7 replies to this topic

[Bean]

Hi, all.

Just wondering if anyone can help us out with a problem that we have...?


My Mini just won't start!

The Mini went up to Stanford Hall and on the way there, just cut out on a hill! We found it to be a the main fuse (30A). We managed to sort that out and dragged it to the show. About half a mile outside the gate, the Mini just cut out again & wouldn't start back up. After a few choice words, and a lucky turn of the ignition, it started up again, with no problems!

Once we got into the show, it cut out again and wouldn't re-start at all.

We narrowed the problem down to the main relay box. So, we bought a new unit & also a new fuse. We then started him up and he started first time!!

We left him running for a bit, just to check that all was OK. It seemed to be fine!

Then, as we just pulled out of the gates, the engine cut out again & it had blown the main fuse again... We swapped that again and it then blew the relay box again!!


We've not had a chance to look at the Mini until today, but we've taken the relay box apart to see what's going on.

From tracing wiring diagrams etc, it would seem like it's the Main Relay that has blown on both boxes... We have tested the voltage in various places around the car, before and after fuses etc. We have checked the relevant fuses (A4, C8 etc) and everything's in tact. We have voltage at the main relay between White & White-Pink (11.75v).

The car will turn over, but will not fire. The fuel pump does not prime. The only relay that seems to respond is the starter relay. Given that the oxygen sensor relay and the fuel pump relay work after the main relay, we've put it down to that being the problem... also, as the fuel pump relay works when you manually close the points.

But, what we're wondering is, if it is the main relay what would cause this to happen and where can we look next?


The car is a 1986, but with an MPi conversion. The ECU, Alarm etc are all from a working car and are all matched.


Huge thanks in advance.

A Mini-less Bean

[miniboy1971]

I had a similar problem once where the main fuse blew and the engine cut out. Replaced the fuse, the engine fired up but it would cut out as soon as I shut the bonnet.

Turned out that a wire was shorting out against the underside of the bonnet, the offending item is between the expansion tank and wiper motor. I've ringed it on yellow on this photo - not very clear but hope it gives you an idea on where to look.

It even left a little burn mark on the rib underneath the bonnet.

I repaired the wire and put a bit of plastic conduit over the top (as seen in the photo) to give it a bit more protection.



Hope this helps....

[miniboy1971]

oops duplicated post.

Edited by miniboy1971, 18 October 2009 - 05:24 PM.

[Bean]

That's a very tidy engine bay!!

Any ideas what the wire went to, at all?

I'm pretty sure that the wiring is all OK, as we've only just put the MPi loom in. We checked it all over beforehand and repaired any bit that were suspect...?

Thanks for your help, Miniboy.

[miniboy1971]

Hi Bean...cheers for that. The photo was taken a couple of years ago and it's still much the same thanks to lots of cotton buds !!

I've had a quick look in the engine bay one end is connected to a black widget between the wiper motor and expansion tank. The other end disappears behind the air filter. The wire had worn through where it enters the connector on the top of the widget.

I've had a look in the manual and the widget is the 'evaporative emission valve'. One of the pipes coming out of this runs behind the rocker cover and the other goes through the inner wing to, I think, the cannister (filled with charcoal ?). All part of the emissions controls presumably.

When the fuse went, it was as if the immobiliser was activiated i.e. all the lights, radio, etc. worked, but it just wouldn't fire up.

Hope this helps...

Edited by miniboy1971, 18 October 2009 - 07:54 PM.

[Bean]

Hmm, it sounds similar to what's happening here. Everything works electrically, really - radio etc. It'll turn over, but because of the main relay, it's not priming the fuel pump and therefore not starting!

I will take a look around that area for anything that might be shorting, when I get back from work! - Thanks Miniboy!


(I think it'll take a lot more than cotton buds to get my engine bay looking that shiney, lol )

[mykweb]

It takes something big to blow a 30A fuse, esp teh one sin teh engine bay.

I had the same thing happen to me I was going around a round about and suddenly the car died. Radio still worked thou. LOL

What had happened is the loom that runs down behind the air filter, the Loom had been rubbing off the back of the airbox and then chaffed a wire and shorted out.

The MPi is pritty bad for the engine rocking back and forth. People usually add extra gearbox steadys or top engine steadys to solve this.

Mike

[greg.harvey]

When this happens, does the starter motor still crank? We're finding everything works fine but the engine won't *fire* (it will turn over though).