Starter motor re-engaging after start

[Ron McC]

Hi All,

Got a problem with my 3000M turbo, I could start the car, engine fires up, then the starter motor would re-engage with the flywheel with the
engine running. No problem, I thought, the starter motor was getting to the point where it was slow to crank the engine even with a fully charged battery and its been on the car for decades, time for a change. Got the down pipe off, disconnected the wiring, elect cables connections cleaned up, new starter motor fitted, elect cables connected, down pipes refitted. Tried to start the car, no cylinders firing, getting a good spark but no fuel. Took the top off the airbox, primed carb with fuel, turned the key, car eventually started then the starter motor (new) re-engages with the flywheel after a few seconds. Back to square one. The starter solenoid is obviously getting an electrical signal to "start" whilst the car is running. Could this possibly be the ignition switch on the column?? Which to be fair does have a bit of slop.

However, all this has came about when I found this electrical item broken. I got it soldered and it seems to be working fine, as the car now starts but I can't help wondering if this is part of the problem

All help gratefully received.

Ron McC

[Ron McC]

Just to add on to the Topic above, Got engine started, same problem, starter engages while engine is running. Disconnected the alternator, primed the carb with fuel, car starts although no charge to the battery, but the car sat there and idled without any problems. Reconnected the alternator, started the engine, within seconds the starter re-engages with the engine running. Could it be the diode pack in the alternator is faulty?? Or a dirty earth somewhere?

Regards,

Ron McC

[Adrian@]

Ron, you need to contact me direct, (not on an open forum as posting the reply here will confuse and muddy waters) for your safety you need to keep the diode system (nothing to do with the alternator) working as it should. BUT yes the starter WILL run if it is not wired correctly (I have a wiring diagram on my FB page in PDF)...I am on .........(I will delete this last bit as soon as you contact me). A@

Edited by Adrian@ on Thursday 1st June 16:16

[Polly Grigora]

Ron McC said:

However, all this has came about when I found this electrical item broken. I got it soldered and it seems to be working fine, as the car now starts but I can't help wondering if this is part of the problem

All help gratefully received.

Ron McC

If you're sure that the diode shown in the image is working correctly and not short circuit.....

What's happening is that the alternator D+/61 warning light output is powering the starter motor solenoid through the diode once the alternator cuts in and is charging

A correctly working diode will prevent the alternator D+/61 warning light output from powering the starter motor solenoid

Wiring a good diode the wrong way around will cause the problem you are experiencing

(A faulty short circuit diode will also cause the same problem)

---

Have a hunch

Has someone wired the starter motor solenoid circuit and alternator warning light circuit into an electric fuel pump circuit

Read below if answer is yes

The alternator D+/61 warning light circuit can't be used for driving a fuel pump circuit, this method isn't safe

It will be worth your while to delve deeper into the cars electrical circuits to ensure that the fuel pump circuit is not driven by the alternator warning light circuit

If your car doesn't have an electric fuel pump......Ignore me

Edited by Polly Grigora on Saturday 3rd June 09:52

[Adrian@]

Smile gracefully...as ever Polly muddying waters...He does not own a TVR (let alone one of the 64 that have 3 different wiring loom versions over the build period). A@

Edited by Adrian@ on Saturday 3rd June 17:00

[Polly Grigora]

Hi Adrian, thank you for the quick reply

The problem with using D+/61 to drive a fuel pump circuit isn't a problem when the alternator is functioning correctly

What many people overlook is how problematic alternator rectifiers can be

When alternator rectifiers fail they often apply a positive voltage of 3 plus volts to the D+/61 terminal even when the ignition is switched off

The majority of automotive 12 volt relays although requiring 9 plus volts to pull their contacts to the closed position only need 2 to 3 volts to hold those contacts closed

Anyone that thinks driving a fuel pump circuit from D+/61 is a solution to a problem has overlooked the above

This is why I posted here, it stood out like a sore thumb to me that a faulty alternator diode or 2 would be a massive fire risk

A person could park their car up get out and lock it not knowing that an alternator diode had gone short circuit causing the fuel pump relay to hold-in and run the fuel pump

What's worse still is the fact that the car is parked up and there is no under-bonnet air flow, engine hot....possible fuel vapor.....fuel pump running until battery goes flat

Now you and hopefully others know, this is the most important thing

[Adrian@]

Polly, rubbish, tosh...I have not been without at least one TVR turbo in 32 years, AND, I had two major accidents where the TVR system saved my life. I also purchased a TVR turbo and rebuilt the car back to OE that had been fitted with a dedicated fuel pump control system, which ended up with the passenger (the owners wife) being sat in a damaged car with the pump still pumping (the pump is behind the passenger in the chassis). Your post is the exact reason I asked to move the OP off an open forum. A@

Edited by Adrian@ on Sunday 4th June 09:33

[Polly Grigora]

Adrian@ said:

Polly, rubbish, tosh

No, please, have posted the facts

Alternator warning light output D+/61 can't be used to control a fuel pump circuit, the method isn't safe, all is explained above

Using the vehicles oil warning light pressure switch is safe, It's safe because it's a switch On or Off (nothing like D+/61)

A Tachometric relay will do the job

Adrian, apart from short circuit alternator diodes holding the fuel pump relay in....

You've also overlooked another fact

If the alternator goes off charge the fuel pump will cut out

[Adrian@]

Again Polly, you are wrong...OR 3 of my TVR's would not be running. My current turbo has been wired as OE since new (1979) , I have known the car since 1988 and owned it since 2000. I have added the same system to two of my own current cars, and back when, installed it on many, many cars. I have had enough on the subject, so will not reply...A@

Edited by Adrian@ on Sunday 4th June 20:20

[Polly Grigora]

Adrian@ said:

Again Polly, you are wrong...OR 3 of my TVR's would not be running. My current turbo has been wired as OE since new (1979) , I have known the car since 1988 and owned it since 2000. I have added the same system to two of my own current cars, and back when, installed it on many, many cars. I have had enough on the subject, so will not reply...A@

Edited by Adrian@ on Sunday 4th June 20:20

Adrian@ said:

Again Polly, you are wrong

Nothing of the sort Adrian, there's nothing to be wrong about, I've posted the facts above and they are correct, the problem is obvious to many and easily solved by using the oil warning light pressure switch for the run signal rather than the alternator D+/61 warning light circuit

Adrian@ said:

My current turbo has been wired as OE since new (1979) , I have known the car since 1988 and owned it since 2000

In which case your car has been wired incorrectly for at least 43 years

Frightening isn't it

Adrian@ said:

I have added the same system to two of my own current cars, and back when, installed it on many, many cars

You do surprise me

Did you not once even consider the big mistake that was being made?

All those cars that were wired incorrectly should have been called back to the factory and put right

Adrian@ said:

I have had enough on the subject, so will not reply

Do you not think it would be beneficial for the owners of the many incorrectly wired cars to be made aware of the problem?

I do

Fortunately PH TVR is very popular and others will hopefully read through this topic and then be aware of the problem and solution

Still find it hard to believe that nobody else has mentioned this problem in the past

[GeneralBanter]

I had a fauly solenoid which led to the starter continuing to turn when the engine was running which in turn led to the car catching fire. Nearly lost the V6 Tuscan but for it being a very sort local trip.

[Polly Grigora]

GeneralBanter said:

I had a fauly solenoid which led to the starter continuing to turn when the engine was running which in turn led to the car catching fire. Nearly lost the V6 Tuscan but for it being a very sort local trip.

What difference did the trip make?

[GeneralBanter]

Polly Grigora said:

GeneralBanter said:

I had a fauly solenoid which led to the starter continuing to turn when the engine was running which in turn led to the car catching fire. Nearly lost the V6 Tuscan but for it being a very short local trip.

What difference did the trip make?

Not much, saw some geese and a tractor though.

Edited by GeneralBanter on Sunday 11th June 08:48

[Polly Grigora]

GeneralBanter said:

Polly Grigora said:

GeneralBanter said:

I had a fauly solenoid which led to the starter continuing to turn when the engine was running which in turn led to the car catching fire. Nearly lost the V6 Tuscan but for it being a very short local trip.

What difference did the trip make?

Not much, saw some geese and a tractor though.

Did you manage to put the fire out because you were at home?

[GeneralBanter]

Polly Grigora said:

GeneralBanter said:

Polly Grigora said:

GeneralBanter said:

I had a fauly solenoid which led to the starter continuing to turn when the engine was running which in turn led to the car catching fire. Nearly lost the V6 Tuscan but for it being a very short local trip.

What difference did the trip make?

Not much, saw some geese and a tractor though.

Did you manage to put the fire out because you were at home?

It caught fire as as I was returning home, had to jump level crossing lights and put it out in the road outside my house.

Edited by GeneralBanter on Sunday 11th June 16:05