Passat 1.9 TDI Starting Problems - 1996

Hello everyone,

I'm having a problem with my Passat 1.9 TDI, manufactured in January 1996, with 230,000 km on the odometer. It starts very poorly when the temperature is below 5°C. The colder it is, the more I have to strain the battery to be able to start the engine. When it finally starts, the cylinders fire one after another, slowly, until the engine eventually runs normally.

Furthermore, I've noticed that after a few seconds of strong acceleration, it stops accelerating. It then simply maintains its current speed (approximately 140 km/h, depending on the temperature).

I have absolutely no idea what could be causing it.
I have already checked.
- Glow plugs (replaced, voltage is applied).
- Crankshaft bolt (inspected).
- Mass airflow sensor (replaced).
- Diesel filter (new)
- Air filter (new)

I hope someone here can help me!

Sure, here is the translation of the text from German to English:

'MFG gugi' translates to 'Best regards, gugi' or 'Sincerely, gugi'. It is a common German abbreviation for 'Mit freundlichen Grüßen', which means 'With kind regards'.

'Have the timing been checked? Is the fuel injection start timing set correctly? Have the injectors been replaced before? Is there air in the diesel system? Is the DFI (Diesel Particulate Filter) also sealed?'

Try using the search function and look for 'Haehnlein's mega cold start thread.' I think you'll find what you're looking for there!

'edit: Is your ESP (electronic stability program) sensor sealed properly at the driveshaft seal? That's one of the most common causes of air getting into the system!'

Hi,

I'm somewhat familiar with that effect; in my case, the fuel line was leaking, and the fuel was flowing back into the tank when the car was stationary.

Then you can play the organ - However: when I was driving, there wasn't much to notice, as the leakage was very slight; the problems were mainly visible in the adjustment of the injection system. And it wasn't related to the temperature, but only to the idle time.

I don't know if it could be the fuel line in your case, of course.

However: If there is a large amount of air entering the system, the first thing that happens is that it prevents the pressure needed for the injection adjustment, which causes a decrease in performance.

If you continue like this, you are severely damaging your ESP.

Could it also be related to the timing belt replacement I had done a few months ago?

How can I find out if my fuel system is leaking?

gugi wrote:

I had my timing belt replaced a few months ago, could that also be a possibility?

Yes, if the motor controller was subsequently misconfigured -> see above + technical articles.