Help won't start

[Velocemitch]

I just can't fathom this, the Morris doesn't seem to want to start today. I have tried everything I can think of, but no go.
I fairly sure it's electrical as I don't have a spark. No fuses have failed, the Battery was good, (It's flat now though ), When I held the plug against the head to see if it sparked I got a slight shock, not strong enough to be a full HT belt, but I did feel it.
I wondered if it might be a duff coil, so I tried another, but still no go. Are the coils different for negative/positive earth?, as I tried the one from the Alfa so if they differ it would be a red herring.

The only thing I can think I might have done is messed some of the wiring up as I was working behind the dash to try to fix the washers, (didn't manage that either, not by best day ). I did find find a strange toggle switch hidden under the dash on the far right hand side, which seemed to have no purpose, it had a wire fixed direct to earth, then another one heading through the bulkhead, but not attached to anything anymore, it looked like it could have come from one of the terminals on the starter solonoid, it made me wonder if this was some sort of low tech imobiliser and I have cut the ignition circuit by knocking it off.

Any ideas people???

[Gareth]

That sounds like a low-tech immobiliser. Try switching it in the other direction. Phyllis had one of those, and it seemed to be a fabulous idea, until it shorted and burned out, taking half the ignition wiring with it.

You might find that this works, although I'd expect it to be connected into the low-tension circuit, which was how Phyllis's was wired. Whip the gloveboxes out and check the connections at the back of the dash - it is possible that you may have distrubed something. If it was working this morning, and you've been working on her this afternoon, you've messed up, I'm afraid! It's infuriatingly easy to do...

[Velocemitch]

Wish it was that easy Gareth, I did switch it over but it didn't affect anything, the problem is the wire leading to it was hanging loose I have no idea where it came from. I can only imagine it was intended to short out the ignition when switched across, but if removed it wouldn't affect anything.

[iddy]

I've put a similar switch on our car, and it works a treat. Mines connected to the coil, but I know some use the fuel pump. But if this was used on yours it should have started with what petrol you had in the carb.
I'm afraid it's going to come down to detective work - if you still have the lead connected to the switch try and work out how far it could stretch and take it from there.

Idris.

[bmcecosse]

If one side was earthed - and the other side is now not connected to anything - then it won't be causing you any problems! First off - is the fuel pump ticking ? Is the red IGN light on ? Is there a voltage at the coil - check with a meter or just a wee 12v lamp. Coil needs to be round the right way - it works both ways but gives best voltage the right way. Otherwise - check points and dizzy cap (centre carbon peg and spring ok ?) and rotor arm - and when was the capacitor last changed ? When they are old they don't build so much voltage.

[Velocemitch]

Unfortunately the Battery is flat and on charge now, so further checking is impossible for now.
The Red ignition light did come on, I didn't hear any ticking, should it tick when the ignition is on, or only when it's turning over?.
I checked the rotor arm and dizzy cap, they look OK, but I am not sure how to test them. I haven't had the car long so I don't know how old various bits are, the service history is non existant.

[Packedup]

If you're feeling tight, then clean the points, check all LT wiring connections, pull the HT leads and give each one a good clean on the dizzy end (assuming it's push fit, not screw fit). Also (although lots of people disagree) try cleaning any corrosion off the terminals inside the dizzy cap, and give the end of the rotor arm a bit of a clean.

Worth checking the spring and carbon brush in the cap are in good condition too.

Did you try testing for a spark direct out the coil? If it's good, then you know the fault is in the cap, arm leads or plugs.

[Willie]

Yes, the pump will usually tick a few times when you start up each day as
it fills up the float chamber. The mystery switch sounds like my sort of anti-
theft device, if one side is connected to earth it was probably connected to
the ignition low tension circuitry somewhere which would mean that if the
switch was 'on' there would be no spark as the effect of the points opening
would be nullified( the spark occurs when the points open). Simplest check
is to switch ignition on and flick open the points with an insulated screwdriver
when you should see a spark. If you do then the basic supply through the
primary winding of the coil is ok up to the points. If you do not get a spark
you should pull off the white/black lead to the side of the dizzy and,with ign-
ition on flick it quickly across any part of the chassis where you should see a spark. If yes then the 12v supply is ok up to the dizzy and the fault lies in that
unit (points, capacitor etc). If no spark then you need to check for 12v supply to and from the coil terminals. You mention fuses,for future reference, no part of the ignition circuit OR the fuel pump is fed through a fuse.

[Velocemitch]

Sorted thanks guys, it turned out to be the fuel pump. The loose wire from the switch turned out to be from the fuel pump, it's a simple but effective immobiliser.
Would have been handy if the PO had told me about it though

[bmcecosse]

But it couldn't have been connected to earth ! Many Minors have switches in the feed to the fuel pump - but to earth that feed would cause a small fire!

[Onne]

If the switch was from earth to the pump, does it matter what polarity the car was? Not that electrics make any sense to me at all, i just wanted to report/ask.

[Willie]

ONNE, there is only one terminal on the pump, the 'live' one. The earth contact is made via the mounting bolts therefore, if the mystery wire was
connected to the live terminal and the mystery switch then connected it to
earth there WOULD be a fire as the PUMP IS NOT FED THROUGH A FUSE.

[bigginger]

I'd better find what I wrote last night about the supply to the pump and clarify that, I think it could be mis-interpreted.

[Onne]

Ok.. electrics aren't my piece of cake

[Velocemitch]

Either way it still works and it isn't a smoking ruin

I will have closer look sometime, but I am sure there were at least two and I think three wires coming off the pump. maybe it had been isolated from the body and the live was coming through the switch, or perhaps it's a non standard pump.

EDIT, I am confusing my lives and earth's here, the switch is obviously connected to earth, positive in this case.

Electric's aren't my favourite thing either but I bet you had all come to that conclusion already

[bmcecosse]

It would be difficult to isolate the pump from the body - the fuel pipe itself will make a good earth. There may well be an additional earthing wire from the pump just to make sure. Any switch would need to be connected between the feed and the pump, and NOT to earth. However - as long as it's going!