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My Daughters MG tf keeps failing to start, it's not battery and I have checked the earth at the battery.
All the dash lights come on, turn the key and nothing.
She stopped for fuel the other day, got back in car and nothing, she calls me out, I get there turn key and it starts.
Last night she got back to her car after work and couldn't start it, we picked her up and I went back this morning to collect
it,turned the key a few times (it was dead at first) then it spung into life.
I've been hoping it would fail completly as that will be easier to find, my guess is either the starter or it's connections
any other ideas welcome?

Some friends had an issue like this on their F last year. They went through the process of changing the battery, the solenoid, cables and other assorted actions including checking and cleaning earth points etc. It turned out to be a dodgy winding in the starter motor. The position it stopped in would determine whether or not it would turn the next time.

My F would often do this, it turned out to be the low voltage wire on the starter solenoid, I used to wiggle it and it would go straight away. Have a look and see if it's slack, it may solve your problems, it's the wire in the middle by the way, you can see it from inside the boot looking down through the grille with a torch.

Hi. You might try the umbrella trick. Open the boot and remove the grill above the engine. Look into the engine bay and locate the SM on the left of the engine. While someone else turns the key tap the SM with a suitable long instrument. I have used a small heavy hammer in the past. It does not have to be very hard. Just a tap. Eventually I had to have the SM replaced.

Why the umbrella trick? The first time it happened at a meet many years ago they used a spring loaded umbrella to tap the SM to start it. No hammer available. Ash

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As Ashley says, occassionally the solenoid sticks. But I'd go with your suggestion of ensuring that all the connections to the starter motor are clean and intact, and that you have a good quality earth.

BTW, when you're attempting to start, is the starter relay clicking as it should?

Thanks for a few pointers, no no click from solenoid, completely dead.
If it's dry tomorrow I'll have a look at the connections on the starter

The earth lead between the engine and gear box is also worth a check if you are getting no click on the starter. The contact on mine was poor and the brake down service cleaned it up and the car fired first time and every time after that. That was a temporary fix which is still going strong.

I second Adrian's advice about the switchable 12v feed to the starter. The lucar connections are probably corroded. You can reach in and do it from the boot grille as a get-you-home, but it is worth a good clean.

As many have suggested already, we'll worth checking the spade terminal to the starter solenoid first. If this is ok, and you still have problems, no click when the key is turned then it could be an ignition switch problem. There was a part change point that is not detailed on official parts catalogues, that occurred roughly at the time when the MGF became the the MG TF, with the type of switch fitted. The earlier type switch had a short wiring loom as part of the black plastic ignition switch screwed to back of die cast lock barrel, this was replaced with a switch assembly with no wiring loom - the wiring just plugs straight into it. As I said there seems to be no record of this, but the same set up was used on the MG ZR, and a parts information is used for this application, so the replacement switch part number is YXB100350A. Failure of this switch has become common enough for us to keep one in stock.

If the fault is happening frequently, you could run the car with the lower ignition cowling removed, if it won't start, keep the key in the crank position and with your other hand give the main wires plugged into the switch a wiggle, this usually makes it burst into life, answering the question!

A second much rarer fault is a partial failure of the ignition supply circuit, which can result in momentary loss of power steering as you are driving along!

The 12v spade terminal failing is a common K series problem.

Thanks to all for the various suggestions.

Here's what I've found today.

1. There is +ve 12v supply to the 80A fuse in the engine compartment verified with a 12v bulb on a lead to negative earth.
2. There is +ve 12v supply to the solenoid in the engine compartment also verified with a 12v bulb on a lead to negative earth.
3. I've wiggled the connectors to the starter and solenoid and none appear significantly corroded.
4. Suspecting the earthing of the engine from perhaps a corroded engine earth strap (I couldn't see it) I tried a supplemental earth by using jump leads - one end to an earth point and the other to a gearbox case bolt.
5. I took off the ignition switch cover and unplugged, examined and re-plugged the ignition switch connections. I didn't notice a loom behind the switch, but it's a 2002 so might be early enough to have the problematic switch.
6. I have no power to the glove compartment light. All fuses are in order and everything else on that circuit works, but I wonder if a short here caused the fuse 8 failure which is why I started the dismantling and seemed to have caused the non-starting.

So I am still getting total silence when twisting the ignition key (no relay or solenoid noise) and an illuminating high oil temperature light. Does anyone know if there is a relay that drives the solenoid power or is there a direct connection from the ignition switch to the ignition solenoid?

Best regards,

Daniel

Best regards,

Daniel

Replied in viewtopic.php?f=8&t=19940

Hi, I have a similar problem on a 1997 VVC. The car had been standing in a garage for 2 years so new battery, the starter was sluggish so I disconnected the battery -ve and cleaned all the connections: the spade terminal was rusty and a loose fit. Reconnected the battery -ve and the starter won't turn, the lights don't dim but like the previous person, the high oil temperature light is illuminating. Does this signify anything?