I decided to drive my classic to work today since the weather was so nice this morning. The car had been garaged for a month and I felt that it needed a good drive to charge the battery.
I drove 10 miles on the highway @ 65+ MPH and then pulled off onto a 35 MPH road when my troubles started.

The engine began to “hiccup” to the point where I had to feather the throttle and clutch to get the car over to the shoulder. As I was pulling over to the shoulder, the ignition tone sounded each time the engine revved. A few seconds after that, white, electrical smelling smoke began to billow from the dash.
I quickly grabbed the fire extinguisher from the back seat and opened the bonnet where I found additional smoke coming from the positive cable attached to the starter.

I didn’t see any fire, so I fanned the starter cable with a file folder until it cooled off. I then disconnected the battery and had the car towed back to my house. I didn’t have a chance to get a good look under the bonnet before I had to leave for work.

Here’s where the car stands:

1. Ignition switch – Key is stuck in ignition and switch won’t go to position 0 or position 3 (start) steering wheel is not locked.
2. Emergency lights and headlights still work. Radio and everything else is dead.

Anyone have any ideas on what could have happened before I tear the car apart this weekend? I’m guessing the wiring harness may be toast. Hopefully the ECU isn’t fried. I don’t know why the key is stuck in the ignition. BTW - It's a `94 SPI

Thank you.

 

Sounds to me like your ign switch melted - the plastic part on the back, not the mechanical part where the key goes in - and it may have done quite a bit of damage to your wiring harness - but I'd look there first......

 

So you let all the smoke out, eh? Seriously though, it could have been much worse. Sorry to hear about your problem.

If the switched 12v wire from the starter solenoid to the ignition switch became grounded and it wasn't fused, it would cause that. I guess a faulty alternator (fried regulator) may cause the same problem ... I read a post from classic Mini owner where the alternator started generating huge amounts of voltage - discovered by the dash gauge.

If you're lucky, the only things damaged are the wire to the ignition switch and the switch itself. Typically, the insulation on all of the wires in the loom will get melted due to the heat and the entire loom will have to be replaced.

My guess is that the reason why the headlights and emergency lights still work is because they use unswitched 12v power ... meaning they do not require the ignition switch to be in the 'on' position to function. I'll bet your dome light and brake lights still work as well. All of the engine electrics (coil, starter, electric gauges) will work on switched power, and rely on the ignition switch to provide the power.

Good luck, and let us know what you find out.
Jeff

 

Thank you for the replies. I took a quick look at the car this evening and it appears there's a fair amount of damage. Looks like I will have to replace the wiring harness, ignition switch and possibly the alternator.

Starter wiring damage:


Here's some melted wiring at the firewall. 15 AMP inline fuse wasn't blown:


Ignition switch damage:

 

Eureka! I traced the problem back to a faulty ignition barrel. The return mechanism failed and the key remained in the start position for several minutes. I don't know how, but the engine started and ran for a good while before the car began to buck like a bronco and smoke started to billow from the dash.

I untaped most of the wiring loom and found that the melted ignition wires did not damage any surrounding wiring. Hopefully I can get by with just replacing the ignition switch, ignition wiring and two fusible links that burned up. I don't know if the starter and solenoid are damaged. Is there an easy way to test these?

 

Easy to test, make sure transmission is in neutral, with a short 'jumper wire' (or screwdriver, etc.) connect the small post of the solenoid that connected to ignition switch to ground and the starter should turn the engine over, check that there is 12 Volts to the other small post, do not short that one to ground.

If the solenoid tests bad, use a large jumper cable to connect across the two large terminals of the solenoid and starter should work, you could also use the jumper from positive (negative ground system) battery post to the large starter cable, again there should be 12 Volts to the 'hot' terminal.

These tests will create a spark, make sure you smell no gas fumes before doing the tests.

 

I'll give that a shot today. Anyone know what size fues should be in the four-fuse fuseblock from top to bottom? I have a 35 AMP fuse in the first slot where the melted ignition wires are connected.

 

I was able to get the starter motor to turn by jumping the terminals on the solenoid. The only problem is that it spun freely without turning the engine over. I pulled the starter from the engine and the starter gear and flywheel appear to be ok.

 

If you do end up needing a harness let me know, I have a complete harness from a 93. The only removed from the harness is the heater core pigtail. Everything was labeled as it came out.

 

Thank you for the offer. I got away with changing out the white and brown ignition wires and some fusible links. I jury rigged an ignition switch from some scraps I found in the garage until the replacement arrives from the UK. I'm glad the door locks work. LOL

 

I had to chuckle at your "mod." Its just the sort of thing that 5 years later I'd be be asking myself why haven't I done anything about that?

 

Does that really work??

 

I was hell-bent and determined to get the car running again after I found out the ignition switch was the culprit. Especially since the car has been collecting dust in the garage for over a month.

It's actually quite amazing / scary how simple the Mini ignition circuit is. Remove two steering column screws, remove two bolts holding ignition switch and steering wheel lock to the column, connect ignition wire to battery wire, touch starter wire to battery wire and Voila! Gone in 154 seconds.

My TEMPORARY setup works great! I just extended and taped the wires under the floor mat to the right side of the seat so I wouldn't have to reach under the dash. The folks at MiniSport must really love me now.