35 replies to this topic

[Mini Cheddars]

1979 Mini 1000

I replaced the inertia type starter solenoid and the coil earlier today but have had a bit of trouble since which I believe is down to my solenoid wiring.

I have the starter motor cable bolted down to the bolt closest to the wing, red/white ignition wire plugged into the bottom middle, some brown wire plugged into engine-side bottom and every other cable such as battery bolted on to the engine-side bolt.

As soon as I connect my battery, the starter starts turning; even with the keys out of the ignition. Caused a bit of a calamity earlier as the car was in gear (handbrake is rubbish so I keep it in gear too) and it started driving itself! Which resulted in a crushed iPhone, toolbox, old coil and aerosol of brake cleaner. Whoops.

After a bit of undoing and re-doing the nuts for the solenoid cables, I tried turning the car over by key but I would just get a click. Turned out to be some rubber insulation melted onto where the starter motor cable bolts down to the starter motor. I'm now keeping my car out gear but the starter motor started up again.

What on earth could I be doing wrong? I took a few photos before and during the undoing of nuts and everything appears to be where they were but as soon as I connect the battery it fires up by itself.

Thoughts?

[Mini Cheddars]

I have swapped back to my old solenoid but although it tried turning over for a few seconds, once I switched off the ignition and tried again, all I'm getting is a clicking noise - which is the reason I bought a new one in the first place.

[dklawson]

There are a couple of wiring mistakes that could cause the situation you are experiencing.  Pictures of the wiring you have will help if you can post some.

 

The image below shows the basic Lucas solenoid wiring for the inertia starter.  The JPG shows a 4-terminal unit which includes a white/yellow wire used on cars with ballast ignition systems.  If your car does not have a ballast ignition system, just pretend the white/yellow wire is not in the picture below.

 

Succinctly, the white/red wire (misslabeled in the picture as red/white) comes from the ignition switch.  It will only be "hot" when you turn the key to the start position.  The main battery cable and ALL the brown wires go to the top threaded terminal.  The cable to the starter motor goes on the bottom post.  The mounting foot of the solenoid MUST have a good clean earth connection to the car's chassis.  When the white/red wire goes "hot", the solenoid contacts close with a "click" and that routes power out of the solenoid to the starter motor itself.

 

The picture below is for the later, square, brick shaped solenoid.  If you have fitted the earlier, round, pushbutton type solenoid, the modern reproductions are very poor quality and break very quickly.  If you have fitted the round solenoid, your problems may be (are likely to be) that the solenoid failed immediately.  Replace it with the square solenoid and your car should be OK again.  

 

[Mini Cheddars]

The image you posted of the square solenoid is the type I purchased. Your first image hotlink has failed unfortunately as I cannot see it.

 

I'll post a photo tomorrow as it's almost 11:40pm here.

 

My last efforts before heading back indoors was putting my new solenoid back on and getting a click. I then went to the starter motor, undid the nut holding the starter motor cable in place to pull back the rubber insulation that had partially melted earlier and did it back up. Connected the battery back up and although the car didn't fire up as soon as the battery was hooked up, as soon as I turned the key, the starter motor started turning (which is normal of course) but it wouldn't fire until I stopped turning my key. Then once it had fired up, turning the key to the 'off' position and taking the key out didn't stop the starter motor from turning. So I had to disconnect the battery immediately.

 

So in some cases, the solenoid is just clicking and in other cases the starter motor will start up by itself as soon as the battery is connected and not turn off until the battery is disconnected.

[dklawson]

It's late today and a good time to stop.

 

You did say you replaced the coil also.  Does your car have a ballast ignition system? (I suspect it does).  Wiring those connections incorrectly can cause several situations like you are describing.  If your car's coil has a pinkish wire and a white/yellow wire on it your car has ballast ignition wiring.  Let us know what wires you have connected to which terminal on your coil.

[Ethel]

Have you got a yellow/white ballast ignition bypass wire hooked up? If you have it could be on the wrong terminal and switching the solenoid as soon as you put the ignition on.

 

.....Doug's turn to get in first 

 

There isn't much to work through to function check - with only the screw posts connected to anything nothing should happen. If you put power to the right spade  terminal on the body it should click - as long as the solenoid body is earthed.

[Mini Cheddars]

Here are some pictures. I really do hope it helps.

 

Here is my new coil as I left it last night. Took the photos as soon as I got home from work.

 

 

 

And my solenoid connections. Starter motor cable on the left, battery cable on the right.

 

 

Going through old photos of my engine bay to look at my coil, I noticed I got some connections muddle up with the + and - so I sorted that. This is my coil now. + on the left, - on the right.

 

 

For reference, this is how I had my old coil. I don't think anything is different now.

 

[dklawson]

Thanks for the pictures.  Since you found and corrected wiring errors I suggest we focus only on the bottom two pictures of your new setup and ignore the ones above it and the final (bottom) picture showing the original (old) coil wiring.

 

The two pictures look correct to me.  Your coil and solenoid connections look fine.  That said, I have to ask why there are (3) wires on coil (+).   One white wire will be coming from the ignition switch.  Where do the second white wire and the red wire connect to? I don't want to focus on them at this time but I am curious about what they do.

 

The solenoid will "click"  when you turn the key to the run position.  That click is made by the contacts inside the solenoid closing to pass current to the starter motor.  If you hear the click but the starter motor is not turning, the next test is to have a friend turn the key while you use a multimeter or test lamp between the starter motor terminal on the solenoid and earth.  With the key held to "start" the solenoid should click closed and you should find voltage on the starter motor terminal on the solenoid.  If you don't, that says there is an issue with the solenoid... since you heard it click closed.  

 

If the starter begins turning and won't stop when the key is released, pull the small white/red wire off the solenoid.  If the starter stops turning, that suggests a problem at the ignition switch which is keeping the white/red wire "hot" when the key is off.  Repair of the switch is by replacement.  If pulling the white/red wire off does NOT stop the starter from turning, that says the solenoid contacts are stuck together.  You could open the solenoid up by removing the rivets, fixing the internal problem, and replacing the rivets with #8 machine screws.  However, if the solenoid is new... I would return it as defective.  I know it is new but new parts are sometimes bad as delivered. 

[Mini Cheddars]

The red wire leads to the distributor as I have one of those little electronic ignition dongles in there, and the white wire leads off to the rev counter.

 

Thanks for the advice. I'll try to get a friend round.

 

What threw me off as well was when the starter motor was turning by itself as the key wasn't in the ignition, I disconnected the red/white ignition wire and the thin brown spade wire next to it and the starter motor would still happily start itself up as soon as the battery was connected. Would that suggest the solenoid is defective as per your last paragraph?

Edited by Mini Cheddars, 01 April 2014 - 05:10 AM.

[Captain Mainwaring]

Could be, or it could be that you are getting a back feed off the coil somehow which is causing the solenoid to latch in.

[samsfern]

I had a relay get stuck in the on position once, just a thought.

[dklawson]

However, ealier cars that used the inertia starter and that solenoid (from new) did not have a starter relay, only the white/red wire going to the solenoid from the ignition switch.

 

The brown wires are all for permanently live, unfused circuits on the car.  The white/red wire is the solenoid trigger wire coming from the ignition switch.  If your starter motor spins when you connect the battery AND have the white/red wire disconnected, that DOES say the solenoid is bad.  With the white/red wire disconnected there is NO power going to the solenoid to make it "click" and close the internal power contacts.  The starter motor spinning with the white/red disconnected says the main solenoid contacts are stuck together.

 

Cheddars... does the rev counter work? I would be very surprised if it does. Smiths RVC and modern aftermarket tachs work with a single voltage sense wire connected to coil (-) where the white/black wire is, not a wire connected to coil (+). These tachs are looking for voltage pulses.  The voltage does not pulse on coil (+), only coil (-).  Earlier Smiths RVI tachs were current sensing and for them to work, power to the coil has to pass THROUGH the tach (one wire connected to the ignition switch continuing through the tach, and terminating at the coil).  For either type of tach, a single wire on coil (+) should not work.

[Mini Cheddars]

Cheers for that info, dklawson. I should be receiving two new solenoids today or tomorrow. At the very least I'll have a spare one, then.

 

The rev counter does work, yes. It's not a Smiths one. I can't actually recall the brand of it and I can't find a good photo of it. Black magic, maybe?

 

Six days until I go to Slark Race Engineering for a pre-booked dyno tune. I really do hope I get it sorted this weekend.

[dklawson]

Keep us posted on your progress.

[Mini Cheddars]

Update time.

I have connected a brand new solenoid but I'm still getting a click from the solenoid. At least the starter motor isn't trying to start itself up though.

Here's how I have the solenoid and coil connected.





I can feel the solenoid click closed as I turn the key if I put my finger to it so that would tell me it's the solenoid and not a stuck starter motor.

I am clueless.