before clicking off. the car read at 1/2 tank after that. could something be clogged? my gas consumption used to be pretty bad but I replaced my spark wires and it seems to have improved. afr reads at 13.6 driving, 10.2 wot and 14.7-15 idle

 

[AWD-Tony]

So we know for sure the gas gauge is inaccurate. I would fix this first. Without it reading correctly and you not physically verifying it’s full, we would all be guessing. The gas pump uses Venturi effect to shut the pump off so I’d guess that it is actually full.

To fix the sending unit, all you need to do is remove the pump, take off the sending unit and use a multimeter to check resistance while you move the float. Most likely the contact on the coil needs to be bent

 

[motomattx]

Hold on here, so your complaining that your car doesn't take as much money to fill up as other cars do with gas over $4.00 a gallon???

 

[xander123]

Hold on here, so your complaining that your car doesn't take as much money to fill up as other cars do with gas over $4.00 a gallon???

well here I’m paying 2$ a litre (mod edit: $7.57/gal), not sure what that is for gallons. but I dont like knowing something is not working proper in case one day it reads full and leaves me stranded

So we know for sure the gas gauge is inaccurate. I would fix this first. Without it reading correctly and you not physically verifying it’s full, we would all be guessing. The gas pump uses Venturi effect to shut the pump off so I’d guess that it is actually full.

To fix the sending unit, all you need to do is remove the pump, take off the sending unit and use a multimeter to check resistance while you move the float. Most likely the contact on the coil needs to be bent

would fixing the sending unit make the gas gauge accurate?