Earth Problems?

[eel330]

Hello all.
Have been having a few problems for a while but it all seems to have come to a head.

The fuel gauge has been occasionally reading full when not, so I assumed it was an earth problem. I cleaned the front 2 earthing points but this did not cure the problem. This has been going on for over a year and no further problems so I lived with it.

At the weekend the oil gauge was jumping around a bit. Today somebody as work came in and said my car was locking and unlocking itself. It has done this before and when I went to check it seemed ok. When I went to drive home there was not enough power to turn it over. Once I got it started 1 of the indicators was permanently glowing. Got it home and cleaned up the front 2 earths as best I could but has not cured the problem. Undone the passenger side earth on the tunnel and the car suddenly started locking and unlocking itself very rapidly until it ran the battery down again. I tightened the earth bolt up again but this did not stop the problem. I have now disconnected the battery and given up for the night. I'm pretty sure it's an earthing problem . Don't know whether I've cleaned the points thoroughly enough or whether there is something I'm missing? Any answers are gratefully received.

Dan

[spend]

eel330 said:

Undone the passenger side earth on the tunnel and the car suddenly started locking and unlocking itself very rapidly until it ran the battery down again. I tightened the earth bolt up again but this did not stop the problem.

I thought that was the side the battery connected to? (you do mean mean the bolt under the trim & carpet thats a twqt to get to).

Dave

[chrispitman]

There are quite a few earthing points I have found, here goes

Front chasis end by rad.
Engine earth driver wheel arch on outrigger support.
center console battery side Behind carpet just below dash
Center console driver side behined carpet just below dash
Boot on end of chasis rail, note there are 4 bolts on the rear a couple on filler side on mine had wires connected.

Thinks thats about all I have found so far.

[eel330]

Thanks for the replies. Yes, I meant the one under the centre trim. I wasn't aware of the earthing point at the rear. I need to check and clean the 2 internal points and locate the one at the rear. Whats the best method of cleaning them?

[captiv8ed]

With regards to your fuel guage, I would agree that sounds like an earth problem, or perhaps a loose connection at the sender. However, the central locking snag which is draining your battery I would think other wise. That sounds like an intermittent short to me. If it was simply a bad earth, then the central locking wouldn't work. Remember, all earths are linked via the chassis if they're good. If you have an UNWANTED earth, then that is a short and of course the electrickery can find its way into other linked systems (via all GOOD earths). Perhaps you could look around the fuse panel for something shorting the systems together, then move on to remove suspect relays until the problem has gone.

Hope this helps,

Nick

[spend]

I suspect when you accessed the earth point under the console - this was like flashing the battery on/off rapidly. Not very good for you electrical equipment - disconnect the battery first I do like the battery disconnect switch - just for these reasons. Alarm/immobs seem particularly sensitive to how 'nicely' you reconnect the battery.

Dave

[eel330]

I've just realised I occasionally had the problem of turning on the ignition and nothing happened. Turn the key back and then on again and the ignition came on. Does this give anymore clues or am I spending a weekend in the footwell?

Dan

[spend]

See my point about bad connection of the main battery to chassis grounding.

Dave

[taylormj4]

captiv8ed said:

....That sounds like an intermittent short to me. If it was simply a bad earth, then the central locking wouldn't work. Remember, all earths are linked via the chassis if they're good. If you have an UNWANTED earth, then that is a short and of course the electrickery can find its way into other linked systems (via all GOOD earths).....
Nick

Hmmm, once the current is into the chassis, assuming the battery earth connection is good, the current won't come back out of the chassis up a different earth connection. It will only return to the battery - the lowest point of potential. You are getting confused with equipment connected to a common earth, where these problems can occur. The current cannot get to earth at the earth point, so flows back up a negative wire connected to the same earth, and to earth via a different piece of equipment.

Matthew

[CaptiV8ed]

taylormj4 said:

You are getting confused with equipment connected to a common earth, where these problems can occur. The current cannot get to earth at the earth point, so flows back up a negative wire connected to the same earth, and to earth via a different piece of equipment.

Matthew

Yes, I have (pardon the pun) got my wires crossed there. I'm taking into fact that the whole car electrical circuit is on big earth return system. You are indeed right that if all other elements are working correctly, then the return will go direct to battery. But I have seen problems where a short has affected other parts of the car's electical system.

[eel330]

Right have cleaned and reconnected the 2 front earths and the 2 transmission tunnel ones. Unlocked and locked the car a couple of times and all seemed ok. Tried it 1 last time and the left indicator stayed on again. Disconnected the battery and had a look at the fuse board. Reconnected the battery and tried locking again. All works ok after a few tries but hsvrn't tested fully as it was getting dark. Nothing happened the first time I turned on the ignition but turned off and on again and seemed ok. Also cleaned and tested the courtesy light swicthes whihc were ok but that does not work either. I did have it working a long time ago but it hasn't worked for a while. I'm thinking there is 1 more earth i need to find which is the central locking one, I have to look under the dash for a problem or I run a new earth from the battery to chassis? Anyone got more ideas?

Thanks

Dan

[spend]

eel330 said:

...I have to look under the dash for a problem or I run a new earth from the battery to chassis? Anyone got more ideas?

I think some early cars had some dash earths connected to the steering column ~ clamp under/behind the cowl IIRC. Sorry I pretty much carved mine up & cant (dont want to) remember what it was like

The earth strap across the engine mounts is another PITA (mot connected to your probs - but while you're at it...)

Dave

[eel330]

Latest update.....Spent the last couple of nights finding the earths and cleaning them up. Go the one on the front of the chassis, drivers side wheel arch, and both on the centre console. Also found one under the steering wheel cowling (thanks for that Spend) . Fitted it all back in, then pulled out fuse board and checked and re fitted all the fuses. Took the car out and all the gauges held steady and locked and unlocked the car a few times. Went out for a drive, pulled up in the garage and locked the car.......the left indicators stayed on again so I had to disconnect the battery. I have ordered a new courtesy light door switch as one of them didn't always work, but don't so how this can be the problem? Any ideas? Thanks for the help so far.

[spend]

Bl00dy alarm/immobs I guess. Nobody wants to discuss online so I would advise a call to Carl Baker and see what he says TBH.

Must rush just dropped a bomb over the other side, want to check if I got any bites

Dave

Edited by spend on Thursday 3rd May 23:42

[mgaut]

I had a problem with the indicators staying on, only on one side.

Following advice on here it turned out to be an alarm problem; Carl Baker is your man.

Mike

[eel330]

Thanks for all the replies. Cleaning the earths seems to have sorted the problem with the gauges. Spoke to Carl and he seemed to think it was the alarm. Can't afford to sort it out at the moment but I have another immobilizer on it so am just using the keys to lock it, and not using the central locking which seems to be the main problem. Might have the dash top off to see if I can cut the wires to the indicators so I can use the central locking again.

Thanks again

Dan