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Discussion Starter #1
Hi,

Since I have bought my T4 van, the alternator is doing something strange.
When I first turn on the engine and leave it at idle speed, the alternator does not produces energy. The red LED on board is on, showing that the battery is not being charged. If I turn on the wipers, they move at a slower speed than when the alternator is charging the battery. If I turn on the lights I can see them clearly are not so bright as when the alternator is producing energy.
So this is happening after I just started the engine, and I did not accelerate at all. Leave the engine running at idle.

But as soon as I rev the engine a bit, the alternator starts working fine, charging the battery. It does not matter if I keep it accelerated or if I leave it at idle speed after that, the alternator still works OK until I switch off the engine and I start it again.

If I re-start the engine within few minutes the alternator still works OK.
But if I leave the engine off for longer than 1 hour (I really never timed this, is just an estimated time), than the alternator is not producing energy when start the engine at idle.

Until now I have never been bothered by this.
But recently I just bought and installed an alarm for the van. And this alarm has an option of "remote start".
I can use the pager from the alarm to turn on the engine from distance, without being inside the van. So every morning I can turn on the engine from inside the house, and 5 minutes later, when is warmed up (I can check the temperature from the pager also), I can go out and start driving.
That is the theory. Because in practice, the alarm needs to be connected to the alternator to sense when the engine has started up and is on.
But because my alternator has got gremlins in it, when I activate the "remote start sequence", it starts the engine OK, but because it is at idle and thus the alternator not producing energy (as in when the engine is OFF), after 5 seconds the alarm exits the "remote start sequence" believing that the engine did not start and in doing this it shuts off the engine.
So, because the alternator, my remote start only works for 5 seconds.

It is not from the brushes/regulator, because I just changed them with brand new ones a month ago. It did the same before as it does now.

Has anybody else got this kind of problem with the alternator ?

VW T4, 1994, 2.4D, Syncro, LWB.

Thanks.
 

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Mine does this too, it's not causing me any issues but if it's an early warning of a problem it'd be good to know.
 

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Discussion Starter #5
I do not believe this is a battery or alternator problem.
It is either a problem with the electronics (relay) under the dash board, bellow the steering wheel; or it has been designed like that by the Germans.

If you listen carefully when you FIRST rev the engine, there is a "CLICK" noise coming from under the steering wheel. Imediately after this click the alternator starts charging.
Now, if you leave the engine at idle, you do not hear another "CLICK" OFF anymore. That's why the alternator is still working.

That tells me it could have been designed like that. Or a problem under the dash.

I just wanted to be sure, before I rip apart the dash.
Up to now two other people have the same "problem".
Let's see if there are more.

I wonder if anybody has a manual for it, that can say something about this.
Or maybe there is a German on this forum who works on VW plant and can confirm this.

Regards
 

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i have a '95 2.4d aswell and this happens aswell. It also happens with my '82 golf gti cabby, so just assumed it was a VW design feature :confused:
Hope there's not a problem with either of them!
 

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Discussion Starter #9
is the click you can here the glowplug relay coming off
No, no way.

After I hear the glowplugs relay cliking off, I start the engine.
I do not know about other van engines, but mine is like this:
After the glowplugs are off I turn the key to start, and the engine starts instantly. I do not believe the engine is even doing a full turn, and it starts up. But if I turn the key to start, even 1 second before the glowplugs are off, then the engine turns about 10 times (or so), until it starts up.

After the engine started, I could leave it at idle speed for 10 minutes (I never left it longer, as it got warm enough), and the light for alternator NOT charging was still on. After that if I rev the engine for the first time, the light for alternator NOT charging goes off at the same time with the "CLICK".

Now I could believe that this was intended by the designers of the van.
Why?
Well this is not such a usefull feature here in UK.
But on the continent is (sometimes) vital, I could say.

20 years ago I was living in East of Europe, and I got my first car.
In the winter, there were nights with -(minus) 20 degrees celsius.
A brand new battery, in the first year would work ok, in the second year would still work ok, It can start your engine in the winter even after 3 or 4 days if you did not start the engine.
But in the third year of battery's life, it is so weak, that you have to start the engine daily, or the other day it might not have enough juice to start the engine.
In the fourth year you definitevly needed to buy a new battery. That if you were luky, if not you needed to buy a new battery in the third year.
At that time I was thinking to do something to my alternator's regulator so the alternator will not produce energy while I start the engine.
To produce energy, the alternator needs to take power from the engine. Mechanical power. But if the alternator is not producing energy, than it takes no power from the engine.
So, in the winter, when the engine oil is so cold that it changes the viscosity and becomes less fluid, the engine needs more power to pump it throgh the engine. Plus the cold has taken the juice out of the battery plus the alternator is trying to produce energy while you start the engine (so it takes mechanical power from the engine). All of these added together and you had a big chance the engine won't start, and the battery would die.

So I have found that to start the engine faster I needed to get my hand dirty, to unplug the excitation plug of the regulator for the alternator, to stop it taking mechanical energy from the engine while I start the engine. About 2 or 3 minutes after the engine started (leave the engine going for a while, or it could just stop because of the viscosity of the oil), I plugged it back, so the alternator would produce energy and charge the battery.

And consider that 20 years ago they did not have such materials to build such powerfull batteries as today, plus 20 years ago they also did not have such performants oils, that do not change the viscosity as much at lower temperatures, that's why I am inclined to believe this is in fact a "feature" not a fault.

So maybe the Germans have thought the same and built (some) of the cars and vans this way.
 
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