T2 dead battery, won't jump start

[Lazy-Ferret]

Suz should have had an interview this morning, but when I go out to start the car, I find I have managed to run the battery flat on my T2 by leaving something switched on. I think to myself, "not a big problem, I will just start it from the second battery"....

No go, she turned over, but would not fire, and drained that one. Ok, I'll jump it off the T1. She still won't start, but the poor T1 has been standing, and the battery is pretty low already, so I start the T1, to allow it to charge both it's and the T2's batteries. Luckily the T1, has a hand throttle, so I could lift the RPM to about 3K, to really spin the alternator.

I gave it about 10 mins, and then tried to start the T2 again, but still no go.

Suz heads in to try and re-schedule her interview and make a cup of tea.

I decide to completely disconnect my battery, and leave the T1 charging that, while I come in here for a read for clues, as I am sure I have read other people having this issue before.

I wade through a few likely looking posts, and go back out to pull and check various fuses, that were mentioned as likely candidates, but all seemed OK. I reconnect the battery, and leave it still jumped to T1, and try to start her again, but she is still turning over, but not firing until the battery is flat again.

I leave it charging and came back into house again to do a bit more forum hunting, and came across this thread.

In this thread, Rusdat posted this very handy bit of information.

Well there was nothing wrong in the fuse box and the car started

I looked in the manual and found this in section GI-4:

"When failing to start the engine first-time using the key of
NATS, starts as follows:
(1) Turn ignition key to “OFF”.
(2) Wait approx. 5 seconds.
(3) Turn ignition key to “START” again while keeping the key
apart from any others on key-chain".

It worked waiting about 5-10 seconds. When i tried to jump start i am sure i waited more than 10 sec to let some current flow to the battery. Quite odd it did not start. When i tried tonight after recharging, i only tried 2 times for a good few seconds and nothing happened. When i came down the second time i turned the key, no start and then waited as described above and it started. Maybe a thing to remember. I am just wondering why it's not possible(it seems) to jump start a T2 TDI???

Thanks for your time and input guys

Lars

So, I went to my car and tried again. Still no fire... Took key off of key ring, there is only a couple of other things on there anyway, and tried again. Still nothing. So this time, I turned the ignition off for 5 seconds, turned to first position, waited a couple of seconds, into second position, again waited for glow light to go out, then to the start position....

Car started as she normally would.....

So... what is this all about?

 

[solarman216]

I have heard this before about not being able to jump start a TDi, all I can say to that is, I regularly start my off road motor this way cos I keep forgetting to disconnect the battery before leaving it for a few weeks, I think in your case Clive it is two things, 1 a dead battery still connected will take a lot of the power from the slave battery and whilst many times this may work on a petrol engine the diesel requires just that bit more grunt, 2 a dead battery stabbed with a slave can cause voltage variations which I think scramble the NATS system till the voltage stabilizes, Rick

 

[rustic]

I have heard this before about not being able to jump start a TDi, all I can say to that is, I regularly start my off road motor this way cos I keep forgetting to disconnect the battery before leaving it for a few weeks, I think in your case Clive it is two things, 1 a dead battery still connected will take a lot of the power from the slave battery and whilst many times this may work on a petrol engine the diesel requires just that bit more grunt, 2 a dead battery stabbed with a slave can cause voltage variations which I think scramble the NATS system till the voltage stabilizes, Rick

I agree, the jump leads are long, and thinner than what's on the car, so there will be a huge voltage drop on the main battery, with surges of power and drop out of voltages as the starter motor is not a clean electrical load, very inductive and a source of voltage spikes, that a normally charged battery will smooth out.

Caution... starting a vehicle this way, without a good charge on the main battery might produce voltage spikes which could damage sensitive electronic equipment. However, car electronics are actually quite tough, but what they don't like is reverse voltages.
A better solution is to make sure the main battery has good charge before attempting a jump start in this way.

 

[AlexD333]

Yup, when my battery was naffed we tried jumping with a master slave and leads from work, no joy, just not enough juice to get through.

As soon as I changed battery she fired right up :thumbs

 

[Paff]

When I started as a motor vehicle apprentice in 1976, somehow two good lengths of thick starter cable found it's way into my bag :augie

I bought four really heavy crock clips and now I have some serious heavy duty jump leads :thumb2

Difficult to bend about but I still have them to this day, better than these pretend jump leads you can buy today that melt when you use them :doh

 

[panelbeater]

my leads are 600ampx5mtr rated but my t2 with running fast would not jump my mates kia 4x4 as his battery was shot.it turned it over but not fast enough.i put it down to to long a lead but his battery was really shot.had to get new one,well rac did,cost him an arm and a leg,we were away in the middle of nowhere with vans and it was a sunday.rac could not sort it till mon afternoon as had a job getting the right battery,still its got a 5 year replace gte.

 

[rustic]

...better than these pretend jump leads you can buy today that melt when you use them :doh

Cheapo jump leads only clamp the inner core with a crimped slot, I had one set once that bent the core back over the insulation, and clamped both insulation and wire, that explained why it melted.

The other issue is, that only one side of the croc clip is actually connected, I normally mod them with additional wire to link both sides of the clamp, rather than rely on the spring for the clamp, which often over heats, and looses it's spring tension.

Some also use aluminium cores, which corrode after a couple of seasons...

Welding wire is probably the best, the thicker the better. 35mm2 would be good, but some cheapo ones are only 6mm2 cable no wonder they get warm sorry HOT !

 

[solarman216]

my leads ar 50 mm sq with good brass clamps, makes a difference, can start a truck with these, Rick

 

[Lazy-Ferret]

I have 2 sets of Jump leads, and both are very heavy, I learnt the hard way when I first started driving that you do not bother with the normal run of the mill stuff they sell. 1 set has very heavy croc clips each end, with copper inserts, The inserts have a flat copper braid running between them, and the main copper wire is welded to one side. The other set have an Anderson connector soldered to one end, and similar croc clips, but as you say, the wire is only welded to the copper jaws on one side. I have only really ever used them on petrol cars before though, so I think the Diesel is just too much.

I only use the cheap ones, when I want some reasonable cable for things like the caravan motor mover, or the wire up to my roof lights, cheaper than buying it by the metre.

I think you are right about the voltage spikes, as it did weird things like keep part locking the doors as you tried to start it at the beginning, until I left the other car to charge it for about 15mins.

It's still very weird though that even after giving it time to build up a charge, and trying to start it, it just turned over, but would not start, but with out waiting any longer than the time it took to take the key off the keyring, and turning the key with the small wait times, seemed to cure it.