12 replies to this topic

[jimmyH]

I am struggling to remove the earth strap on my MPI. Trying to get to the bottom of a lack of charge getting to the battery (it is leaving the alternator at about 14v) But i cant get to the bolt on the bulkhead side without removing master cylinder and all sorts. And need the car by monday (uni), dont want to casue more than i can fix.
Can i do a conductivity test, will that be accurate enough. If not, any removing tips ??
It looks a little corroded but not massively so, has gone slightly green, terminals are little rusty but not excessively so.
Help

Thanks

[Southy]

Have you tested the battery?Try a meter reading on the battery with the car turned off, should be something like 12.4v, now try it when somebody starts the car for you, should jump upto around 14.3v and settle back down to around 12 again.

[jimmyH]

Have you tested the battery?Try a meter reading on the battery with the car turned off, should be something like 12.4v, now try it when somebody starts the car for you, should jump upto around 14.3v and settle back down to around 12 again.

I know its not the battery, I switch between two, fully charged it lasts about 3 days and then will eventually die, i then change it for another. Im sure its something like the earth strap or the main cable. But how do i get to the cable ??

But thanks for the speedy reply

[tommy13]

As Southy has said, you should check the voltage at the battery with the engine running at about 1500 rpm. You should get a reading of around 14 volts or a little more, same as at the alternator. If it is lower than this, take a jump lead and attach one end to the alternator body and the other end to a good earth point on the body of the car. If the battery voltage jumps up to the 14v area then the earth strap is indeed at fault.
If it is very inaccessible it is acceptable and often easier to attach another strap ( cheap and available at motor factors)in a different location.

[jimmyH]

As Southy has said, you should check the voltage at the battery with the engine running at about 1500 rpm. You should get a reading of around 14 volts or a little more, same as at the alternator. If it is lower than this, take a jump lead and attach one end to the alternator body and the other end to a good earth point on the body of the car. If the battery voltage jumps up to the 14v area then the earth strap is indeed at fault.
If it is very inaccessible it is acceptable and often easier to attach another strap ( cheap and available at motor factors)in a different location.

Have done this, the voltage reads at the low 13's. With a jump lead it jumps up nicely. From the alternator to the bulkhead side of the earth strap looses about 1 v so sure thats at fault. Anywhere apart from mini spares i could find one suitable for a mini ?

[dmdangermouse]

ye its tricky to get to the nut. In the end i put the car on stands and used a long extension bar and got it from underneath.
Once its off give it a scrape with a wire brush.

[tommy13]

As Southy has said, you should check the voltage at the battery with the engine running at about 1500 rpm. You should get a reading of around 14 volts or a little more, same as at the alternator. If it is lower than this, take a jump lead and attach one end to the alternator body and the other end to a good earth point on the body of the car. If the battery voltage jumps up to the 14v area then the earth strap is indeed at fault.
If it is very inaccessible it is acceptable and often easier to attach another strap ( cheap and available at motor factors)in a different location.

Have done this, the voltage reads at the low 13's. With a jump lead it jumps up nicely. From the alternator to the bulkhead side of the earth strap looses about 1 v so sure thats at fault. Anywhere apart from mini spares i could find one suitable for a mini ?

Virtually any good motor factors, accessory shop or Halfords will sell these in a variety of lengths usually with a 8mm eye terminal on each end. As suggested above, have one more try at removing and cleaning the original strap.

[jimmyH]

I will give it a good clean, have ahd a good go at some other terminals like the alternator and solenoid. But will concentrate on earth strap tomrrow.
Thanks guys

[Ethel]

There's no rule that says you can only have one earth strap - add one somewhere else. Though, if you had a one volt drop across the strap, I think it would really struggle when carrying the current of a spinning starter motor.

[jimmyH]

There's no rule that says you can only have one earth strap - add one somewhere else. Though, if you had a one volt drop across the strap, I think it would really struggle when carrying the current of a spinning starter motor.

I think i will add another one, as suggested on the minispares website. Just need to find one. Looks like im going to have to wait another week as at uni at the moment.

[burnleyadam]

I had the same issue a few months ago, fitting another earth cured the problem. TOUCH WOOD!

[Ethel]

You can get an earth strap from anywhere - doesn't need to be Mini specific.

[jimmyH]

I will look tomrrow, have a family garage who are willing to fit it really cheap, as i need a ramp. Will hunt one down tomorrow if i can find somewhere open.
Thanks guys .