10 replies to this topic

[OlivierW2]

Hello,

 

I have a '99 Mini MPI.

I haven't been using it since last September, so during this time, the battery was removed and taken at home to regularly charge it. The battery is about 1yo and has been barely used (due to the worldwide sanitary situation and bad weather).

 

Yesterday, I put the battery back in my Mini. I've let the headlight switched on for a few minutes to let the battery warm up a bit, even if the weather is not cold at all.

Then I have disabled the immobilizer, heard the fuel pump activating and when I wanted to crank the engine, everything immediatly stopped: no more power (no headlight, no interior light, just nothing).

I haven't even heard the starter motor turning. There was no strange noise, no "magic smoke".

 

The battery voltage is still at 12,71V.

When I check the voltage in the engine fuse box, it's at around 6V... Any ideas what could have gone wrong? What can I check?

 

Well, for the moment I have disconnected the battery, just to be safe.

 

Thanks in advance for your help,

Olivier

[sonscar]

Corrosion at any terminal from the battery to the fuse box would be my guess,the large starter current oxidised it somewhere and it is now too bad to properly conduct.I would clean both battery terminals,battery earth,engine earths and starter solenoid connection first.Good hunting and be careful,the battery is very powerful even if it appears flat.,Steve..

[MacGyver]

Same here 5years ago.
Short circuit along the cable under the car on one of the clips holding the cable in place. Have a close look as it took ne a while to find it.
Mine was on the bend near the rear subframe just before it goes for the long straight under the floor.

Ben

[Steve220]

I had similar, turned out to be the battery earth point in the boot.

[viz139]

If the only thing disturbed is the battery it is most likely the the battery terminals or boot earth. I did work on a MPi with similar problem that turned out to be heavy corrosion on the main fuse box in front of the engine. 

[bpirie1000]

Had the starter wires corrode and earth off the body.

Also check the earth strap on the side of the top engine steady.

Maybe an idea to put a jump leat on the engine and the other side on the exhaust. Acti g as an additional earth...

Good luck..

[OlivierW2]

Hello,

 

Thanks a lot to all of you for your answers!

 

I didn't have much time, so I have only quickly checked and:

• Under the chassis, everything looks clean. The positive wire is the one going near the center of the chassis, but a bit on the right side of the car, right? It looks in good condition. I'll try to check it more carefully on Sunday or next week.
• It seems the earth lead from the battery to the body doesn't make a contact with the body... With a multimeter, I couldn't find the continuity between this lead and random area in the engine bay (engine, some screws, ECU case,...).

So, in the next few days, I'll unscrew this lead and clean its contacts.

How can I make a great contact with the body and this lead? I mean, without removing too much paint and getting corrosion.

 

Actually, this short lead should make contact to the body with a bolt (and nut?) in the boot. Can I also connect a second wire to somewhere else? Maybe to the top of the right rear shocks? If it makes sense...

 

 

@sonscar: yes, I'll pay attention to the battery: I know it's a good idea to not wear jewels or watch or others metallic wristbands

 

@MacGyver: Ok, I'll try my best to check this cable. Especially near the bends.

 

@Steve220: yes, it really looks like it is my problem. Well, I hope it's only that, so shouldn't be too difficult to fix.

 

@viz139: the main fuse box looked alright. But I'll reopen it and will remove the fuses to check more and clean what I can. It probably can't hurt

 

@bpirie1000: last year, the engine was removed and put back by a professionnal. I'll look if the earth strap is well connected. What do you mean with "other side on the exhaust", is it at the manifold? Or somewhere else?

 

Olivier

[OlivierW2]

Hello,

 

I have great news :-D

I have just tested the continuity between the rear right shock nut and various area in the engine bay (like previously: engine, ECU case,...) and they is a connection

 

So, for now, I have added a cable from the negative connection to the battery and to the shock screw. Measuring in the fuse box of the engine bay, I found around 12V (the other day it was around 6V).

Every lights are now working and I have been able to start the engine without any problems at all! :-D

 

So, thanks again for all your help

 

My fix is just temporary, because I don't have the hardware handy to make it permanently. I'll fix it in the next few days or weeks.

My permanent fix will be: fixing the earth connection with the regular bolt (like it normally should be), adding a cable to the shock absorber and another to the two others bolt in the rear of the boot (I guess those are to attach the subframe to the body).

I still need to check and clean the fuse box.

 

I am still interested to know how I can make a good earth connection with the regular used bolt in the boot. I haven't loosen the bolt too much: I don't have that much space to work in my garage and don't know if I could loose a nut under the car.

 

Olivier

[viz139]

The shock absorber is rubber mounted!! shouldn't work

[bpirie1000]

The nut is usually retained with a little strap under the boot floor. I personally would remove the bolt. Wire brush it. Maybe even tap the bolt to make sure threads are allmgood and be happy with that.. afterall they have survived since 1959 with that type of mount..

[OlivierW2]

Hello,

 

Thanks to both of you!

 

@viz139: oh, you're right. But it fixed my problem, maybe the shock's screw barely make contact with the body, so my solution works for now but only temporary: with vibrations I could have problems.

Well, I'll fix it next week, when I'll finalyy be able to drive my Mini

 

@bpirie1000: Yes, I'll remove the bolt and wire brush it.

Being in France, my tools are metric ones. Of course I have imperial spanners and sockets to work on my Mini, but not more advanced tools like tapping tools. I'll check if I can find a cheap imperial kit, or maybe replace the complete bolt.

 

Olivier