Full Tank in 5 Gallons

[bernzpeed]

I just replaced my engine with 63k miles on it and my car chassis is about 176k miles.

My gauge says empty so I just filled my car with gas and the gas pump nozzle stops after 5 gallons. My gauge shows half a tank of gas.

What could be wrong? Fuel sender?

[StereoInstaller1]

What year is your car?

[E30Gus]

is this an e to i swap by any chance? Did you swap clusters?

[bernzpeed]

it's an 89 325i, engine came from an 87 325i. yes i swapped clusters. i used the cluster and si board from the 87 325i to match the engine mileage. the 89 cluster was not working at all.

[bmwstephen]

bernz, can you verify if the issue came up as the result of the swap or prior to the swap? cause it likely sounds that the
fuel sender on passenger side out. I had a similar issue only it showed 12 gallons to fill up instead. turns out the sender unit on my driver side that reads the remaining 4.6 gallons was dead.

[lennon]

the early cluster won't read right with the late tank. early tank/cluster uses one level sender, late tank/cluster uses two. try disconnecting the 2nd sender (not the fuel pump side), and jumping the two pins of the connector together.

or maybe better yet, get a working late style cluster (with late fuel gauge) and swap in the speedometer with the mileage you want.

[bernzpeed]

@stephen,

i bought the car non running before the swap. so who knows..

@lennon, what should i expect to happen when i jump the 2 pins?

[lennon]

if you're using the early fuel gauge, you can expect jumping the 2nd sender connection pins to make your gauge read correct. i can't remember if the 1st sender (where pump is) is different from early to late. i don't think it is, but if so you may need to swap to that.

OR, like i said, it seems simpler/ more proper to just get a working late model gas gauge...

[E30Gus]

Whoa before jumping pins and shit, swap the fuel guage from the early model into the cluster of the late model. This should take care of it unless the old fuel guage is crap too.

[bmwstephen]

bernz keep us posted on the results

[bernzpeed]

Whoa before jumping pins and shit, swap the fuel guage from the early model into the cluster of the late model. This should take care of it unless the old fuel guage is crap too.

I sold the old cluster.

[lennon]

ha... if the fuel level gauges were the same there wouldn't be this thread. you cannot just use the old style with late style tank/sensors. there are two sensors in the late tank, one in the early. the gauges are different.

getting a late model gauge is the simplest solution.

edit: not sure what e30gus was trying to say, but this post was in response to his suggestion.

[bernzpeed]

Okay, just an update. Today i drove the car even though the gauge has fallen way past the E. Then finally, I decided that I would pump gas. 8 gallons later, it's a full tank. I start driving and the gauge is now in full tank. I have not change the cluster yet.

Still under observation. Since I work from home, I hardly drive so, we will see if the gauge stays working.

[bmwstephen]

Now is a good time to unplug the passenger side fuel level sender and see if your gauge behaves anymore abnormal than it is already

[bernzpeed]

I finally replaced the fuel gauge for a late model. Looks like it's back to being almost accurate. Whew!