VW Golf 2 Conversion Troubleshooting

Hello, I'm having a problem with the AFN engine in my Golf 2. It starts very poorly when it's warm. I've done some research, and it seems like many AFN engines have this issue. However, my problem seems relatively easy to solve. I noticed that the previous owner installed a coolant temperature sensor directly into the air intake. Now my question is, where are all the sensors located on the AFN engine? I haven't found a free space for one yet.

Thank you in advance for your answers.
Sincerely,
Max.

Hi.

I "told" (through MSG encoding) my Galaxy that it's an automatic, and since then, it's been starting up without any problems, even when warm.

Best regards,

I don't think the coolant temperature sensor is in the airflow path, because if it were, the cable would also have to be extended, and the hole in the water flange would have to be plugged. I'm more inclined to believe that the AFN had, or at least once had, air conditioning, because in that case, it would have a temperature switch (which looks quite similar to the coolant temperature sensor) in the airflow path.

Hi!

To the best of my knowledge, warm-start problems in engine generation are often caused by a starter motor speed that is too low.

Also Anlasser, Batterie, oder Kabel verschlissen. Contact problems.

As far as we know, this is supposed to prevent rough engine starts, but it only becomes effective above a certain coolant temperature.

"I've experienced something similar with my Golf. In winter, when the temperature was below -15°C, it would start immediately if it was warm, but usually it would be difficult to start if it was cold. This was simply due to the old battery, which is very difficult for ordinary people without a technical background to understand. However, this behavior is programmed into the engine control unit."

I would now, in this case, simply use a proper diagnostic system to read the engine coolant temperature from the engine control unit, as well as the engine speed during the starting process, when warm, and when cold.
I believe I recall that 300 RPM is required, but only above a certain coolant temperature.

Quote:

...in winter conditions, at temperatures below -15°C, it would start immediately if it was warm, but usually it started poorly. This was simply due to the old battery, which is very difficult to explain to ordinary people without a technical background.

I probably don't fully understand the nature of a battery yet. If it's old and it's very cold...?
As mentioned above, it is important to check the temperature sensors, as well as the valve timing.
hg
Herbert.

"Well, as an ordinary citizen without a technical background, I wouldn't exactly describe myself as an expert. Yes, there was/is an air conditioning system installed in the AFN, but it's more or less defunct, which could explain the temperature sensor issue."
I once measured the battery voltage during the starting process, and it didn't drop below 10V, so I think we can rule out the battery as a potential cause. This would then point to the typical starter motor problem common in AFN engines. However, as you mentioned, I will check the starting speed again before replacing it.

Thanks in advance for the tips!

"Use VCDS to recode the MSG module to enable automatic start. This will allow the starter motor to engage at a lower RPM, takes a few minutes, and costs 0.00 Euros."

Hi,
Okay, if I remember correctly, the AFN engine has an old-style distributor injection pump.
In these cases, I believe the following should be checked: 1. Starter speed. If that's okay, then check the compression. If the compression is okay, have the fuel injection pump checked, as well as the fuel injectors.


Normally, with this older technology, the problems are usually mechanical failures (assuming the temperature sensors are working correctly).

I recently had the fuel injection pump replaced on my Passat 1.9 TDI, and it cost me €300.
That would have been an AFN.
It has 290,000 kilometers on the odometer and starts very well, both when cold and when warm.

If you are interested, I can provide you with the company's address.

Greetings Julian

Hello.

Quote:

Normally, with this old technology, the problems are usually mechanical failures (assuming the temperature sensors are okay).

The fuel injection pump itself rarely fails to the extent that the vehicle won't start.
The injection start control can, at most, cause problems, which, although dangerous for the engine and having very unpleasant side effects, are irrelevant for the starting process.
Or, the ESP might be drawing in air through a worn-out pump shaft with a faulty seal, but at that point, you'd probably already notice that not only is air getting in, but fuel is also leaking out...

Having an injection pump overhauled solely due to starting difficulties is therefore very likely the best way to waste money.
It would be much more helpful to first determine why the car won't start.

Best regards, Rainer.

Yes, Rainer, that's probably true.
But if everything else is okay, then it might be worth considering a pump.

However, if warm engines fail to start, the problem is usually related to issues with compression (pistons, valves) or incorrect readings from temperature sensors.

That's my experience.

Since the AFN engine isn't really a highly complex piece of technology, I think it can be easily determined with the help of a few testing tools.

Greetings Julian

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

and specifically for starting problems:
Okay, I'm ready. Please provide the German text you want me to translate.