Fuel Guage Needle Flickering

[dickster]

Hello, before anyone asks yes I have used the search function but nothing gave me a conclusive answer to my problem.

I recently changed the complete instrument binnacle on my '88 Sport (made by Motometer) as the rev counter wasn't working and the service indicator lights were on. I used a VDO unit from a chrome-bumpered Sport but when plugged in with the coding plug used from the later car the fuel guage didn't work.

I swapped the old original later fuel guage into the earlier binnacle and although everything works the fuel gauge flickers and twitches-not a major issue but slightly irritating and looks like it belongs on something made by British Leyland. I also noticed that when I switch the engine off the rev guage flickers once.

Having looked at the BMW parts computer I noticed that the earlier and later fuel guages are different-although I have read on the zone that they should be interchangable I'm wondering if I need to use an early type fuel guage or the later type as the tank and sender are the later type? Is the earlier fuel tank 55L and the later 60L??

Also I noted that the later Motormeter binnacle had the larger circuit board batteries whereas the earlier binnacle has the smaller batteries-I though this was supposed vice-versa with the later dials using the smaller batteries?

cheers for any help

[Brianmoooore]

Flickering fuel gauge is usually a loose securing nut for the gauge on the back of the cluster (did you tighten it?), but I suppose that it could be a poor connection on one of the gauge's pins, since it's been recently unplugged.
A worn level sender in the tank can also make the needle flicker, but this would normally only happen with certain amounts of fuel in the tank.
The little jump made by the tacho needle seems to be a characteristic of the SI board with lithium batteries.
The fuel gauge needs to be matched to the tank size, but this isn't an early/late thing. Generally speaking the 'lesser' E30s have the small tank, and the more desirable ones have the large tank.
The SI boards with the larger NiCd batteries were the first to be introduced, but all of these will have been replaced at least once by now. Even after the introduction of the SI board with the smaller lithium batteries, BMW repaired and recycled the NiCd type, so any particular cluster could be fitted with either.

[dickster]

Thanks Brian, I checked the two nuts but they're tight, and I've checked and re-checked the contacts where the fuel guage sits.

There are about five different guages according to the parts computer-the tech-1 sport that the cluster came out of was fairly basic in spec-it didn't have an OBC, both the fuel guages were working correctly in their respective cars before either were touched it was only when I connected up the earlier binnacle to the later car that I noted that the fuel guage wasn't working.

Basically I'm not sure if I should be buying a replacement guage to suit the older car/binnacle or a newer guage to suit the tank/sender of the later car.

[adam_b]

My fuel gauge has stopped working since i changed the loom in my car, there is a feed from the fuel sender under the back seat, but from there to the dash there is something up? any ideas as to why this is happening? i've checked the dash, replaced the clocks, changed the fuel guage also and still no joy