TR7 1977 Clicking sound when turning key

[Chris Hall]

Good Morning,

I wonder if anyone can give me some advice.

I have a 1977 4 speed TR7. Had it for about 5 years and never had problems starting before.

Now when i turn the key i hear a single load click which sounds like it is coming from behind the glovebox.

The battery is fully charged.

Any ideas what the problem could be?

Appreciate any suggestions!

Thanks

[RobH]

The click may be the starter relay pulling in Chris.  I assume the starter isn't turning so there are several possibilities.

The starter relay contacts may have failed. 

The connection from the relay to the starter solenoid may be broken.

The connection from the battery to the starter may be broken (unlikely but possible).

The engine earth connection may be broken.

The starter solenoid may be stuck.

The starter solenoid contacts may not be making a connection.

The starter motor brushes may be worn.

 

Turning the key operates a small relay which in turn powers the solenoid on the starter. The relay will click but not terribly loudly.  The starter is a pre-engaged type with a built-in solenoid which both throws the pinion into mesh with the ring-gear and operates a high-current contact to power the motor. That will make a loud clack if it is operating but the motor not running; usually you can't hear either over the noise of the motor.  

I suggest you could start by checking that  the engine is earthed  - it is not unknown for the earth strap to break or for the connections to be corroded. 

Next check that there is power to the starter motor solenoid connection (the thin wire) when you operate the key, if there isn't then the relay may be defunct. 

 

 

 

 

 

[HowardB]

Starter relay is at back of glove box beside the fuses. Its a blue colour unit in the later cars so assume its the same for yours.

[BusheyTrader]

I had the same issue a couple of years ago.

On my 5 speed there’s a wire in the connector block that would have gone to the automatic gearbox inhibitor switch that isn’t there!  (It stops the starter motor engaging when the automatic car’s in drive)  Since there’s no such switch in a manual car, it loops back in to the connector.

In my 5 speed DHC, it’s at the rear of the engine bay, above the bell housing.  The contacts had accumulated many years of crud preventing a decent connection to the relay.   All I was getting was a light click somewhere in the relay, but not enough to actuate it.  Cleaning it solved the problem.

Edited October 22, 2022 by BusheyTrader

[Topoff]

Another common fault I have found (twice now on 2 different cars) is the small wire that has a spade connector to the starter motor works loose.

Easy check.  Laurence.

[Chris Hall]

Thanks everyone for your replies. Much appreciated.

I had a look behind the glovebox and could see that the blue relay wasn't fastened up. It was just hanging loose.

So i screwed it back to its fixing, turned the key and the car started straight away!!

Maybe i was just lucky!! Might be a silly question but did fixing the relay to the screw hole act as an earth?

I'll check the spade connection tomorrow on the starter motor.

Anyway all seems good for now!!

Thanks again

Best Regards,

Chris

 

 

[BusheyTrader]

The relay isn’t earthed through its fastener.  It has a plastic casing which the fastener clips in to.

It sounds like you may have a dodgy wire connection which you’ve nudged in to better electrical contact.  The youngest of our cars are at least 40 years old now…

[Chris Hall]

Thanks for the advice. My car is 45 years old now!

I thought it was lucky that fastening the relay back sorted the problem out! At least it would appear that the starter motor is OK.

I'll check the wire connections from the starter motor and work them back.