Mystery starter motor operation

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Mike E (uk)
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Mystery starter motor operation

Post by Mike E (uk) » Sun Feb 12, 2006 7:11 pm

Hi,

In the supermarket car park, the starter motor would not shut down after use. I was not turning the key to start.

It was spinning round, but not turning the engine.

I removed the ignition key, it still ran!

then I removed the wire that goes to the solonoid.
I did this in the loom, not at the solonoid , as it is hidden.

It still ran!

I had to remove the fat starter/alternator wire to stop it.

The two wires on the solonoid were not touching.

Bump started it, and drove home with it disconnected.

I have now removed the starter motor, and it works fine on its own.

I suspect the ignition/starter switch, but :

1. How did it spin without turning the motor over?
2. Why did it not stop when I disconnected the solonoid wire?

I can not fine anything wrong with the rest of the car, though the key switch may be intermittant - I have not detected this. The wiring to the solonoid is not stuck at +12V.

What is going on????

Mike

Stewart (oily!)
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Post by Stewart (oily!) » Sun Feb 12, 2006 7:25 pm

Sounds like something broken or sticking in the starter itself, once the solenoid has travelled its distance it makes contact and the motor turns, hopefully engaging with the flywheel, the contacts are permanently live so if the solenoid sticks or something is loose in there your symptoms might happen, try cleaning the pinion and spiral bit with some solvent and a paintbrush then replace it without lubrication, if it does it again a new starter is probably in order.
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Post by jeremy » Sun Feb 12, 2006 7:48 pm

I agree with Stewart. I've never had a Citroen starter to bits but on the old Lucas ones there used to be a switch in the top of it operated by the solenoid itself which would cut the current to the coil once it was engaged. If this switchgear (main switch or any other parts of it) are sticking the motor will continue to run when the feed current (from the switch) is turned off.

Can we assume that no other part of the wiring has been touched recently?

jeremy

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Vanny
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Post by Vanny » Sun Feb 12, 2006 8:39 pm

is this the same starter you've had nothing but trouble with even after prolonging the inevitable with relays etc?

It might be time to bite the bullet and just buy a new/fully remanned one!

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Post by AlanS » Sun Feb 12, 2006 9:22 pm

Sounds like the solenoid contacts were welded together.
Solenoids internally are usually just two big silver terminals that a copper plate attached to a solenoid plunger zaps across when it is energised from the starter switch/ignition switch when the key is turned.
These work on the 12V low tension lead that comes straight from the battery. If power to the solenoid gets low due to degradation of wire, dodgy connections or contacts in the ignition switch starting to get worn or dirty, the solenoid tends to slOp in rather than slAp in with the result there is arcing at the contacts which is there usually, but when the full voltage is fed to the solenoid it is much less due to it slamming hard across the contacts. When the voltage drop gets to the solenoid coil, this means slower activation, bigger acring, contacts getting hotter and more burn and eventually, it gets welded to it. Once the car was jump started, the gear on the flywheel would have been jolted loose (as with a jammed starter) which would have caused the copper plate to break free of the contacts inside the solenoid and appear normal.
My guess is that the power supplied to the solenoid from the key directly would turn out to be around 9 - 10 volts which you'd find would drop substantially when the load of the starter was applied.
Solution I feel is like I have done; wire directly from battery to a remote starter switch, to relay and onto the starter solenoid. Chances are the solenoid will then get a second life, but no guarantee; might need to try to source another (known good) solenoid to be on the safe side.


Alan S
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Mike E (uk)
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Post by Mike E (uk) » Sun Feb 12, 2006 11:17 pm

Thanks for that onfo,

Vanny- this IS the new starter!

I have wired a relay via a fuse to the battery, and it has worked fine for over a year since that was added.

The starter is brand new, and looks it, but that does not mean it is OK for certain.

Perhaps if I refit it, it may work fine for years, but I don't want to get stranded again.

Perhaps a new battery would help keep the solonoid healthy?

Alan, the normal ignition switch removes power from all non-essential circuits when the engine is turned on the starter motor, do you achieve this with your remote starter switch, or just spin the starter with everything else connected normally?

thanks.

Mike

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Post by AlanS » Mon Feb 13, 2006 12:16 am

My remote switch turns off all lights on the dash as it starts - don't ask me how as I had my son do the wiring, but to my knowledge, it just picks up the wire that normally goes to the ignition switch/solenoid as I can still use the key as well.
Thing is, when I use the remote button, there's no load passing through the contacts in the ignition where the starter is energised so IMHO, my ignition switch shouldn't suffer from the problems a lot of others have (voltage drop, seizing up due to heat, failing to operate etc) and on re-reading your initial post, I was of the opinion originally that it had stayed in mesh when in fact it didn't get that far. This even further points to insufficient voltage causing slow engagement as it obviously had enough oomph to spin the starter motor but not enough to mesh the drive cog.
Incidentally, if this is a new starter, was the meshing distance between the end of the starter body to the end of the shaft measured when fitted? For some reason, they always seem to make an issue out of this in service manuals.

Alan S
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