T4 TDI Problems: Common Issues & Fixes

Hello,

I have a 1999 Volkswagen T4 with a 111 engine.

Now, regarding my problem:

The vehicle sometimes has power and sometimes it doesn't.

If there is no power output, the following symptoms may occur:

It smokes heavily when idling and a little bit while driving normally. It consumes a lot of fuel, about 13 liters per 100 kilometers for city driving under normal conditions. The turbo seems to only kick in above 3000 RPM.

If it's running normally, you will see the following:
After driving at full speed on the highway for a while, it will shut off after about 30km and won't start again; this is normal. After repeatedly trying to start it, it will eventually come back on. The engine starts as if there's air in the system, runs like a tractor, and then returns to normal.

According to the workshop, the LLM turbo and its valve need to be replaced. All filters have been renewed, the federbeginn (likely a specific setting or component) has been adjusted, and the timing belt has been changed.

Ah yes, I was able to improve the issue of running without power by disabling the exhaust gas recirculation system. The vehicle is completely original and has not been chipped or tuned.

Can anyone help me or has anyone experienced similar symptoms before?


Best regards.
Pierre.

What's the deal with your fuel vent?
It's a small rubber hose near the driver's side, where the T4 is jacked up (near the fuel tank).
If it's blocked, a large vacuum will form in the tank until the engine shuts off.
To rule out or narrow down the cause of the problem, try driving without the gas cap for a while.
Problem solved? Then look for the tube. If not, you should check for air bubbles in the supply line; the pump might be drawing in air somewhere.
Fuel sensor?