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MG Midget and Sprite Technical - Ignition light & new starter solenoid

I have a 1975 1500 midget, recently acquired, which had a starter button fitted. It had problems when trying to start (ie it took many, many presses of the button to get any life out of the engine, then start the car) and as such i decided it *might* be the solenoid needed replacing.

Solenoid replaced, the car was taken for a test drive; worked fine. Two days later when i started the car, i noticed that once the car started, i couldn't turn it off with the key. When i did eventutally manage to stop the engine (by stalling it) the starter motor was still spinning, to which i disconnected the battery to stop this.

Originally i put this down the the new solenoid, and replaced it with the old one. However, once i came to try and drive the car, i found that;

The ignition light was on when the key was set to 'off', however turn the key to 'on' and the light went out (not even tried starting the engine at this point).

Currently the car has the new solenoid fitted (the light issue occurs now with either solenoid).

Can anyone give me a clue as to why the light is staying on (and presumably drawing a current from the battery)?

Any help will be very much appreciated as I've tried checking everything since sunrise today to sort and eventually given up....!

P Redfern

How many wires are connected to the solenoid, what colours and to which terminals?

How was the starter button connected?
Dave O'Neill2

step one is probably to unwire the starter button and get back to standard as it sounds like a sticky switch...
David Smith

Normally if the the ignition light stays on with the key not installed / off poastion, that is an indication that the alt,/dissy regulator has gone bad

but in your case I don't think that's the issue, with the aftermarket starter switch installed by the previous owner and the various issues you're describing that are non repeatable with appearce of being almost random I think the problem is in the starter switch on the steering column its self,the factory one not the aftermarket one

I think when the key is installed the switch mechinism its self maybe messed up, broken, cracked, stripped, wornout, ect ect and is crossing various wires at different points in a random fashion

like I.said...its just a gut feel I have based souly on what your discribing... I have no knkwledge or experiance to prove or dis prove my thoughts on this

prop
Prop and the Blackhole Midget

btw...does this have an aftermzrket starter aka...the joe iszuze style known as a high torque with its own built In selinoid

you made the comment that the starter may have been ingaged the entire time...im not sure thats possiable with the factor lucas starter...but ive heard crazier on these cars

prop
Prop and the Blackhole Midget

I've double checked the solenoid wiring as per a Haynes manual wiring diagram; seems to be correct;
Looking at it face on, you have;
1x Thick wire to battery +ive - top pole
1x brown wire, ring connector, also top pole
1x thin brown wire to the left tab of the top pole
1x tni brown wire to rigt tab of top pole
1x thick cable to the bottom pole (starter motor)

1x white & green wire to the right tab mid solenoid
1x red & white wire to the left tab lid solenoid

(The last two *may* be the other way round; I'm doing this from memory, however it does tally up to the wiring diagram so theres no wrong connections there.

Starter button is connected into the starter switch - one cable goes the the switch, the other to the main loom (unsure which colour though). As far as i can see there is no relay in this setup anywhere.

I've had the starter switch (key barrel) out of the dash and taken a look, however theres no loose or cracked wires on this; looks pretty new by all accounts (which i was hoping it was a crossed connection or something, but no).

One thing i should add is that I *think* it wss the starter motor continuing on after i stalled the engine out - in hindsight it may have been the alternator, which would tally in with what im hearing back about the alternator being on the fritz.....
P Redfern

im not sure thats right...

I dont know much about 1500s but I dont recall there being a thick brown wire on the top post of the selind...should only be cable back to the batt.....thats on the 1275

the white red should be on the side spade post...thats the starter signal wire

I agree...pull the remote starter out and I think you will have better luck figuring this out

I think something js crossed somewhere

the 2nd starter switch should not have allowed the starter to keep running...any chance its a full on-off switch and not a momentary on-off switch...ljke a door bell

is there any chance.you can photo your wiring set up for us...it would make the process much easier...to see what happening

prop
Prop and the Blackhole Midget

if the white red was on the wrong post...that could be a problem...as your facing it should be on the left the tab

but like I said.. I only know 1275s

as to the white green...I dont.know what that is...that sounds more like the positive side of the dissy or the coil

I just dont recall a white green wire on my selinoid

wait for others to chime in...dont take my word as fact...im going from memory on the 1275'

prop

Prop and the Blackhole Midget

The white/green feeds 12v to the coil when cranking, bypassing the ballast wire. (Not fitted to 1275)

The thick brown wire is the feed from the alternator.
Dave O'Neill2

Yes sounds like you’ve incorrectly wired the solenoid, specifically the bypass wire (White Light Green).

The later Midgets have a ballast resister bypass on crank. What this does is bypass the ballast when the volts are a bit low on crank to ensure the coil gets at least 9 volts. Without this on crank if the voltage drops to 10-11 volts the coil may only get 7-8 volts, which isn’t enough.

If it won’t stop running then the coil bypass (thin WLG) is connected to the battery side on the solenoid, which is incorrect.

Those brown wire connections don’t sound correct either. All browns (3) and the battery cable should go on the same terminal. Red / White is the wire from you start button. The bypass wire should be on the contact that looks like it’s between the two large bolts. This is because when the moving contact comes up it connects the battery, starter and the bypass. If you’re in doubt remove the RLG and get it cranking properly without it. Then the spare terminal is the one for the bypass. Or put a test light on the terminal and check it only lights up on crank.
Greg H

Hi,
I know next to nothing about electric so will leave that as some on here are very good on the subject and hopefully along later

as the car is new to you assume nothing about always check and cross reference how it should, same with any info (here, parts, parts catalogue, books ect.) you get check and cross reference it

Haynes also has errors and omissions, I think the wiring diagrams are usually OK as no one has said otherwise

moderns parts can be faulty, not heard that about starter solenoids though

previous owners wiring and fitments can often be poor or bad (but not always)

taking loads of photos, sketches and notes before and during any work is a very good idea (and even after)

I'm with David I'd be inclined (or would have before Greg's post) to revert back to standard starting off the standard switch to see if it's the added in switch and/or wiring

for a good, comprehensive source of reliable information the Driver's Handbook is excellent and only £8 - Ref :0058 - http://www.mgocshop.co.uk/catalog/Online_Catalogue_Handbooks_5.html

Haynes (possibly) for repair, Driver's Handbook for prevention

ETA: as usual someone posted whilst I was still typing mine
Nigel Atkins

Gees Nigel, you managed to get that Drivers Handbook in there. I think to date about the only thing that book hasn't got good advice on is a cure for cancer. I'm going to have to buy one so I can start checking up on all these claims. ;)

No MKIII Gan4 Handbook listed :(
Greg H

"I think to date about the only thing that book hasn't got good advice on is a cure for cancer."

Or fixing my drill :).
Lawrence Slater

That drill not fixed yet Lawrence? We are all waiting for a pic of the first hole you drill with it! Needs to be a good one mind - steel or concrete. Bit of softwood won't do.
G Williams

chuckle chuckle.

In for a penny in for a pound. Factory acceptance tests are always to the upper limit of the equipment. So if it's got a 1/2" chuck then it 1/2" steel or concrete. Pics just won't do, it's got to be video. Smoke and sparks aren'r as impressive in a photo.
Greg H

Wrong thread chaps. Btw. Inch flat bit in oak is much more of a test. :)
Lawrence Slater

Greg,
the (UK) GAN5 one has a supplement for Gan 4 at the back, the '64-'74 DVD I mention (less convenient than paper copies) has 12 different Handbooks on it covering UK, NAS, USA and CDN

a couple of times on here there been speculation to correct answer which are easily found in the good book

it's a reprint of the book you'd have got with your car when it was new in the glove box, well not in Spridget obviously

I've a list of the few minor updates I've found

getting an original copy for your exact model may be possible s/h but I don't think it's necessary as the reprints cover all very well

for the average Spridget owner it's a a lot more useful than a Haynes as it covers many more things that a driver/owner needs to know and is accurate


Nigel Atkins

This thread was discussed between 12/01/2013 and 13/01/2013

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