Starter motor lesson required...

[The Bishop]

About a week ago (during the cold snap) I went to start the van, it turned about 3 times and stopped. The just a click from the solenoid.

At first I thought it was a flat battery but it wouldn't jump start from another vehicle. Put battery on charge which has 13.5v across the terminals and still just a click from the solenoid.

I've cleaned the terminals but still just a click.

Have removed the starter and solenoid, what next?
What are the relevant terminals on the solenoid? I have a thick red wire on a ring that goes on the back stud, then a thick black one. To the side of the solenoid is a thiner red wire, is this the trigger for the starter?
How is it earthed? Just through the connection to the gearbox?

What do I check next? How can I test the solenoid and starter?

[itchyfeet]

Thick wire on m8 ring is connected direct to batt be careful, another goes on to the alternator
there should be a red/black trigger wire that is thinner but still quite thick, its on a spade, try cleaning them to see colours properly
earth via gearbox, check strap on front of earbox bracket to body

[Jim San]

I'd whip it to the nearest trusty Auto-electricians.
They can run a simple test (I dont know if its just a case of putting 12v straight accross the solenoid).

If its sherafted they can either exchange or repair/recon.

I used to work at one in shropshire (in stores, 30 years ago) and the sparks would clamp it to a test bench and fire it up. They would use lengths of timber to press against the pinions to test under load.

[itchyfeet]

Can't test a wbx starter out of the gearbox, it only has one bearing, other is in gearbox, probably just need to clean contacts but could be a rotten wire or ignition switch failure as well as starter failure

[itchyfeet]

Pics stolen from somebody in here..

Shows main 12v batt stud and spade for trigger wire

[The Bishop]

Thick wire on m8 ring is connected direct to batt be careful

I've identified that at both the starter and battery end, so is that permanently live? And there's no fuse? If I put a meter between that wire and the gear box I should have my 13.5volts?

earth via gearbox, check strap on front of earbox bracket to body

Ahh so I need to check that "check strap"

[nevill3]

A quick test to help identify a poor earth problem is to use a good quality jump lead and connect it from the engine/alternator bracket to a clean solid bit of body work/chassis. If the starter works then you know that the earth strap is dodgy. My starter motor was totally goosed a couple of years ago, a couple of the carbon brushes had worn away.

A really good video showing how to strip the starter motor yourself to check it is here http://www.dubforce.net/forums/index.ph ... opic=23917

[itchyfeet]

Thick wire on m8 ring is connected direct to batt be careful

I've identified that at both the starter and battery end, so is that permanently live? And there's no fuse? If I put a meter between that wire and the gear box I should have my 13.5volts?

Yes if engine is running otherwise probably 12.5v ish

but volts is half the story, you can measure volts with a tiny current of a voltmeter and it will tell you its there, try pulling 000's of amps to a starter and a bad connection will mean the volts drop and so does the current.

volts loss = current x resistance, small multimeter test current sees no volt drop, big starter current sees lots.

no fuse on main cable batt to starter
no fuse on trigger wire cable
no fuse batt to alternator
while we are at it...
no fuse on ignition positive to engine bay coil etc
no fuse to engine bay heater circuits


most common fault is the trigger wire connection corroded or the faston/spade/lugar is corroded where it crimps to the cable, clean it up first

clean up main terminal (disconnect batt first)
clean earth strap to gearbox
clean up batt terminals

[AdrianC]

Thick wire on m8 ring is connected direct to batt be careful

I've identified that at both the starter and battery end, so is that permanently live? And there's no fuse? If I put a meter between that wire and the gear box I should have my 13.5volts?

Yes. There's no fuse, because it'd have to be huge - the starter can pull several hundred amps, easily. The alternator can output up to 90A.

So you're checking you've got +12v, but you're not checking how MUCH electricity the connection can deliver. Voltage is pressure, current is flow. Think about a hosepipe - stick your finger over the end to spray it at somebody, you get more pressure, but less flow. Take your finger off, and you might only actually be getting a dribble of water, when you want a good flow. Unkink the pipe, you get full flow.

earth via gearbox, check strap on front of earbox bracket to body

Ahh so I need to check that "check strap"

Yep. A circuit needs to be circular, right? There's two circuits needed to make the starter work. The big fat +12v to the big terminal, and a small +12v to the small terminal. The big one is perma-live, the small one is switched by turning the key. BOTH have to return to the battery, which they do via the engine/gearbox housing, main earth strap to body, through the body, to the battery -ve strap and terminal. Quick way to rule that out is to put a jump lead between something solid on the engine and something solid on the body or, preferably, the battery -ve.

You've clearly got +12v coming in to the starter, and some electrickery getting back to the battery, because the solenoid is clicking. But there's clearly not enough electricity able to flow through to make the starter actually spin. That might be because there's insufficient able to get in (dodgy +ve), insufficient able to get out (dodgy -ve), or it might be because the starter needs more than it should due to internal knackeredness of some flavour.

[The Bishop]

Thanks, looks very thorough.

I will get out there again as soon as I can and run through that list and hopefully that will solve the problem.

Thanks again for the education.

[The Bishop]

Well cleaned everything and put it back and no change. In fact I am not convinced the solenoid is clicking which would suggest it is knackered.

WLC sent me some notes so I will work my way through those.

[itchyfeet]

Ideally need to determine if its wiring or starter.
so it needs some confidence and care but you can briefly short the trigger terminal to the main bolt with a suitabe sized piece of metal, taking care not to touch anything earth.

another safer method is to make up a short lead with an m8 ring on one end, stripped the other and attch to the stud with main cable ( disconnect batt when you fit it) insulate the other stripped end temporarily
then another short lead with a spade terminal on one end, stripped the otyer and connect to the trigger terminal

Reconnect batt then remove the temporary insulation from the stud lead and briefly touch it to the trigger lead.

if you make the leads just long enough you can do this from the engine bay or wheelarch, 1.5mm2 is ok as its short and temporary

both methods provide 12v to the trigger terminal, as happens when you turn rhe ignition key but this eliminates the ignition switch and wiring, if it turns over starter is fine, if not it's probably at fault (assuming earths are ok)

one more thing, whats your battery voltage?

[The Bishop]

The trigger wire lights a bulb when the key is turned so wiring from the switch to the solenoid is ok.
If i "jump" power to the solenoid it clicks but nothing more.
The earth strap from the gearbox is good and strong and I've cleaned it today.

So my conclusion is that either the solenoid isn't working or the starter isn't working.

[itchyfeet]

The trigger wire lights a bulb when the key is turned so wiring from the switch to the solenoid is ok.
If i "jump" power to the solenoid it clicks but nothing more.
The earth strap from the gearbox is good and strong and I've cleaned it today.

So my conclusion is that either the solenoid isn't working or the starter isn't working.

Lighting a bulb is not the same as firing a solenoid, the solenoid will pull much more power but as you have jumped power direct to solenoid and it just clicks and earth strap is good, then I'd agree starter (assuming batt is good)

batt voltage, what is it?

can usually find a local place to rebuild but get a quote first,

somebody on here recently was billed £180 for a rebuild, he ended up refusing to pay, leaving it and getting a second hand one.

[California Dreamin]

My thoughts..
Copper braided wire..solenoid to starter body, has all but turned to dust.
Carbon brushes (internal to commutator) have worn very low.
Main solenoid internal contacts are badly eroded (the contacts that allow the current across and into the starter body).

May also be worth replacing the oilite bush in the bell housing whilst you are repairing the starter (cost under £3.00)

Martin