50 replies to this topic

[greg.harvey]

Hi all,

1999 1275 MPi Mini won't start. It was absolutely fine yesterday, drove about 30 miles. Parked up, stopped, went to start it this morning, the starter motor cranks but it won't fire. Being an MPi I just stopped trying - if it doesn't fire, it's not going to fire! Of course, normally she goes after 3 or 4 cranks. And if I forget the immobiliser then it won't crank at all, so it's not that.

So I figure it *must* be either a fuse or a wire. Trouble is, the car is newly purchased - I've ordered a Haynes manual from Amazon, but it's not arrived yet. Can anyone point me in the right direction as to what to check/clean/jiggle??


Cheers,


Greg

[greg.harvey]

One thing possibly worthy of note - did top up the oil yesterday (but didn't overfill it) - just thought I'd mention that in case it could be related, but I don't see how, unless something has caused oil to get somewhere it shouldn't? Any known problems around that?

[gronkjor]

Might be the fuel pump fuse. Can't see how the oil could affect it.

[greg.harvey]

Thanks, just checked that, it's fine sadly. Checked all the main fuses as well while I was at it, and they're fine. So fuse is out.
Also thought to check the fuel cut-off switch, but wasn't that either.

Hmm. Crank sensor is something that's come up a few times in other threads. Anyone know where that's located?
Edit: scratch that - seems the crank sensor would make it run badly, but it would probably still start?


Greg

Edited by greg.harvey, 03 August 2011 - 11:17 AM.

[greg.harvey]

PS - I have a multimeter from my electronics student days, but no idea where to point it at when working on a car - so if some kind soul can give me some step-by-step guidance for checking sensors/coil/etc. then I'm up for doing a bit of that! I just wouldn't know where to start...

[greg.harvey]

It Lives!!!

In a last defiant act, I reset the keyfob with the alarm system a few times then turned the alarm on and off a few times. When I was content I'd seen enough orange lights flashing and was sure it was disarmed, I tried again - and it started! Not very scientific, but there you go. I don't know if the alarm/immobiliser thing was related or coincidental. Certainly a suspicious coincidence!

Anyone had anything like that before with the factory immobiliser? It's very strange, because it shouldn't even crank the engine if it's still immobilised...

[greg.harvey]

And it's dead again... fine for two days, today it does exactly the same thing...

Is it possible to disable the immobiliser/alarm system? I guess not, but worth asking.


EDIT: Actually, the more I think about it, the more I think it likely the alarm system thing was a red herring. There's clearly some intermittent fault, and being intermittent it's surely electrical. I'm just thinking this through again, if the immobiliser were playing up truly then the starter motor shouldn't crank at all. (Unless the immobiliser is *really* knackered and is doing something it shouldn't do at all!)

So, what are the things that could cause a Mini to run fine normally one day, then suddenly refuse to fire, then run fine again a few hours later? It must be a finite list of possibilities...

EDIT 2: Mind you, a friend of mine pointed out it could still be an immobiliser fault, if the immobiliser is only half-disarming, allowing the starter circuit but not the ignition circuit.

Edited by greg.harvey, 05 August 2011 - 09:48 AM.

[greg.harvey]

Mostly talking to myself here, but as an IT guy I know it's always good to carry on a thread until resolution so other people can find answers in the future.

So with that in mind, I'll continue my monologue.

Mini did it again this morning! I rolled it out the driveway and parked it on the street, as I always do when it doesn't start and I need to get at the Volvo. Except this time, on a hunch, I tried to start it from there. After cranking for 20 seconds it fired. I have a suspicion the angle of parking makes a difference. It's parked pointing uphill in the drive, won't start, roll it out the drive so it's pointing slightly DOWN hill, it starts!

Fuel pump on its last legs, maybe?

Edit: To test this theory, parked it pointing downhill on the drive tonight to see how it fares in the morning.

Edited by greg.harvey, 06 August 2011 - 07:18 PM.

[jamesmpi]

Did she start up this morning?

[danie garry]

i dont think your theory of the pump being gone can be right, the pump draws petrol from the tank through the top not like the carb tanks that take from the bottom

on my spi i had trouble with the immobiliser fob, lucky the spare 1 worked!

[greg.harvey]

No start again this morning.

But it rained last night, which left a tell-tale streak of petrol in the run-off water. It's definitely leaking petrol. Probably a tiny leak in a line somewhere, not enough to affect the running of the car, but if it stands for more than a few hours then all the fuel in the lines drips out and it takes an age for new fuel to draw through. I'm now 99% sure this is the problem. Job now is to find the leak!

Where does the line run and are there any likely points?

[liam_italian]

I suspect its a problem with the immobiliser, have you tried changing the battery in the fob first and then pressing the deactivate alarm button on the fob 8 times?

Edited by liam_italian, 08 August 2011 - 10:01 AM.

[greg.harvey]

You reckon? I started down that route, but the behaviour feels more like fuel starvation and the trickle of petrol in the rain water kinda points me that way. Still, won't hurt to disconnect the battery for half an hour, reconnect and reset the fobs, to see if that makes a difference...

Is there really any history of low battery in fob causing immobiliser to *half* disarm though? Seems really odd that it would allow the starter to crank but not let the engine fire. I would think it would be all or nothing?

[liam_italian]

It's either a problem with the immobiliser or a faulty cut off switch, as when the cut off swich under the bonnet is pressed it will still allow the engine to crank over, it just wont start.

I doubt very much its a fuel starvation issue otherwise you'd be having problems when your driving and putting your foot down!

[greg.harvey]

OK, so you don't buy the idea that it's a very slight leak - the reason I'm flogging this is the problem only happens after the car has stood for some hours. It *never* plays up straight after running, or even an hour or two after running - just when it's stood a while (e.g. over night) which is strange.

Just to try the cut-off switch, I don't know how the internals of that work. Is it simply a case of it pops and breaks the flow? In which case, if I get someone to hold down the cut-off switch while I crank, do you think that would help, if the cut-off switch is dodgy? (I thought of that and did press it, but it didn't seem to help. But then if it's not working right, maybe it needs someone to hold it - just a thought.)