9 replies to this topic

[unseen]

Been doing some work on the mini today, mainly planned on fitting the new interior I picked up and the new securon seat belts i bought... But as happens when we're all working on something, you notice something you know is not right but can never work out WHY!

The picture below shows 2 cables coming from the boot earthing point.. The main obvious one is the battery negative.. But the other one was a mystery to me till today..

 DSC00328.JPG   723.71K   23 downloads

It runs through the back seat.. down the length of the floor and then into the engine bay where it is attached to another earthing point.. So 2 questions really... Anyone know WHY someone would do that??? And secondly do you think removing it would create a problem?

Thanks

Rob

[Big_Adam]

Anyone know WHY someone would do that???

Previous owner had a ground fault, added 2nd cable, solved ground fault.

[Doooeks]

Anyone know WHY someone would do that??? And secondly do you think removing it would create a problem?

This wire is needed if your mini has a fiberglass shell. If you have a steel shell then you can disconnect it if all your earth points are nice and clean... you'd be best to disconnect one end of it and use a meter to check that the front earth point and the engine are both connected to the battery Negative before you remove it.

Mike.

[Silicon Skum]

Don't ask me why, but I have a feeling you need to check if there is an engine block to bulkhead earth strap fitted (in case you don't know, its fitted to the block just above the clutch housing / left hand side of the engine as you look at it from the front, and it's connected to the bolt on the bulkhead where the top engine steady is fitted).

Check to make sure it's there and is in good shape, I have a feeling that this may have been by-passed with the cable to the boot for some reason. I could be wrong. You will need this earth strap if you decide to remove that extra cable.

SS

[Matrix]

Looks like audio earthing to me maybe it had a big sound system before?

[unseen]

Anyone know WHY someone would do that??? And secondly do you think removing it would create a problem?

This wire is needed if your mini has a fiberglass shell. If you have a steel shell then you can disconnect it if all your earth points are nice and clean... you'd be best to disconnect one end of it and use a meter to check that the front earth point and the engine are both connected to the battery Negative before you remove it.

Mike.

afaik it's all steel (well.... as much steel as a 92 mini should have I'll act stupid for a sec.. What am I looking for on the meter?...

Don't ask me why, but I have a feeling you need to check if there is an engine block to bulkhead earth strap fitted (in case you don't know, its fitted to the block just above the clutch housing / left hand side of the engine as you look at it from the front, and it's connected to the bolt on the bulkhead where the top engine steady is fitted).

Check to make sure it's there and is in good shape, I have a feeling that this may have been by-passed with the cable to the boot for some reason. I could be wrong. You will need this earth strap if you decide to remove that extra cable.

SS

Ahhhh... Good thinking! I'll have a good looksee and see what shape it's in..

Looks like audio earthing to me maybe it had a big sound system before?

A friend who looked at it as well thought that.. There is plenty of evidence that someone liked there music (8 speakers when i first got it! now down to 6....) but i wonder how much of some of the wiring (there's more max power/bangin audio cabling) was done by just using what he had lieing around

[unseen]

I've had another look.. This time checking the main engine earthstrap.. (Annoying how you ignore the blindingly obvious and see the other things!)

 DSC00330.JPG   816.17K   4 downloads
As you can see in that pic.. The other end of the "extra" earth strap.... And the blue one goes...
 DSC00332.JPG   667.46K   3 downloads
And then this is where I guess we go back to the standard wiring going finally to here..
 DSC00333.JPG   739.14K   2 downloads

I'll be getting a new meter tomorrow so help is appreciated...

Rob

[Doooeks]

afaik it's all steel (well.... as much steel as a 92 mini should have I'll act stupid for a sec.. What am I looking for on the meter?...

You're looking for 0 Ohms Resistance... but that never happens so probably up to about 5 ohms is OK doesn't need to be exact, if you've got an earth problem, you'll be measuring way more than that (kOhms & MOhms so it's easy to see)

Before you start, Hold the leads together and Zero the meter (if Possible) or just remember what it reads and take this as 0.

[unseen]

afaik it's all steel (well.... as much steel as a 92 mini should have I'll act stupid for a sec.. What am I looking for on the meter?...

You're looking for 0 Ohms Resistance... but that never happens so probably up to about 5 ohms is OK doesn't need to be exact, if you've got an earth problem, you'll be measuring way more than that (kOhms & MOhms so it's easy to see)

Before you start, Hold the leads together and Zero the meter (if Possible) or just remember what it reads and take this as 0.

Thanks for that.. I shall grab a new meter from Maplins tomorrow and let you know what results I get...

(on a side note.. what do you think of This meter just for mini maintenence)

[Silicon Skum]

I've had another look.. This time checking the main engine earthstrap.. (Annoying how you ignore the blindingly obvious and see the other things!)

 DSC00330.JPG   816.17K   4 downloads
As you can see in that pic.. The other end of the "extra" earth strap.... And the blue one goes...
 DSC00332.JPG   667.46K   3 downloads
And then this is where I guess we go back to the standard wiring going finally to here..
 DSC00333.JPG   739.14K   2 downloads

I'll be getting a new meter tomorrow so help is appreciated...

Rob

Ahhhh!!, an interesting point was made about that being audio install grade cabling (actually I thought it was too, but didn't think anything of it). What I *sussect* has been done, is that some VERY high power amps were installed, and I'm betting he was having problems with voltage drop-outs / line noise etc. The body shell of a mini is not realy ideal for carrying heavy loads for amps (it's fine for starter motors, but amplifiers are MUCH more picky), so he's wired in a direct negative feed from the front, to the back of the car to boost / clean up the power feed to the amp(s), plus he was probably having trouble with other electrical devices (lights etc) on the car when the amps were sucking up the power.

From what I can see, the extra cable should not cause any extra problems (may even solve a few you didn't know about yet...), and could be left in place without any worries. If however, you wish to remove it, just check the condition of the engine earth strap (upgrade / replace etc.) and remove the extra cables, OR use the existing blue cable as the earth strap, and mount it to the bulkhead (lower resistance than the wings, wings have more spot welds, so poorer connection) or to the bulkhead side engine steady bolt (original place for earth strap fitment). Then check with the multi meter to make sure of the best connection you can get. Job done.

SS