'80 528i Fuel Sender float wires

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brotherhay
Posts: 59
Joined: Fri Apr 17, 2009 11:40 am

'80 528i Fuel Sender float wires

Post by brotherhay » Thu Aug 16, 2018 4:47 pm

As many before me have discovered, the fuel gauges in these cars tend to get a little jumpy over time.

I cleaned up the posts of the fuel gauge itself, and also pulled the sender out to check that.

After playing with the sender, it was obvious the fault was with the sender unit. There are two wires that run the length of the sender for the float to tell the gauge where the fuel level is.

Does anyone know of a source for those wires? They are certainly thin, not shielded at all. No idea of gauge, maybe 30 gauge? Just looking for a source to get some of this. Looks easy enough to replace. Solder it to the bottom copper pad, and then pull it tight and solder it to the top connector.

If anyone knows of a source, or even just the type of wire, and size, that would be very helpful

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Mike W.
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Re: '80 528i Fuel Sender float wires

Post by Mike W. » Fri Aug 17, 2018 4:11 pm

No source I've heard of. I suspect the sending unit is still available since they used it thru the E28 run, but that would be a pretty special wire with a moderate resistance. A contact cleaner might be of help, but doubtful. Double check every ground, they're critical for the fuel and temp gauges.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter

brotherhay
Posts: 59
Joined: Fri Apr 17, 2009 11:40 am

Re: '80 528i Fuel Sender float wires

Post by brotherhay » Thu Aug 23, 2018 5:55 pm

I was unsure as to what size the wires were, so Initially I bought a 40 gauge Nichrome wire. When it arrived, it looked too thin, but after taking out the sender and looking, they looked very similar.

I checked ohms on the wires that were in place, 41 ohms from end to end. Measured the same length 40 gauge Nichrome, and it ohmed out at 41 ohms.

40 gauge is whats in there, so I replaced the existing wires with new ones. Pulled em tight, soldered in place.

Just gonna watch that gauge, see how it goes.

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528i-1981
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Re: '80 528i Fuel Sender float wires

Post by 528i-1981 » Fri Aug 24, 2018 11:58 am

I'd say you nailed it.

Can you confirm that you used 80/20 nichrome? The resistivity varies by alloy, but 80/20 is the most common. Also, did you use stranded or drawn?

I coaxed new life back in my sender with a thorough cleaning, but remember being shocked at how expensive they are new. With this info I'll have some 40-gauge nichrome in my stores. Thanks!
(oo=00=oo) Eric
1981 528i Manual

brotherhay
Posts: 59
Joined: Fri Apr 17, 2009 11:40 am

Re: '80 528i Fuel Sender float wires

Post by brotherhay » Sun Aug 26, 2018 9:08 am

this was listed as a Nichrome 80 wire, I assume that means 80/20

40 Gauge AWG Nichrome 80 Resistance Wire 100’ Length

And yea, Im with you. Theres not much along the lines to fix in a sender unit, but at $300 or whatever it is they are asking for a new one, well try to fix it up yourself first, sheesh.

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Mike W.
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Location: Sonoma County

Re: '80 528i Fuel Sender float wires

Post by Mike W. » Sun Aug 26, 2018 12:27 pm

Nice fix, my hat's off to you. Where did you find the nichrome wire?
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter

brotherhay
Posts: 59
Joined: Fri Apr 17, 2009 11:40 am

Re: '80 528i Fuel Sender float wires

Post by brotherhay » Wed Aug 29, 2018 8:44 pm

Found it on Amazon

I actually purchased a sampler of Nichrome in various gauges. I think the total was less than $20 shipped

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