Cannot fill up gas tank

[jlevie]

Originally Posted by jeffnhiscars

I'm quite sure that the pump does not move fuel from one side of the tank to the other on any e30

55L tanks have a cross-over tube between the tank sections and returning fuel dropped into the right side of the tank. 63L tanks don't have a cross-over tube. Returning fuel goes to the lower left side of the tank and into a siphon that lifts fuel over the drive shaft hump.

[603Racing]

^^^ Of course this assumes the odometer is accurate.

Comparing my odometer to my GPS and Google Maps it tracks about 16% less distance than it should. Odly enough, the speedo reads about 10% high. The speedo is likely due to my 205/50 tires. The odo... who knows, it's probably has a cracked gear that may also be missing teeth.

[jeffnhiscars]

Originally Posted by 603Racing

^^^ Of course this assumes the odometer is accurate.

Comparing my odometer to my GPS and Google Maps it tracks about 16% less distance than it should. Odly enough, the speedo reads about 10% high. The speedo is likely due to my 205/50 tires. The odo... who knows, it's probably has a cracked gear that may also be missing teeth.

If your 205/50s are 16's they are very close to OE.

So your odometer is broken, fuel gauge is questionable, tires are swapped, speedo is out & the tank may or may not fill properly...and you are wondering about your fuel consumption.

I'm missing something here.

[TobyB]

I'm quite sure that the pump does not move fuel from one side of the tank to the other on any e30

Ha. Guess what? It does. On everything after 9/87 the return line from the rail acts as a
suction pump to draw fuel out of the driver's side sump and over to to the pump on the
passenger's side. It's not technically a siphon, but it's often referred to as such.
On the E36, it comes out with the sender so you can see it- it's a pretty neat design.

It's how they get fuel over the saddle on later cars.

If that's not working, it'd leave 3-4 gallons on the driver's side.

But if it was me, I'd carry 5 gallons in the trunk, run the thing until it stopped, add the 5
to get to the gas station, and then see how much it REALLY takes.

If it THEN isn't taking 16, then it might be time to look at the suction system.
But like others, I'd mistrust the gauge before it. It's pretty simple and reliable.

Oh. Unless your fuel pump's almost dead. Then it might not be flowing enough
to draw the fuel out of the driver's side. But you'd probably have driviability problems
before that happened...

t

[603Racing]

Originally Posted by jeffnhiscars

If your 205/50s are 16's they are very close to OE.

So your odometer is broken, fuel gauge is questionable, tires are swapped, speedo is out & the tank may or may not fill properly...and you are wondering about your fuel consumption.

I'm missing something here.

I'm not the one wondering about consumption, I was just supporting the comment on gauges being unrealiable when it comes to calculating fuel consumption. And my wheels are 15" FWIW.

[jeffnhiscars]

I'm cross threaded.

<seguays to spectator mode>

[Classiks]

Originally Posted by TobyB

Ha. Guess what? It does. On everything after 9/87 the return line from the rail acts as a
suction pump to draw fuel out of the driver's side sump and over to to the pump on the
passenger's side. It's not technically a siphon, but it's often referred to as such.
On the E36, it comes out with the sender so you can see it- it's a pretty neat design.

It's how they get fuel over the saddle on later cars.

If that's not working, it'd leave 3-4 gallons on the driver's side.

But if it was me, I'd carry 5 gallons in the trunk, run the thing until it stopped, add the 5
to get to the gas station, and then see how much it REALLY takes.

If it THEN isn't taking 16, then it might be time to look at the suction system.
But like others, I'd mistrust the gauge before it. It's pretty simple and reliable.

Oh. Unless your fuel pump's almost dead. Then it might not be flowing enough
to draw the fuel out of the driver's side. But you'd probably have driviability problems
before that happened...

t

Toby that is really quite interesting because with my dented tank on the drivers side perhaps that siphoning actually isn't working and is leaving the 4 or so gallons which translates to 15 litres. Basically what I've been missing.

I'm also going to try what you suggested by running the tank completely empty with a jerry can in the back to get me to the pump and see exactly how much I can fill up.

Thanks again everyone