Car won't start (TDI AFN)

Okay, so...
In August, my Golf 3, manufactured in December 1997, with the AFN engine, experienced an automatic transmission failure (ATM) at 83,000 km due to a broken timing belt. Now, after 2,500 km, it has been starting poorly. My mechanic readjusted the injection pump's timing advance, but as a result, it now almost doesn't start at all. When the engine is cold, it stutters for 30 seconds before slowly starting. When the engine is warm, everything is fine. A re-check at the workshop revealed that the injection pump's timing advance is correct. Therefore, they tried to convince me that the injection pump is defective (but it was still starting before the adjustment???).
I suspected the glow plug system and checked it. My findings indicate that it's not glowing even when the engine is cold. When I disconnect the coolant temperature sensor, it does glow. I've already replaced the sensor with a new one, but the result is the same. When the power connector is plugged in, it doesn't glow; when it's unplugged, it does glow and the engine starts better (still not great, but it starts after about 4 seconds).
What should I do now? Is the control unit defective? All the glow plugs are fine, and everything from the glow plug relay to the glow plugs is working.

Another observation I've made is that the glow plug relay engages for a period of time when the engine is cold, and this happens when the engine speed exceeds 2800 RPM. You can at least hear it clicking. Is this normal?

Best regards,

Henning.

Hello,

Does the engine produce smoke when starting from a cold state, and if so, what color is it?


Another observation I've made is that the glow plug relay engages for a period of time when the engine is cold, and this happens when exceeding 2800 RPM. You can at least hear it clicking. Is this normal???

Yes!

There's also something called "troubleshooting" here. Please access it and review it.
It's not about pre-glowing. If you force a pre-glow, you're only masking the symptoms without addressing the underlying cause.
The easiest thing to do is to have the ESP settings checked again, but by a different workshop, just to make sure they weren't simply adjusted mechanically, like Haehnlein did in his extensive thread.

Okay, after a long time of playing, it's producing a gray/white smoke.

If it's not a problem with the glow plug system, then why isn't any electricity reaching the glow plugs at all, not even for a few seconds?

Hello,

Take a look at the outdoor thermometer. The reason it's not glowing is because it's too warm for that to happen. The TDI only starts to glow when it's below 9 degrees (or was it 5?), and yours doesn't glow, as you saw in the test with the disconnected sensor. At the current temperatures, it doesn't need to glow, so your problem is probably not related to the glow plug system.

In the early days of my TDI, I accidentally started the engine at -2 degrees Celsius without waiting for the indicator to go out, and it still worked. The engine started, although it ran a bit rough at first. So, something else must be broken in your case -> see troubleshooting.

Best regards,

Jan.

Hello,

White smoke indicates unburned diesel fuel. I would recommend having the ESP injection timing checked again by another workshop.
A compression test might also be helpful. Have the fuel injectors been checked yet?

I don't believe in preheating systems anymore!

I'm going to re-check the start time of the ESP and also perform a compression test.
I don't know if the fuel injectors are working properly; I had assumed they were fine with the new engine.
I've only experienced these problems since the workshop reset the start time for the charging process. I think they made a mistake while doing it (despite a second check at the same workshop).
I'll get back to you.

Fidel wrote:

I've also only experienced these problems since the workshop reset the start of the charging process. I think they were careless (despite a second check at the same workshop).

Hi,

That's exactly why (and it's also my suspicion) I would have the pump settings checked somewhere else now!

I had the same problem.

'When it was cold, my Golf 3 TDI (90 hp, manufactured in 1994) started very poorly.'
(The starter motor kept turning and turning). After a few seconds (sometimes longer),...
Occasionally, a puff of smoke would come out of the exhaust, and then the engine would sputter for a while.
It wasn't running smoothly at all for the first few seconds, but then it started working normally.

I then had all the glow plugs replaced at the workshop, which cost...
This was supposed to be the standard solution for this problem, but it was useless.
Whether the engine was warm or the outside temperature was warm, it started without any problems.
After some measurements, I discovered that the glow plugs had a connector attached to them.
No voltage was detected during the preheating process.

Solution at my place:
In the fuse box located under the steering wheel, you can see all sorts of things.
The fuse you're looking for is a 50A fuse located in the upper right corner, behind the relay labeled '21'.
hidden (you can actually only see it if you look at the fuse box from a certain angle).
Befestigung löst und ein bisschen dreht). This one was broken.
The whole thing had also quite confused me, because there was something in the engine compartment, below the...
In the middle of both windshield wipers, which is also where the glow plug control unit is located.
another backup is in place.