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325ixE30
06-11-2009, 01:51 PM
I just bought my 2nd E30, a 91 318is in April and it does something my 90 325ix did all the time.

The fuel gauge moves about all the time. If you tap on it the needle will go to where it should be.

Is this a common problem for E30's?

The next question is obvious, is there an easy fix?

I'm sure its a loose or corroded wiring problem, or sending unit..... but I'm no expert.....

BigD
06-11-2009, 02:01 PM
Yeah this is pretty typical when a ground connection is loose somewhere (not exclusive to the fuel gauge). The gauges ground against the board on the back, through a threaded post. When the nuts that hold it in work themselves loose in time, the gauge goes funky. Pull the cluster and tighten them (or find a new one if you've lost one).

325ixE30
06-11-2009, 02:34 PM
Is pulling the cluster an easy DIY? (I don't want to mess anything up)

BigD
06-11-2009, 02:46 PM
Is pulling the cluster an easy DIY? (I don't want to mess anything up)

Unless you have an airbag, yeah it's easy. I've never tried pulling the cluster with the wheel in place but maybe it's possible. Without an airbag:
-pop out your horn button
-undo the big nut that holds the wheel on (center the wheel first, and reinstall it centered, so you don't end up with a wonky steering wheel)
-remove the thumb nuts behind the lower edge of the cluster to remove the trim piece above the steering column
-this will expose the screws on the bottom edge of the cluster
-some of the screws hold down a plastic trim piece that goes all around the cluster, remove this
-after removing the trim piece, you'll see the screws on the bottom edge of the cluster which hold it in, and two screws at the top of the hood holding
-the top two screws hold down two long tabs, pull these down gently (they're recessed into the dash) and roll the cluster forward
-undo the wiring connectors on the back: pull the black holddowns out until they click, the connectors will then come out easy
-they're color coded so don't worry about the big ones, but if you have any extra wires like for the cruise control, take a picture to remember where it connects
-you'll now have the cluster out, remove the screws that hold the rear cover on, remove the cover, and then it'll be pretty clear where there should be nuts holding the gauge down
-reinstall = reverse of removal

325ixE30
06-11-2009, 02:48 PM
Cool! Thanks.

I'll try this on the weekend. Any special tools or just a Phillips?

BigD
06-11-2009, 02:52 PM
Yeah, everything's phillips. Have a good small, sharp one for the small trim screws, don't strip these.

If you have the lower steering column cover you may need to remove this too, to get to the upper trim piece thumb nuts. Just feel around for these - shove your hand under there, move it up to around where the upper trim piece is, and feel for a nut about 1cm thick, ribbed. Just like the kind modern computers have on the back for removing the access cover. There's one on either side of the steering column.

FuryriderX
06-11-2009, 11:21 PM
the real way to fix this is to actually take the cluster apart and re-flow the solder pad on the board where it grounds, and clean up the surfaces with emery cloth.

but you might not need to go that far - if the nut is loose or missing, installing/tightening will do the trick.

cocacola bob
06-12-2009, 12:41 AM
just took my cluster out this week put back in after work project added trim rings to the gauges found an excellent site for viewing step by step pictures to remove the cluster by googling diy e30 (do it yourself) then reading directions on the how to remove cluster but good pictures on the how to replace dashboard shows you everything. it's a little nerve racking don't want to break 20 year old plastic but if you're patient and don't force anything nothing will break good luck.

Mister
06-12-2009, 09:39 AM
you don't need to remove steering wheel at all,i can pull my cluster or your cluster in under 5 mins.pull the lower trim piece,remove cluster screws and cluster surround,when its all loose,see the dog ears up top,pull them down AND ROTATE THE CLUSTER towards you,so the dog ears are heading to the floor,remove the wiring harnesses,small flat screw driver (for the locks)remove the speed sensors from the speedo,remove the light plugs x2,better to pull the wires than the sockets,usually pretty ackward.now that its free,wiggle it out TOWARDS PASSENGER SIDE AND DOWN ABIT TOWARDS GEARSHIFT,you will sneak right out tickety boo.As for fixing your problem,the solder pads are ****ed,tightening might help but its temp at best,the trace is cracked barely hanging on,and the design of the mounts for both fuel and temp guages barely have surface contact as it is.I've added solder to the pads with temp success but doesn't last,swapped boards,had it apart 50 times.Last attempt was i cut out tin foil for the Pad and built it up to put pressure on it.its working in cold weather but dances on a warm day. this next attempt i am going to hard wire new wires to the guage,if you follow the traces back to the junction both pin outs are present,some fine wire a notch or two,and i think it will work.mister