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MG Midget and Sprite Technical - Ignition switch not doing anything!

I am at the latter stages of a complete restore of a Mk III midget and I am working on the Mk II dashboard electrics, as the last part of inking up a new loom. My knowledge of electrics is getting better!, but I am totally frustrated as to why when I turn on the ignition switch (the car is not yet ready for starting as yet), I get no response. Any suggestions as to what/how I should be testing?

(Incidentally, there are a lot more issues I would like to have help with, but let's start with this one!)

Bob
R Clayton

Is the wire thats white with red stripe hooked up to the solenoid under the bonnet ... give it a tug and a shake, it could be scalely at the connection if its been sitting a while

Prop
Prop and the Blackhole Midget

Also....

Make sure the ground strap has a good connection at the engine and transmission, its a woven metal strand strap and close to the clutch slave cly.

Prop
Prop and the Blackhole Midget

Thanks for your response Prop

All wires and their connections are new, as is the solenoid. However, I cannot locate the earth strap you refer to. (I guess it got missed out when refitting the engine!!) In fact, I have purchased a new one and it arrived today and will be connecting it tomorrow!

Will let you know the outcome.

Thanks

Bob
R Clayton

Hi,

I assume that your getting the ignition warning light coming on, fuel gauge, wipers and indicators work?

Even if the engine strap is missing, you should get a loud click as the solenoid gets currrent. Worth checking the solenoid is earthed, newly painted bodyshells often don't provide a good earth path.


SR Smith 1

Hi
No ignition light comes on, or indicators, I am in the process of wiring up the wipers. The whole body has been repainted, so I will check the quality of earth contact of the solenoid.

Thanks

Bob
R Clayton

to be sure... run a temp jumper ground wire from the body of the solenoid to a good ground
Prop and the Blackhole Midget

Hi again,


You either have no battery live on the brown wire at the ig switch or the switch is incorrectly connected. Is the voltage regulator connected up?


SR Smith 1

Hi

I've checked the solenoid with the multimeter and there is a good ground connection.

With regards the voltage regulator, I replaced the dynamo with an alternator and redirected the wires that would have gone to the regulator, therefore doing away with the regulator (I followed the guidelines provided by MOSS!) Are there any checks I can carry out?

I have also converted the Tacho from positive earth. Is ther anything I am missing do you reckon?

Thanks for your continued help!

Bob

R Clayton

I had had issues with switches crapping out in the past, mechanics have told me a heavy key ring accelerates the failure, try a jumper on the circuits that are dead.
Bob Ketcham

First of all, if you haven't already done so, You should make a simple test lamp. Just use a length of insulated wire 2 meters long with croc clip at one end, connect the other end to one side of a 12v bulb, then connect the other side of the bulb to a 1 meter length of insulated cable, at the end of the cable make some sort of test probe, ie small screwdriver with wire wrapped around the shaft and the shaft wrapped with tape to insulate it, leaving just the end bare. You can then clip the lead on the battery -ve or +ve, depending what you are testing for, and use the probe to see if you are getting the correct conditions at various points.
Initially I would leave all the fuses out, put one in at a time, and test that circuit to see if everything tests ok.
HALL JOHN

Hi

Thanks for your suggestions, I'll do the tests shortly. Could it be related to the fact that when wiring up the Tacho, there are two white wires from the loom, one male, the other female, which do NOT have anywhere to connect onto the Tacho?

Thanks

Bob


R Clayton

Those wires take the ignition feed to the coil through the counting circuit in the 'proper' rev counter.

You dont have the same rev counter fitted to the car, that one counts revs via the green wire.

Whatever you do the car wont start unless they are connected to each other.

Other things you need to check for the state of play at the moment is be sure the live power to the fuse box is going in to the correct terminal and thus coming back out to the wire for the switch, I think one side of the fusebox is a common rail and the other side comes off on individual circuits

The switch needs the feed to be connected to the right terminal too, Haynes gives switch terminal numbers in some cases. I dont have mine handy to use right now

I dont have an original Midget fuse box to check with because I have fitted new blade fuses to each circuit but someone will be able to advise on that.

Here's my birdsnest, tidying in progress...


Bill1

Hi again,


The basic check is have you got 12v at the brown wire at the ignition switch? Maybe something is wrong where the voltage reg has been bypassed? Did you join all the thick brown wires together?


The red ig warning lamp is not wired via a fuse and it will still light even if all the fuses are missing!


The two white wires at the tacho should be formed in a loop that fits in a plastic block that slides over the stud you can just see under the bulbholder on the far side. This is an impulse counter type tacho that counts the pulses in the live supply to the coil. It doesn't register via the green wire, that is a fused supply.


I think a car this year only has two fuses, a battery live that does the horns and headlamp flasher. The second is switched via the ignition and does indicators, wipers, brake lights, gauges etc.


Regards Steve


SR Smith 1

There you go, I said someone would be along

Steve knows this version better than me

My car has 1966 wiring and its tacho pulses are read inside on a male and female connection on the back of it

This drawing may help explain the type I have

As yours doesnt have this set up, ignore me


Bill1

Hi both
I have checked and there is 12v at the brown wire at the ignition switch. I also checked the brown wires that were in the regulator and they are all joined together.

I do not have the Tacho plastic block you refer to. I guess it went missing during the removal from the old loom. Any suggestion how I might obtain a replacement?

Thanks

Bob
R Clayton

Hi Bill,


Maybe I'm being thick but I can't see the male and female bullets on the rear of the tacho in your pic?



Is there a small brass threaded stud sticking out thro a rectangular cut out in the body of the tacho?



I thought the bullet connected type was later than your car, unless you have ended up with the wrong dial.
SR Smith 1

No mine is right for a 66 car

The bullets on the back of the tach are;

second from left: insulated white female wire to a male bullet sticking out of the tacho's back

fourth from left: female insulated socket sticking out of the tacho's back feeding an uninsulated male on the white wire which then goes to the coil.

As for the missing unsulated loop plastic device try one of the people like Magic Midget or somesuch, I can't see a dealer (MGOC or LeaceyMG having them in stock, but ask)

Bill1

Hi,

Even more confused here now. Is the pic you posted not of the tacho we're talking about then? How come the white wires aren't hooked up then?


Btw I don't need any parts, I'm a 1500 owner.
SR Smith 1

the pic is of MY tacho not Bob's

The shopping advice will enable Bob to find his missing plastic block with any luck, wasn't aimed at you Steve

I know yours works

Or Bob could fit a tacho like mine to his car even, mine works with my electronic ignition system

;)
Bill1

Ahhhhhhhhh, it all makes more sense now!


He'll need the little goalpost shaped piece of metal that goes over the plastic block as well or it'll never work.
SR Smith 1

Thanks for your advice, I guess it would best to have a replacement tacho. Can anyone please advise on the model number suitable for 1970 Midget to accommodate the male/female white wires.

Thanks

Bob
R Clayton

RC - the limited information you've given is really confusing!
How come your tacho connections don't match the loom, is it a new loom? Also you mention you converted the tacho from pos to neg - yet this change was around the turn of 67/68 according to Horler so your car should be neg earth anyway. Can you give more details ?
If you want a 1970 neg earth tacho it's an RVI2430/01.
David Smith

Hi David

Thanks for your help.

My original restoration was on a MkII (GAN3/51577) midget, which had a 1275cc engine (Oct 1972)put in by previous owner. However the bodywork was shown to be far too badly corroded to continue, so the body was ditched and a 1970 MkIII (GAN5 88227G), body only, was purchased. The engine, dashboard, and other items were retained from the original MkII car.

I have fitted a NEW loom designated for a 1970 Midget and changed over the TACHO, as I was informed that it would have been for positive earth.

Regards

Bob
R Clayton

OK so a bit of a mish-mash of parts which may be challenging. With the wisdom of hindsight it may have been better to get it running with the dynamo and control box but we are where we are. You definitely need the tacho I quoted, see pic. Have you found any more wires on the new loom that don't seem to have a home on the car? Do you have a voltage stabiliser on the inside of the bulkhead?
I think you will need the later half-needle type of fuel gauge too. If you don't have a decent source locally I have spares...


David Smith

Hi
As a relative novice, it is certainly a challenge! I think I have a tacho available soon. I have utilised all wires in the loom at the rear, front, engine compartment and the dashboard, with none spare. There is a voltage stabiliser on the bulkhead, with the green wires connected. I have attached a pic of the fuel gauge.

Thanks
Bob


R Clayton

Here is the reverse of the fuel gauge.


R Clayton

I think that looks like a very late 1500 Midget gauge; this is the correct one. You may be OK though.


David Smith

too late to edit, but my last post is rubbish! No idea of the origin of that one, this is the correct gauge for 1970 - 74


David Smith

to be fair to Bob he did put in his opening post >>I am at the latter stages of a complete restore of a Mk III midget and I am working on the Mk II dashboard electrics, as the last part of inking up a new loom.<<

and the photo he put up shows cloth(?) covered wiring
Nigel Atkins

yes Nigel, and there are umpteen changes to electrics within each Mark, hence it being insufficient detail and my request for greater detail. What do you deduce from the loom covering?
David Smith

>>What do you deduce from the loom covering?<<
that it's recycled flex from an electric clothes iron - am I on the right lines????
Nigel Atkins

That is indeed a late 1500 fuel gauge, bu sheer coincidence I've just posted a pic of mine the Dash Refurb thread on here.



Does your car have the 7 gallon tank and the matching sender unit to go with this gauge?



SR Smith 1

The fuel tank and sender are new and were purchased for 1970 MkIII, unfortunately, I cannot recall the capacity, as it was purchased some time ago.

The loom was also purchased new, as shown in pic.




R Clayton

Bob have you got any ignition systems working yet?

That was what you started this with after all

I've checked with the switch positions you need

These numbers should be on the back of the switch by each tag

The brown (off solenoid live side) wire must be connected to tag number three

the white (out) wires must be on tag number two, this feeds the fuse box, alternator live etcetera

the white / red wire to the solenoid goes from tag one

I think we need to address this before we get bogged down

Bill1

Bill

I have had to swap the brown and white/red connectors around and the ignition light cones on when the key us turned on -success!! Thanks!

I don't know why, but my circuit diagram had brown going into tag number 1!

Thanks

Bob
R Clayton

So now what do we need?

White revcounter wiring needs to be connected either through the instrument or by connecting the male and females on the white wires

This will feed the coil whether the tacho is in the system or not

Have you got that far yet?

The swapped over white/red and white should have the solenoid turning the starter now
Bill1

Bill
There is feed into the coil and the solenoid has turned over the starter. Many years since that happened!!

Thanks for the help and guidance. The ignition switch is now functioning normally.

Having used this website for the first time, I wish I had taken advantage of it quite a while ago!!

I'm now off to connect the wiper motor and get the indicators working, all other features of the lighting system are working fine.


Thanks

Bob

R Clayton

This thread was discussed between 17/04/2014 and 21/04/2014

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