help me solve my fuel gauge problem!

[Dj Buttchug]

I have a 90 325i chassis with an m42 drivetrain in it.

The chassis has this fuel tank


This is the 318i fuel tank


Notice the 318i tank does not have a second fuel level sender. The 325i larger fuel tank does.

My fuel gauge jumps around from 1/4 to 3/4 constantly and I can never get a accurate reading. Yes ive made sure the connections are tight on the back of the cluster. Is it possible that i need a 325i fuel gauge??? The cluster was swapped from the 318i into the 325i chassis. Real oem shows two different part numbers for them. One that is 60L and the other that is %60L. not sure what that means...
The fuel gauge worked perfectly in the 318i chassis. But now it does not.

So my question is this. Is it possible to by pass the secondary sender and use just one like the 318i tank does?

Heres what Ive tried
1: unplug the sender on the drivers side. result is the fuel gauge reads empty. no signal.

2. Unplug the sender on the passengers side that drops into the fuel pump housing. result: same thing. fuel gauge pegs empty.

Im lost. The only thing that does work is the reserve light on the gauge. If im almost out of fuel it will still illuminate red.

help me out.....

[Dj Buttchug]

:(

[wodcutr]

The fuel gauge itself is not getting the right ohms if it is for a two sensor car and you are only giving it one sensor to work with.

[Dj Buttchug]

I see what you are saying. two sensor tank is sending the correct signal but the gauge is for a one sensor car. need to change fuel gauges then?

[wodcutr]

Yes, put your old gauge into the 318 cluster and all should work good again!

[Dj Buttchug]

well, shit. i sold the old cluster haha.

will try this and report back. thanks

[mcskibadee1]

I have a fuel gauge if you want it. $5 shipped. I was chasing around a fuel gauge issue and it was my sender. If your fuel gauge is jumping around it might be the sender behind the driver. Mine did the same thing and everything was correct, I pulled the sender and tested it and the ohms were all over the place.

First step though is to definitely get the right gauge.

[Dj Buttchug]

pm sent^