MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Starter mystery

'79 MGB, 75K miles. Starter solenoid replaced about 4 years ago.
For the last 3 months, occasionally (as in less than once a week) the starter would not crank when the key was rotated to the start position. Nice "click" from the solenoid, but otherwise no joy.
Until yesterday, pulling out the key and reinserting it, or just some good ol' anglo-saxon verbal encouragement would do the trick. Yesterday it plain quit, and today I attempted to trace the problem. I went to that fine mgcars.org electrical site and used their troubleshooting suggestions. headlights didn't dim when switching the ignition to "start"; putting the car in 4th and rocking backward didn't help; moving the battery lead to the output terminal on the solenoid resulted in an odd, brief whirr (but no cranking).
I restored the wires to their original places on the solenoid, hooked up the battery again, and got the worst of all possible results--the starter now cranks just fine. As far as I can tell, I haven't "fixed" anything.
What do I do now? Replace the starter and solenoid, ignition switch, and/or ignition relay? Park pointing downhill?

TIA for your suggestions.
Chris Foleen

"and got the worst of all possible results--the starter now cranks just fine." Some people would disagree. Is it fixed? No, but it works!

It sounds like you have an issue with corrosion in either the starter or solenoid. A thorough disassembly, cleaning, and lube may be all you need to once again be reliable.

Or maybe Mr. Lucas's ghost has come back to haunt you for decades..
Jeff Schlemmer

We just had a similar problem with my wife's Miata.
[Sorry!]
But she said it had no click, whirr or any lights. We came to her resucue with jumper cables, a trailer and a tow strap.
Well the car was in a place that we couldn't do anything, so pushed it down a gentle incline, she stepped on the brakes, and I saw the brake lights come on.
So I asked her to try the starter again, and it took right off.
Go figger!
When we got it home, I pulled the cables off the battery, found light corrosion on the positive terminal, and she hasn't had any trouble for 2 weeks now.
I would suggest you start with the battery cables to be sure there is no CORROSION between the clamp and the battery post.
It's amazing how little will break the connection.
And yes, your lights will come on, the horn will blow, and other things operate, but the starter won't operate.
After all, it takes about 200 to 600 amps to operate.

Safety Fast
Dwight

Dwight

Chris. Next time it happens, hook a long jumper wire to the main terminal of the starter, then run it back to the passenger compartment. Connect to a volt meter and try to crank the engine. I have had this problem three times over the years. Once was the positive ground battery terminal which was one of the aftermarket type with a strap and two bolts to hold the cable in place. Bolts had come loose and there was no good contact. Second one was a bad cable from the positive terminal to the starter. Third one was a bad ground cable. All showed the same indication--three to five volts indicated when the starter was engaged, not sufficient to turn it over.

If you get low voltage at the starter, check the battery terminals as you are cranking. If they show low voltage, you have a bad battery. Then, check at the clamps. If the battery voltage is good and the voltage at the clamps is low, you have a bad clamp or a corrosion.

If there is good voltage at the battery and terminal, but not at the starter, jumper the negative terminal to the frame and try again. If all is good, bad ground from the battery to the frame. If the voltage is still low, bad cable from the battery to the starter.

As others have mentioned, connections and corrosion are always the first places to look.

Les
Les Bengtson

Well guys, you've given me some hope. I'll definitely go through all the connections and make sure all are clean and tight, and then test as Les has suggested.

I'll post my results (probably after the weekend) and let you all know how it went.

Thanks again!
Chris Foleen

Many times, if you have a bad connection, you can find it by feeling for a warm part at the likely places. If it ever messes up again, it's a place to begin. Maybe it will happen in the parking lot of the parts store, so carry a wrench or 2 along.
Tom

If the lights *do* dim when you turn the key to crank and all you get is a click (sometimes a chattering) then there is insufficient power getting to the solenoid, possibly because of bad connections or a flat battery, or just possibly that the motor *is* powered and *is* trying to turn the engine but some other mechanical problem is preventing it fom turning.

No dimming shows that power is *not* being applied to the motor and it is not trying to turn the engine. This can be bad solenoid contacts, bad motor segments or brushes, or possibly a bad starter relay and what you are hearing is a click from the relay and not a clonk from the solenoid.

As to what it was, you have probably disturbed the fault and it will come back again, in which case a bit of drivers seat diagnosis will help.
Paul Hunt 2

I had a similar thing happen last week. My situation was that the starter worked fine as I cranked, but the engine did not catch and did not start; so I cranked it again, only to just hear a "click" and no starter. I took the starter off the car to investigate (really a very simple job). I used jumper cables from a battery and connected the Neg to the starter mounting bolt flange ( an easy place for the cable to clamp onto) and then touched the Pos cable to the lead that comes out of the solenoid and goes to the starter itself. The starter spun nicely, telling me that the starter is fine, if its getting a good contact. Next, I touched the Pos cable to the spade connector on the solenoid. This caused the starter gear to throw forward as if to engage the flywheel ring gear. I therefore knew that the solenoid was working. Next, I connected the Pos lead to the other large, battery connector on the solenoid and used a small jumper from there to the spade connector. This caused the gear to throw forward and the motor to spin. I concluded everything was fine - more or less.

What I deduced fromr this testing is that there is an emerging problem with the internal contacts in the solonoid. When the starter stopped working, both you and I heard a "click." This noise is the solenoid doing its thing and throwing the gear forward which is supposed to also close a contact between the two solenoid terminals where the battery cable terminal connects to the lead into the starter motor. It is the contact between these two terminals that wasn't closing. I believe that in both of our cases, the contact is begining to get a little worn or corroded and is starting to be a little dodgey. I simply reinstalled my starter and took the car out for a ride on a beautiful warm autumn day. But I know I will have to deal with the problem. Since removal of the starter is a simple matter, I inted to take the solonoid off and remove its end cap and inspect, clean and adjust the main contacts, if possible. If not, replacing the solonoid is straight forward (a new one costs about $50) and would save the worry over where and when it will decide to quit again. Another temporary solution if stranded is to use a hammer and bang on the solonoid gently, trying to make the internal contact plate shift a little and hopefully do its job.

Good luck
David Burke

I promised to report back after implementing your suggestions. I cleaned all connections, tested the battery and voltage as Les suggested, and all seems well. I have had no recurrence of the problem so far.

From my earlier experience that led to the replacement of the solenoid, I always have a soft-face hammer I the boot to encourage good starter behavior if necessary.

Thanks everyone for the advice and encouragement!
Chris Foleen

This thread was discussed between 10/10/2005 and 20/10/2005

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.