2004 TDI Polo Weird starting problem

[rg1642]

Hi all,
This one is irritating me like hell.
The car runs perfectly, starts ok nearly all the time and then for no apparent reason it will not start. It is like the battery is nearly dead. The dash lights come on dimly and the motor cranks really slow and then stops. Jump start from another vehicle and it works fine. You can switch it of after the jump start and it fires up again on it's own ok. Battery has 12.75 volts showing even when the motor wont start. Why is jumping it starting it when the battery is ok anyway? Am I earthing it on the other vehicle or something? This can happen a few times in a day, once a month or not for months and then whenever. :aargh4::aargh4::aargh4::aargh4:

Has anyone else had this?
Ta

[e6m6a6]

Are on the connections on the battery tight free of any dirt? it is advised every now then to take off the lead and go over them with a wire brush
Im no wiz on electronic, even simple stuff! but my clio used to have this kind of problem, it started but at a sluggish rate.
turned out it was just the battery starting to age alittle, still worked but just not having that kick behind it. I took mine to boro tyres and they did a full battery test, have alook for someone near you that do a free battery test, common this time off year

[Silvergrey]

My '04 1.2 petrol had a similar problem. It was tracked down to a faulty temperature sensor, so the air/fuel mixture was sometimes not correct at ignition.

[rg1642]

It was the battery all along. I dont know how it was doing it but a new battery has sorted it. I think there is an intermittent charging problem with the alternator that might have something to do with it but it seems to be ok now.
Thanks for the replys though.

[shafinm]

Thanks for the info you described the problem were having word for word with our polo 1.4 tdi 2004 .
will try a new battery and see what happens .

[rg1642]

New battery did the trick for my sons car in the end. Weird though not what I thought a duff battery would show up as. You live and learn. I'd check the fault codes though as I am sure it is not charging properly all the time.

[bluesprintman]

I have a Polo 2003 1.9 tdi Sport which has been great until three weeks ago. Now have similar problem to above. Following has happened three time now.
Driving along and dash lights start coming on. ABS, etc. Radio goes off, and finally power steering fails but engine keeps running.
Turn engine off and not enough power in battery to re start.
Happened twice and recovery man came out and test battery and alternator. Battery was 9V and alternator not charging,
I fitted brand new alternator (110 Amp) and Bosch battery. Thought everything was fine now.
Today (wek later) same thing happened again. Wife has fans etc going and within about 1 minute, all electrics fail (insufficient battery power). Finally undrivable due to power steering failure, even though engine running. Checked fuses etc all appear OK
Checked battery which was only reading 9.6V. Checked output directly on alternator and only reading 10.6V. I guess this should read 14V or thereabout.
Any idea anyone?

[rg1642]

My boys was just the battery in the end. there is a fault code up showing intermittant connection somewhere, cant remember what off the top of my head but there was a fix somewhere. Apparently the loom is too short and one of the wires breaks. Worth a google search. Sorry I cant remember where I saw it.

[bluesprintman]

Ok thats interesting as I did notice that the wire to the alternator are very short (and therefore tight). I measured the voltage from the postive cable from the alternator across the case of the alternator and only got 10.6 volts when I was expecting in the region of 14V.
Not sure how these alternators work and where the voltage regulator is. I assumed it is inside. What is the purpose fo the two wire plug?