- Joined
- Apr 27, 2012
- Points
- 100
I bought a project Z3 around January time. I drove it from Cape Town back up to Johannesburg without a functioning fuel gauge... scary stuff with lots of fill up stops.
Since then, I have had the fuel pump / sender out no less than a dozen times. A previous owner had obviously had a go at sorting out the common Z3 / BMW fuel gauge issue - erratic or non functioning display on the cluster. In the process he had broken one of the small clips which holds the housing carrying the float arm and ceramic card sensor. When I first removed the unit, I found a cable tie holding it to the main body housing the actual fuel pump..
I bought a new replacement ceramic sender card, and using a broken unit for the part that holds the ceramic card and the float arm, I replaced the plastic clip on housing which holds those components.
Prior to buying a new ceramic card, I had had the pump out to replace the broken housing as described above, I refitted the unit but still had a zero reading on the cluster gauge. After several attempts at cleaning the original card with rubbing alcohol and using 2000 grit paper on the two little sprung contacts which ride across the ceramic card, I still had a flat liner... That's when I decided to replace the ceramic card.
When that arrived, I pulled the unit again, fitted the new card and..... still no cluster reading.
Pulled it again and found another assembly error from the previous owner. The two sprung contacts have a very specific way of being housed - he hadn't refitted them correctly. So, that sorted, I re-fitted the unit, but again nothing.
Today I pulled it for the last time. I had checked all the connectors, the wiring from tank to cluster and the ceramic card for correct operation and resistance reading on my multi-meter. Everything was working including the cluster gauge which I had taken in to a specialist repair shop for testing.
Finally I had a good look at the fully assembled unit, and I noticed on the inner side, there is a small round plastic button covering a little rubber diaphragm. I popped the little button off, removed the rubber bit and managed to easily thread a piece of cotton through the hole which emerges at the upper hose connection on the outside of the unit. I then tied the inner side end of the cotton to the float and popped the unit back into the tank.
I didn't replace the screw on nut thingy, but lined it up as per the mark at the bottom, and pulled on my piece of cotton which raised the float arm inside the tank.
The cotton managed about 20mm before the float arm got stuck inside the tank.
That was the beginning of 3 hours of trial and error bending the float arm one way then another and checking by putting the unit back into the tank each time to check if it would move freely.. finally I found the right combination and for the first time since I got the car I have a fully functioning fuel sender. Cluster gauge is working 100%. I checked by filling the tank in 4 stages.. 1/4 at a time and each fill reflected the correct reading on the cluster.
If anyone else is suffering you can PM me an email addy and I'll mail you a "how to" with a photograph of the required bend alteration to the float arm.
Since then, I have had the fuel pump / sender out no less than a dozen times. A previous owner had obviously had a go at sorting out the common Z3 / BMW fuel gauge issue - erratic or non functioning display on the cluster. In the process he had broken one of the small clips which holds the housing carrying the float arm and ceramic card sensor. When I first removed the unit, I found a cable tie holding it to the main body housing the actual fuel pump..
I bought a new replacement ceramic sender card, and using a broken unit for the part that holds the ceramic card and the float arm, I replaced the plastic clip on housing which holds those components.
Prior to buying a new ceramic card, I had had the pump out to replace the broken housing as described above, I refitted the unit but still had a zero reading on the cluster gauge. After several attempts at cleaning the original card with rubbing alcohol and using 2000 grit paper on the two little sprung contacts which ride across the ceramic card, I still had a flat liner... That's when I decided to replace the ceramic card.
When that arrived, I pulled the unit again, fitted the new card and..... still no cluster reading.
Pulled it again and found another assembly error from the previous owner. The two sprung contacts have a very specific way of being housed - he hadn't refitted them correctly. So, that sorted, I re-fitted the unit, but again nothing.
Today I pulled it for the last time. I had checked all the connectors, the wiring from tank to cluster and the ceramic card for correct operation and resistance reading on my multi-meter. Everything was working including the cluster gauge which I had taken in to a specialist repair shop for testing.
Finally I had a good look at the fully assembled unit, and I noticed on the inner side, there is a small round plastic button covering a little rubber diaphragm. I popped the little button off, removed the rubber bit and managed to easily thread a piece of cotton through the hole which emerges at the upper hose connection on the outside of the unit. I then tied the inner side end of the cotton to the float and popped the unit back into the tank.
I didn't replace the screw on nut thingy, but lined it up as per the mark at the bottom, and pulled on my piece of cotton which raised the float arm inside the tank.
The cotton managed about 20mm before the float arm got stuck inside the tank.
That was the beginning of 3 hours of trial and error bending the float arm one way then another and checking by putting the unit back into the tank each time to check if it would move freely.. finally I found the right combination and for the first time since I got the car I have a fully functioning fuel sender. Cluster gauge is working 100%. I checked by filling the tank in 4 stages.. 1/4 at a time and each fill reflected the correct reading on the cluster.
If anyone else is suffering you can PM me an email addy and I'll mail you a "how to" with a photograph of the required bend alteration to the float arm.
..... Thanks. I'm now looking for the source of a rattle at the back.. Been at that one for a few months without success..
