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-   -   suddenly starter motor wont engage (https://www.volvoforums.org.uk/showthread.php?t=291725)

aardvarkash10 Feb 13th, 2019 21:53

Quote:

Originally Posted by cheshired5 (Post 2495429)
Both.
Here is a solenoid being operated disconnected from any starter. No brushes present or needed :thumbs_up:
https://youtu.be/bTj_lVMmgX4

correct as far as it goes, but not complete.

The video shows the hold in winding only operating. The hold-in is insufficient in itself to pull the pinion into mesh, which is why the pull in winding exists.

To go even further, the current through the pull-in passes through the starter and allows the armature to rotate slowly. This assists the pinion mesh with the ring gear.

http://autosystempro.com/starter-con...it-components/

Laird Scooby Feb 13th, 2019 22:09

Quote:

Originally Posted by cheshired5 (Post 2495429)
Both.
Here is a solenoid being operated disconnected from any starter. No brushes present or needed :thumbs_up:
https://youtu.be/bTj_lVMmgX4

Totally different scenario in that to what we're talking about - the solenoid has been removed for testing and a permanent +12v feed has been croc-clipped onto the exciter wire. The earth leac is being touched on the other solenoid terminal - in this case the pull-in terminal or the main output terminal of the heavy current switching part of the solenoid - i.e. the feed to the motor.

Perfectly normal test in an auto-electrical workshop - not so easy when the starter is still on the car and you're trying to diagnose the reason for sudden failure.

cheshired5 Feb 13th, 2019 22:30

Quote:

Originally Posted by Laird Scooby (Post 2495449)
Totally different scenario in that to what we're talking about - the solenoid has been removed for testing and a permanent +12v feed has been croc-clipped onto the exciter wire. The earth leac is being touched on the other solenoid terminal - in this case the pull-in terminal or the main output terminal of the heavy current switching part of the solenoid - i.e. the feed to the motor.

Try this video then where @ 1min40 it clearly shows solenoid operation using the starter body as the ground. https://youtu.be/n-RzcsdFoRQ

Quote:

Originally Posted by aardvarkash10 (Post 2495441)
correct as far as it goes, but not complete.

The video shows the hold in winding only operating.

Hang on..... You've gone from definitively saying the solenoid is grounded through the brushes to conceding that this isn't necessarily the case.
You've also said that solenoids don't stick when they can but to be honest, I'm not here to debate.

We all maintain old cars with no assistance from professionals so whatever we're doing must be either correct or as near as..... Unless we're all fixing cars by blind luck. :)

Anyway, I'm out of the discussion. :thumbs_up:

sv70 Feb 13th, 2019 22:45

Brilliant guys a 3 way duelling banjos,right over the top of my head,but most entertaining,cheers.

Laird Scooby Feb 13th, 2019 23:02

Quote:

Originally Posted by sv70 (Post 2495459)
Brilliant guys a 3 way duelling banjos,right over the top of my head,but most entertaining,cheers.

Funny thing is, Ash and I were saying the same thing from two different angles and also picking up on bits the other hadn't said for whatever reason.

If you investigate how a pre-negaged starter motor operates, i'll let you draw your won conclusions but i'm confident you'll work out what's what! :thumbs_up:

aardvarkash10 Feb 13th, 2019 23:36

Quote:

Originally Posted by cheshired5 (Post 2495454)
Try this video then where @ 1min40 it clearly shows solenoid operation using the starter body as the ground. https://youtu.be/n-RzcsdFoRQ

*sigh* Yes, because the starter motor brushes are grounded through the armature and to the starter body. Take a look again at the circuit diagram that Dave posted. If it helps, trace the two solenoid circuits in two different colours - the paths are obvious and obviously different.

Quote:

Originally Posted by cheshired5 (Post 2495454)
Hang on..... You've gone from definitively saying the solenoid is grounded through the brushes to conceding that this isn't necessarily the case.
You've also said that solenoids don't stick when they can but to be honest, I'm not here to debate.

No, I said there are two circuits in the solendoid which have two different grounding points. See my point above.

Quote:

Originally Posted by cheshired5 (Post 2495454)
We all maintain old cars with no assistance from professionals so whatever we're doing must be either correct or as near as..... Unless we're all fixing cars by blind luck. :)

For some, it would seem that blind luck may well be the correct answer.:confused_smile:

Laird Scooby Feb 15th, 2019 10:00

Another forum member who has been following this thread has reminded me it might also be the Volvoguard system inhibiting the starter. However the fact it seemed slow the first time it nearly didn't start does tend to point towards brushes and/or a bad earth somewhere. ;) :D

bluebrickrick Jan 13th, 2020 23:33

Hi Dave & Ash, been out of circulation for a while, don't ask, involves lower end of a tibia, a bit broken off it and the rigmarole since :(

I've been bottom feeding on a 945 just about to hit the crusher and have been struggling to remove the ignition switch.

My current blue brick has developed an annoying fault of sometimes not having the starter operate, intermittent but annoying. hot wire between solenoid and battery terminal results in instant action so I thought I'd have a spare switch module in case I can't find a wiring break, plan A put in another switch, plan B hard wire a parallel wired switch on the dash with a new wire.

Unfortunately the donor is a way off and in a farmyard, I forgot my mirror on a stick and my restricted movement doesn't allow the usual contortions to view. I just could not see a way of separating the switch from the lock barrel and having had a search here can't find an idiots guide!

Unless there is a short cut it appears I either have to drill out the 3 screws holding the top steering shaft, take the little genny and angle grind the steel bracket on which they are fitted or resort to pyrotechnics.

Can you offer any alternative ?? The up side is that I have found a key that fits if it is the whole unit that has to be changed.

And that is without the blue fingered saga of removing the instrument panel bezel, yes I'm needing yet another Yakaza speedo......

Hope you're both keeping well and the wind isn't blowing your way Ash, from Oz - looks horrendous there :(

aardvarkash10 Jan 14th, 2020 00:06

I haven't ever removed the ignition barrel from a Volvo so can't comment on easiest method - generally the steering lock etc is manufactured with a hidden spring clip that secures the lock and the actual switchgear is a screw mount on the other end of the barrel.

Plan C - fit a relay in the solenoid circuit.

This is potentially easiest - you don't need to remove anything and it takes the high current loading presented by the solenoid off the ignition switch (and inhibitor switch if auto).

Ask if you need a diagram and instructions.

On the issue of wind and weather - bloody breezy here last week and I was sailing in the Hauraki Gulf on my brother's boat (26 foot Raven). Some hairy moments.

Meanwhile, this is what the Australians are sending us...

https://www.nzherald.co.nz/resizer/9...NMDBD67ZBQ.jpg

bluebrickrick Jan 14th, 2020 00:17

Thanks Ash, its a non turbo petrol, I suspect the switch hence my foray after a spare to at least figure out how to dismantle with minimum smoke emitted - unlike your photo - talk about sepia filters going out of fashion ;(

When I have been able to get a meter on it in fault mode it is nil rather than reduced voltage feed and no amount of steering wheel or dash clouting improves matters.

Given how long I was chasing that intermittent uncrimped 'hotwire' to the fuel pump, life 'aint long enough............

Cheers Rick


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