Weird starting/battery problem

[domiles1]

Its a T25 turbo diesel, 1.6, about 1986
I can charge the battery with a battery charger, then the van turns over well and starts fine. I drive a short distance and stop the van and it will not start again. Usually I get a very very sluggish turning over, indicating an extremely low battery, then on the next attempt I just get clicking!
The only way to get the van going again is to get it home and plug the mains in and charge the battery again - then it starts again fine. But I dont dare go anywhere in it!!
Is there a logical way I can check to find out whether its the battery at fault or any other part of the system?
(If it IS the battery, then it has developed the fault all of a sudden, it has always been a brilliant battery)

Thanks
Dom

[MattBW]

Sounds ilke the battery isn't being charged by the alternator to me but it could be a duff battery.

https://club8090.co.uk/wiki/VW ... r_checking" onclick="window.open(this.href);return false;

[richlaz]

Seeing as the battery charges on mains and then the engine starts fine, it could be the alternator

Check the output from your alternator (if you can get the engine running again )

[itchyfeet]

As you say you only drive a short distance after charging before it happens perhaps you have a bad connection with the wiring or a poor battery and it only just works after a charge but the battery gets a bit lower it does not work.

As said check the battery is charging first by measuring the voltage when running ( should be 13+V )
Also measure battery voltage after a few hours of charging to see what the resting voltage is, should be 12.5v ish for a good charged battery

if it all looks OK then start cleaning up connections.

Earth strap to gearbox, earth strap at battery to body, trigger spade connection on starter and main connection on starter are typical problems.

[jockrocks]

I've just had the same problem and I think it's the earth for the starter, if there is such a thing- connecting a jump lead to the chassis and then clipping the other end to the starter gets it going every time......

Is the starter earthed to the engine through the top bolt?

[itchyfeet]

Jockrocks, without hijacking domiles1's thread there is a earth strap to the gearbox at the front try cleaning this, also there is an earth connection between starter and solenoid, it's part of the starter but can fail, so if you connected the jumplead to the main part of the starter ( not the solenoid) then it's probably the gearbox strap.

[CovKid]

Theres also a small, almost hidden earth strap between solenoid and starter. These can rot and cause this problem. One day they work, next minute they don't until finally - nothing at all.

[itchyfeet]

also there is an earth connection between starter and solenoid.

[California Dreamin]

Ralph....positive copper braided feed between the solenoid and starter body....indeed, turns to dust.

Martin

[domiles1]

Charged up battery and started the van, expecting to get two starts out of it before it died, as described in my original post. But weirdly, the problem seems to have gone away and I was able to start the van more than 10 times easily, leaving it running for only 10 seconds each time for the last 8 attempts and the battery remained good! I cant understand it, unless it was something to do with the colder weather affecting a connection - will check them all anyway.
Checked alternator output: 14.37 volts. Noticed a blue witre hanging loose at the back of it and cant see where its supposed to be connected, I guess I'll have to remove alternator to get a proper look at the back.

[ghost123uk]

Noticed a blue wire hanging loose at the back of it and cant see where its supposed to be connected, I guess I'll have to remove alternator to get a proper look at the back.

I am not a Diesel owner, but I remember reading on here that blue wire is the feed for the (optional) rev counter on the Diesel engined vans. If you don't have a rev counter fitted it can just be insulated and safely fastened out of the way. If I am wrong about this someone will pop in and correct me

[richlaz]

14v from alternator is good... could have well been a connection problem. Did you check battery voltage after the numerous starts?

[domiles1]

Yes, battery is on 12.5 volts after numerous starts. The problem has mysteriously disappeared! I am confused!
Oh well, I'll drive it about and see what happens and at some point I'll check connections.
I assume the starter motor has to be removed in order to get access to the connections due to its position on the TD engine???

[nevill3]

I had an intermittent starting problem similar to yours, every now and a again I would either get a very slow turn over of the starter or just clicking. I cleaned up the earth cable, added an extra earth strap and checked all the usual things. The new earth strap appeared to cure it until the day before we were due to go to Cornwall for two weeks it failed to start at all. I even resorted to attaching a jump lead directly to the positive terminal on the starter from the battery. The starter motor had completely died over night!! When I removed it and stripped it I found that two of the carbon brushes were totally worn away and the other two were almost gone. My attempt at directly jumping the starter also burned a section of the commutator because the starter wasn't spinning.

If you can take off the starter and have a check of your brushes you may find your carbon brushes are worn too.

[domiles1]

I will check all my connections - but I'm still thinking it was/is a battery problem because it was always cured by an overnight charge-up.... and then it would die during the first start or two starts of the engine. Still confused really....!