At wits end

[midijab]

I have been having issues with my fuel gauge. Already removed and checked the fuel sender unit. All seems well, variable resistance, etc. The problem is it reads full all the time. Luckily the red lamp in the front comes on when I'm close to being out of gas. Today I went for a nice leisurely drive and lo and behold, the fuel gauge started jumping around then settled on about 1/2 tank. Then on the next bump dropped to empty. Kept going to about half tank off and on, then go dead off and on. Now, before I finally got home the gauge went to full again like it did and now is reading full again!. Now the weirdest thing is, I now have rear brake lights on whenever the car is on. Anyone can help give me a clue on where to start looking. is there a short where both relays harness runs together? Thanks. BTW it's a 1971 2000 touring

[c.d.iesel]

sorry , I don't respond to gauge

questions - way to much information and history

to deal with. Wait till the pack returns to their

WORK computers in the morning.

O well - remove the cluster and clean all

electrical contact points, all grounds, all

fuses, all plug connections, look under

the trunk boards at the sending unit

wire / connections just for starters....

Corrosion, oxidation, broken wires,

loose connections, poor ground

connections are bad.

[Guest]

I have a bunch of spare ones if you want to try. I test one the other day and I know she is good. Email me if you want. No cost is involved so it might be worth it. MeyerE30@dc.rr.com

[BillWilliams]

you remove the wires from the sending unit (with the key in the on position?

What happens when you ground the signal wire and the ground wire?

[dubois]

most likely, all you have to do is install an additional ground wire to your cluster. If I remember correctly there are two places on the back, then you make a Y connection and find a nice ground on the chassis. Arm yourself with a voltmeter and a jump wire, you can see when the gage starts reading right.

BTW when I bought my car I thought the PO (previous owner) was kind enough to had left me a full tank of gas. I ran out of gas before I got home!

PS: I found this link that explains it better: http://www.02restoration.com/how-to-fix-an-erratic-temperature-gauge-in-1973-bmw-2002.htm

[midijab]

O well - remove the cluster and clean all

electrical contact points, all grounds, all

fuses, all plug connections, look under

the trunk boards at the sending unit

wire / connections just for starters....

I was going to get into the cluster as a last resort. I checked all the grounds and re-did a ton of frayed spade lugs, solder tinned, ground lugs and such. Now I have all turn signals, fog lamps, running lamp (in headlight), rear trunk lamp, low beams, high beams, cluster lamps, rear license plate lamp, inside fog lamp indicator lamp, rear running lamps, & reverse lamps working. I double checked and even removed the fuel sender, but to no avail.

I have a bunch of spare ones if you want to try. I test one the other day and I know she is good. Email me if you want. No cost is involved so it might be worth it. MeyerE30@dc.rr.com

Thanks for the offer, I'll pay shipping to and from, but let me try cleaning the cluster first. It may take a few days as I'm using this car as a daily driver. Incidently, when it jumped to around half tank, I looked inside with the sender removen and it was just about half full with gas! So my sender might be OK. I'll let you know. Thanks again.

you remove the wires from the sending unit (with the key in the on position?

What happens when you ground the signal wire and the ground wire?

I'll try that tomorrow. Is it normal to have 3 wires on the sending unit? I have ground, and two others. The two that's not ground only can go on one way otherwise the gauge is dead when they are swapped.

most likely, all you have to do is install an additional ground wire to your cluster. If I remember correctly there are two places on the back, then you make a Y connection and find a nice ground on the chassis. Arm yourself with a voltmeter and a jump wire, you can see when the gage starts reading right.

BTW when I bought my car I thought the PO (previous owner) was kind enough to had left me a full tank of gas. I ran out of gas before I got home!

PS: I found this link that explains it better: http://www.02restoration.com/how-to-fix-an-erratic-temperature-gauge-in-1973-bmw-2002.htm

Thanks! I'll read up and try to get schooled up before I tackle this again tomorrow! Since I'm digging into the cluster, I'll add another ground wire. Yes, I too ran out of gas, not knowing the hand brake lamp was also used as a low fuel lamp! I was puzzled when I first got the car thinking my hand brake needed adjustment because the big red lamp came on out of the blue!

A BIG THANK YOU to everyone on your suggestions! I'm having a lot of fun with this car as I cruised the beach today! I've attached a pic of the baby.

JB

[Guest]

I should be clear. I have the gauge not the senders.

[Guest Anonymous]

I have been where you are on more than one occasion.

First, despite what everyone else tells you about the poor grounds at the instruments, I have had the float in the tank stick and give the goofiest of readings.

Having checked out the sending unit, I would then agree to look at the instrument grounds. Unfortunately, after spending more time soldering ground wires to the instruments then it would have taken to re-ring the engine, I still had the problem. I later found myself swapping printed circuit boards to correct the problem. The point being that the fault may possibly lie with the 30+ year old circuitry. Naturally, this does not rule out the gauge itself being faulty.

On a related topic, you mentioned the "red warning light" for low fuel.

First, I always wondered what models were equipped with this feature.

Secondly, what triggers this light? Is it a separate sensor in the tank or does it work off the same signal from the float assembly? I can't help but wonder whether it isn't dependent upon much, if not all of the same circuitry as your fuel gauge- but without the gauge. Then again, I have never seen one actually work. I have had US models from 72 through 76 and none of them had this feature or none of them had this feature actually working.

If you determine the actual cause of your jumpin jimminey gauge, please post a follow-up.

[midijab]

I'll definitely post the fix once I determine the root cause. Anyway, I've seen the sender unit in a 1973 '02 and it has 2 spade terminals. One terminal is clearly ground and the other is safe to assume the signal. However, in my 1971 touring, there are 3 spade lugs. One again is clearly ground and the other 2 have wires hooked to them. One wire (brown/yellow) when removed, renders the gauge inoperable. Right now, with it plugged in, the fuel gauge pegs to full. The other wire is sitting there hooked up. When I remove it, I cannot determine if it will cause the big red cluster lamp not to light as I had already filled the tank. I can verify this once I run the tank down. Now internally in the sender unit, these are hooked to different terminations because when I swap the two wires around, the fuel gauge goes dead. I think I may need to do more research on this also.

Here's the working rear fogs:

[02Les]

Not an answer to your problem i'm afraid, although it does sound like you need a dedicated earth on the cluster.

I keep a Register of Touring Owner's and I do not believe I have yours.

If you wouldn't mind emailing me your VIN & location i'll add you and email you back the current Register spreadsheet.

lescartwright@juno.com

I realise this sounds like a scam, but I'm honest as the day is long (just ask me and i'll tell you!).

Rgds.

[BillWilliams]

on the tourings? And how it is wired?

[02Les]

on the tourings? And how it is wired?

So i've studied the attached diagram and I think I have it now.

The fuel float/sender (61) has 3 wires (1 being ground). One wire is wired via the handbrake switch (68) and the manual choke knob/switch (56) to the 12 pole cluster plug onto #5 pin. If you check the Cluster (top left hand on the diagram) #5 pin is wired (within the cluster) to the red tell-tale lamp.

Euro cars only had these 3 alarms. The brake fluid alarm level was not standard in Europe. It may have been an option, but the wiring diagram for a Euro does not show a brake fluid level alarm.

Edit: parts are shown top right (not left). It's because i'm in China!

[InkaSteve]

on the tourings? And how it is wired?

I only have the low Brake fluid level, choke, handbrake light functions on my 74. No low fuel light. Unless I just haven't run it down that low yet.

I do know that those gas tank floats can be pretty sticky in the sending units. Sometimes I think they get leaky and refuse to float anymore.

Will be interested in the solution.

Give Les your info...He is trustworthy, I have only been spammed 1000 times since I gave him mine. J/K..

Seriously, it is a good database. Where are you located??

[midijab]

Yep, I saw that low fuel light connection to the multiple signal cluster last night when going over the wiring diagram in the Haynes manual with a magnifying glass.

Les, I sent you an email.

Even though I'm having a lot of fun with this car, being essentially an '02 newbie, I have no real clue or reference point as to how this car is supposed to run/feel/ride. Is there any '02 specific mechanics/experts here in Southern California - South Bay area who could evaluate what's good/bad mechanically with this particular vehicle. It's running more than good enough right now so where I could probably wait till 8/4/2007 and take it to SLO.

[Craig74tii]

I may be totally off on this reply because I'm to lazy to read all the posts, but here goes.

On my tii I have a jumping gauge. Everyone says to run a Y ground, but to me that's a Band Aid and not really finding the problem. If it needed a Y ground, the factory would have done it.

In my car I noticed if I flicked the gauge cluster, the needle would jump, which means I have a problem either with the gauge itself or the big round connector. I cleaned the very small male and female connector on the gauge, and that helped, but still had a little jumping. I looked at the wiring diagram and one of the wires (I think #12) is a ground. I have yet to clean that connection.

Just a thought.