Starter motor - intermittent spin/disengage

[hardwick53]

A bit of advise please

I had the starter motor replaced as it was getting intermittent and eventually stopped spinning after a couple of taps on the solenoid.

The starter motor was actually replaced 5 years ago so I was disappointed the AA diagnosed this.

Anyway, it was changed and all well for a week or so. My local garage replaced the gearbox earth strap last week as it looked at bit corroded.

Van was sat for the whole of last week and would initially turn over but then disengage/spin-up after a second or two. Eventually stopped turning over. Gave the solenoid a couple of taps and it started. Its a new/recon starter from GSF.

I'm thinking there might be a high resistance in the grounding somewhere - but where as the earth strap has been replaced although in the wiki Aidan T recommends moving the earth strap to the starter motor itself....anyone done this?

Appreciate any advice

[California Dreamin]

Moving...or just adding...you can never have enough earth straps, so you don't necessarily 'replace' the existing one.
There should also be a longish 'copper' braided strap in the engine bay going between the coil bracket and top of engine.
Obviously, the other 'important' earth in the one on the battery...all must be pristine.
Yes I've got an additional strap on the starter to chassis offside.

Martin

[kevtherev]

I would be renewing some cabling if I could.
The live circuit also suffers with corrosion.
I had a troublesome starter, turned out to be the cable connector, looked ok but when the connector was removed it was just green dust.

[hardwick53]

Thanks for your replies.
I just popped into my local garage who are VW enthusiasts and I now have a couple of pointers to check out.
1. to prove/disprove the earth ground strap - use jump lead from negative terminal on starter to good ground or - batt terminal
2. check the condition of the spade crimp connection inside the rubber boot on the starter solenoid. as at one point the SM didn't turn or even click
3. check getting 12V on this crimp when ignition turned as could be the rotary contact unit connected to the ignition or crimp connection or damaged cable from front to back.
4. using a multimeter on DC volts, put the black probe on the + of the SM and the red probe on the + of the battery. This should ideally read 0V as you are trying to read any potential difference between the two points i.e. volt drop which could be down to deteriorated cable with high resistance, corroded terminals etc
So plenty to check
Thanks again for the replies. I will post the solution hopefully...

[hardwick53]

Point 4 - the volt drop measurement ideally needs to be done while someone else tries to start it i.e. when engine cold so the greatest current draw. Will have to see if my multimeter will be quick enough to read for the brief moment trying to start

[hardwick53]

It turns out to be a badly corroded spade crimp and less than tight fit onto the ignition switch terminal on the starter solenoid. I think this was the fault all along and didn't need the starter motor replacing. Just my luck!

[kevtherev]

Hmm I don't think luck came into it.
A search here would have flagged connectors and cables, do the cheap/easy things first.
I think a lesson learned is more like it.

[CovKid]

Unfortunately WAY too many perfectly good starters get exchanged because either the fault isn't the starter at all or because the fault is relatively minor (loose spade connector, rotted braid from solenoid to motor, worn brushes or even a duff solenoid). All can be fixed/resolved at home.

Come to think of it, of the hundreds of starters I've had cause to examine for faults, only ONE proved beyond repair and only because the starter body had rusted through. Never had a worn bearing in one either which is surprising.

I suspect many 'rebuilt' starters cost less than £10 to sort, and most of it spent on degreasing and repainting the body so it looks vaguely new.

[hardwick53]

kevtherev - if you know and have experience of these sort of faults, the time and tools to get into tight spaces then yes you could kick yourself. You may have much more knowledge and experience than most. Many posts don't provide the end solution which I wanted to post for the next person who is searching for ideas. Maybe one day I will have your level of knowledge and experience of these vehicles that I can be a supportive as you.

Covkid - I totally agree. Its so easy for the professionals to blame the unit and do a swap, yes they get more monetary value from it which is always an incentive and so many mechanics/fitters take an easy lazy route instead. i.e. replace the starter motor and don't check the looseness of the crimp connections to the spade terminal which he would then have seen the corroded copper.

Thanks and I hope this helps others.

[kevtherev]

kevtherev - if you know and have experience of these sort of faults, the time and tools to get into tight spaces then yes you could kick yourself. You may have much more knowledge and experience than most. Many posts don't provide the end solution which I wanted to post for the next person who is searching for ideas. Maybe one day I will have your level of knowledge and experience of these vehicles that I can be a supportive as you.

Covkid - I totally agree. Its so easy for the professionals to blame the unit and do a swap, yes they get more monetary value from it which is always an incentive and so many mechanics/fitters take an easy lazy route instead. i.e. replace the starter motor and don't check the looseness of the crimp connections to the spade terminal which he would then have seen the corroded copper.

Thanks and I hope this helps others.

Wait.
I'm sorry if my post came over as pedantic chap, it wasn't meant like that.
..knowledge and experience?, no I won't have that.
It is just common sense to eliminate all the cheap and easy fixes first isn't it, these checks can be done by the owner.
I and others are here to point out those checks, because owners tend to assume the worst. (like breakdown service recovery employees)

Drive safe

[what2do]

In response to kev's mention of 'assume the worse', I'm a shocker at assuming this/that/the other won't be at fault, therefore I hunt aimlessly for a fault where there is none. I'm cursed with it but having Itchyfeet nearby with his 'have you checked this' is a godsend.

One of my first problems with the van turned out to be the trigger wire crimp. I was on the way to have log fitted (Cowboys, ought to be shot) when it happened and they poked around with their meter and said I needed a new alternator!!!

[CovKid]

Few "old school" proper mechanics left. Modern ones only understand fault lights and they fit complete units without contemplating actually pinpointing the fault. I started doing rotation clutch replacements 30 years ago because that was how I was taught. Complete clutch fitted then the next time just the clutch plate if the rest is good. Still works for me but no garage does that these days. It doesn't help when you get some owners who answer technical questions with nothing more than a link to a new part - makes my blood boil.