Firstfives.org

So, I have heard that if you have a small amount of gas in the tank....half gallon, the car will not run very well. Car runs better over 1/4 tank...is this true? In other words, these cars need to have plenty of fuel in the tank to run good.

I have a set of h/r springs and bilstein shocks that fit a 85 m535i, will any of this suspension fit my 1980 m535i?
thanks for any help,
jm

realoem.com has exploded view parts lists, rockauto.com and autopartswarehouse.com has product photos of the in tank fuel pump.

You'll see the in tank pump mostly has a very fine screen (paddle, foot deal) at the bottom, and the sliding float for showing the fuel level on the gauge. After thirty few years it's not shocking to find crud is messing up the filter screen and float from accurately reading the fuel level.

We know there is a red light on the fuel gauge to tell us when the needle leaning way to the left isn't fooling around. If the fuel needle is jumping around or seems to stick, drop, that's usually about the connections to the gauge needing cleaning, properly set up.

Otherwise, I've found putting gas in costs the same before I run out, as after.

As for suspension parts, generally no. But there's a list of common parts in the Technical FAQ's. ( See E12 resources, upper left column.)

The gauge is reading full, but I drained the tank, due to a hole in the tank. I sorta-plugged the hole, and put 1/2 gallon of gas in the tank. I know it is not full. The car was acting as if it was running out of gas, but maybe I just got some air in the line....or dirt.
thanks again,
jm

Yes, particularly if the intank pump is bad, you need at least a gallon or a gallon and a half. And if you haven't replaced the intank pump, it is bad. The low fuel light comes on at about 14.2 gallons and you can run it til about the 15 mark before it starts getting iffy, but the rated capacity is 16.4.

Thanks guys. I will put in some more gas and see what happens. Suppose to get the tank repaired/replaced this week.
jm

I am still waiting on the people that are suppose to fix the tank, but I sort-of have the leak fixed, and changed the lines and put some more gas in.
Car starts great and runs really good.
jm