Morris Minor Owners Club

For about a month now I am having electrical problems with my completely restored 1965 2 door saloon.
The car was fine untill suddenly the fuel gauge dropped to 0 and the indicators did not work at that same time. This lastet a few seconds after which the fuel gauge ran up again and minutes later it dropped again. This went on and on during the drive and always the indicators flashers did not work when the fuel gauge was going down.
First I thought of a bad earthcontact somewere (negative is earth on my car), but I could not find anything.
I checked the fuses and swapped one of 10A for a 35A as should be according the manual. I cleaned and softly grinded all connectors at the fusebox and controlbox and after that I had a week (daily driver) without any problems.
But than the problem returned and also the IGN light went on every now and than when the engine went to iddle speed on corners, roundabouts, traffic lights etc.

A friend of mine (a former mechanic) helped me out and according his meassurements the control box gave 16V, which was very high, he said. I replaced it with a spare control box and again I had no problems for about a week.
But mr.Lucas is playing tricks on me, because the problems returned and were again increased. The IGN light went on much more (besides the failing fuel gauge and indicator), but worse the engine ceased. It suddenly stopped and it would not start after some long long attempts. This state continued: sometimes it started first attempt and the next time it had big problems starting. Due to the sudden stop of the engine and my electrical problems I reckoned the coil did not get any or enough current.

With the wiring diagram in hand I found out that all these elements that have failure in my car are alle connected to one thing: the ignition switch. I checked the wiring from the big connector on the dynamo (D on the diagram) throught the IGN lamp and ignition switch to the fusebox.On that point in the fusebox a wire goes to the coil and fuelpump and on the other end of the fuse it goes to the indicatorswitch, indicatorrelais and fuelgauge. So this looked the place to search for me.
But no bad connectors or bad wires in this part. I replaced the ignition switch for it was quite worn, but no approvements.
The car starts badly most of the times and when I drive away it looks like it wants to cease. It splutters...
Also the oilpressure light flashes on every now and then and not the IGN light anymore. I checked whether I had swapped the two when I had the speedometer out, but that was not the case.

A long story but as you can see I have tried to solve the problem with my few knowledge of car-electrics without result.
Hopefully you guys can help me out... But be patient with me, because of my bad english (especially the technical terms) and my bad knowledge on this subject...

Freddy
Nothing wrong with your English !
Battery ? Was this a new battery, fitted recently or the old battery.Are the cells filled with the right level of electrolyte / distilled water.
Is the fan belt adjusted correctly,no slack...not slipping ?
Are the connections to the battery clean and tight ? Are the big main "earth" straps ( braided cable ) clean and tight.These are the ones by the front of the engine to the engine mounting tower and by the gearbox.
If all these connections are good, together with the work you have done, you can look at the charging system.

Do you have a multimeter ?
The battery ..in the morning before you start the car..should have voltage of about 12 + volts(12.6 volts for a new battery ).Once the car is started, rev the engine up to a fast tickover and measure the volts again, whilst the engine is still running.It should read between 13/ 14 volts.With the engine running fast and electrical equipment on e.g headlights, heater fan, etc, it should still read 13 volts.KEEP ANY LOOSE WIRES AND CLOTHES AWAY FROM THE FAN, BY THE RADIATOR.DO NOT WEAR A METAL WATCH OR RINGS WHEN DOING ELECTRICAL WORK ON THE CAR.
It maybe that the battery is not retaining it's charge and is" running" down the power or that the system is not replacing / topping up the power correctly.You've replaced the control box, so it maybe the brushes in the dynamo that need replacing and the dynamo commutator cleaning.
Let us know how you get on and what you find.
Bob

I agree, your English is brilliant. Welcome to the forum.
You are on the right tracks where you are looking. Did you replace with new fuses because I have had a case with these glass fuses where they look okay, test okay with a meter but break down under load.
Does anything else fed by the green wires on your fusebox fail, ie wipers, brake lights, heater?
As suggested new dynamo brushes may help with your ignition light problems.
I also had a case where the fuel gauge stopped working after I removed the speedo and I worked out that the only way the gauge is earthed is via the 2 screws that hold the speedo in so I fitted an extra earth wire to earth the speedo. This could be the oil light problem as well.
I know you may well have done this but check all control box wires for a good connection, likewise all the fusebox wires.
Let us know how you get on.

Hi Bob and Beero,
Thanks for the replies and the compliments about my English ! Luckily all the Dutch have to learn English thanks to our education system, but especially the technical terms are still quite unknown to me.

Anyhow, today I meassured the things you said and no odd numbers there, I think, but then again the electrical problems did not appear when I was doing the meassurements. That's one of the main problems with these now-and-then-electrical-problems...
Here are some numbers:
Battery without starting: 12,69 V
Battery idle speed: 14,4 V
Battery engine running fast: 14,8 V
Battery with lights, heater etc on: 13,2 V
Dynamo idle speed: 13,5 V
All number are "about" numbers because it changed constantly of course. As said, these numbers do not look odd to me. I will try to do the same when the problems appear.

The level of batteryfluid could be topped a bit but all plates are still beneath electrolyte. Also the connections to the battery are new and clean. But I noticed that there was no earth-strap on the engine itself, but there was one on the gearbox. Is that sufficient?
Since the problems did not appear while testing I can not say whether the brakelights, heater and wipers worked or not, but I assume that they do not function while the problem is there, because they are connected to the same fuse as the fuelgauge and indicators....

Maybe I will swap the dynamo with one of my other moggies this weekend and see if it makes any difference, or do you think that will be pointless?
Regards,
Freddy

The battery and dynamo are fine - don't touch them!! I would very carefully check and clean all the connections at the solenoid - and at the voltage regulator (A and A1 connections) . You could try a temporary link from the A to A1 connection too - just to see if the problem goes away. You have done a good job so far checking - but check again. The red Ign light coming on at idle is quite normal - and also possibly the oil light can flicker at idle if the pressure is a bit down with a hot/worn engine. Once you sort out the electrical problem - seriously consider an oil pressure gauge. When you say 'problems starting' - do you mean the engine won't spin over -OR - it spins over ok, but won't fire up?? And errr - it's NEVER the coil.......but it can be coil connections - so check them carefully!

If you have 13.2 with lights on and 12.69 when not started then there is nothing wrong with your dynamo or control box so look elsewhere. An extra earth strap to the engine will do no harm at all, it will help if your engine is not turning over fast enough on the starter.

Freddy
I agree with Roy ( bmcecosse ) and beero.Charging side is OK.Fix the correct earth strap to the front of the engine, to make starting better.
If you Goole "images " ...looking for a picture of " Morris Minor earth strap " , a few rows down on the results, you will see the strap bridging the rubber engine mount.One end to the side of the engine and the other under the bolt, holding the metal tower
mount to the body.
After cleaning the main solenoid connections, as Roy suggests, ( with the battery disconnected ,of course) if it still makes no difference i.e. you still have the problem, then some more testing is required.

From the wiring diagram you will need to follow the wires for each component from the fusebox.Everywhere there is a connection take it apart and clean the connection with emery paper.. to get nice clean metal.
With the ignition ON and your multimeter set to "volts" put one end on a good earth on the body ( a convenient earth ) and the other end on the wire coming from the fusebox.
You should see " full battery voltage "...that would be 12.69 volts if the test was done on the same day as you took your readings.Switch the ignition OFF...do not leave on for a long period.Move along the wire checking each connection to the end.
Excellent work so far... you are gradually eliminating the problems and you car's electrical system will be much more reliable in future.
Bob

Thanks again fo all the replies. It helpes me out and besides that I am starting to understand car electrics. Before I was kind of "afraid" to handle electrics on my cars and motorbikes, but now I am getting to like it
The engine spins over fine while starting, but won't fire up. Therefor I reckon that the solenoid is fine, because it gets its current from a different circuit than where I am having problems in. I presume the coil does not get any or not enough volts to build up the high voltage, so it won't fire up. And that coil is also connected to the same problemcircuit.

In my humble opinion the problem can be three things, but correct me if I am wrong:
1- failing dynamo
2- bad contacts in the wiring from dynamo to fusebox
3- bad eathcontacts

I checked the earthstraps from battery and gearbox. These were OK, but I will connect the engine with an extra earthstrap.
The wiring from D on the dynamo untill the fusebox was checked. I disconnected each wire one by one and connected one side of it to the + on the battery. On the other side I meassured the voltage and all were ok, even when I fumbled the wires.
So everything looks ok, but it is worth a double check. For that I am thinking of rewiring this circuit from D on the dynamo through the controlbox, IGN light, ignition switch to the fusebox with a temporary wire. It is only about 1,5 meter (5 foot)rewiring and it will be only temporary. If the problem is gone then I know that one of these wires is bad connected. If the problem is still there I know that I have to look somewere else. If the problem is gone I will reconnect the original white wire from fusebox to the ignition switch. Then a check again: do the problems appear, then I know that that wire is bad. If the problems are not appearing then I will reconnect the next original wire from ignition switch to IGN light, etc etc.

Sounds good to me, but the only problem in this method is that the problems might not appear, because it is not a steady problem, by meanings that it is not always there. But what do you think of this method?

My other questions are: can a dynamo function and on another moment malfunction? and as you can see my search concentrates on this particular piece of the electrical circuit. Am I right about that, or could the problems arise within the wiring further on (for instance the green wires to wiper, indicators etc or white wires to fuelpump, coil etc)? In my opinion the malfunctioning of these elements are all symptoms of the problem, but not the problem itself. Or am I wrong about that?

Looking forward to your responces again!
Thanks
Freddy

What style of battery connectors do you have?
The cap type can give all sorts of problems, clamp ones are much more reliable.

It's NOTHING to do with the dynamo! Leave it alone - look to the A and A1 connections on the voltage regulator.....join them with a short jumper wire...... And as the starter spins - it's not the battery either!!

I reckon I have clamp ones (you have to bold them on like on modern cars)

Roy, I will connect A and A+ with an extra wire. See what it does.

An update from this afternoon: I rewired the circuit from the dynamo throught controlbox, ignition light, ignition switch to fusebox. I expected the problems to be in that section and with the new, temporary, wiring I hoped to get around the problems. And it did! No IGN or Oilpressure light; no failing fuelgauge, no malfunctioning indicators!

I will keep this temporary wiring for a few days to test it out. If the problems stay away I know for sure that the problems are within this section. Then I want to go back to original wiring one at a time, like said before. With that I hope to determin the exact wire which causes the problems.

For this moment the car looks reliable again, so thanks everybody for your comments and advises. Could not do without them!
Ta
Freddy

Do the Ign and Oil light still work ok when you switch on the ignition - before you start up?

Yes, they do. They light up when you start the engine and after a short while they go out and during the ride they never lighted again. So everything looks fine now.

Well done.

Well done Freddy, you are getting there. With every success you will come to like car electrics.

Will be interesting to know what the actual problem was......