Symptoms for a clogged diesel filter:

Hi, tinkerers,

I had the following problem this morning: -10°C outside temperature, fully fueled yesterday evening. The engine started well. After about 3 km driving through the village without any problems, I get onto the main road and the car no longer responds properly to the accelerator. Then, suddenly, the ASR/ESP light in the dashboard starts flashing. 'Well,' I think, 'it must be icy.' It was like driving on ice, but I couldn't accelerate because the ESP detected a wheel that was slipping.
Then, the ESP lamp suddenly started to light up constantly. The road, however, was not wet but dry.
My TDI is now only running at 50-60 km/h with Volgas, and it's also acting up.
I then drove directly to my workshop. Even when standing still, the ESP lamp was still glowing.
Then, the error memory from the ESP was read out. There it said: 'Error detected, please read the engine control unit.'
In the engine control unit, the error 'Injection start - control difference sporadic' was recorded.
The indicator light, however, did not blink.

Ultimately, the cause was a clogged or frozen diesel filter. 'That happens sometimes, as there is always some water in the diesel,' the mechanic said.

Personally, I had suspected a faulty speed sensor on the wheel. But things usually turn out differently than one expects...

Greetings

Eike

eike wrote:

Then, the error memory from the ESP was read out. There it said: "Error detected, please read the engine control unit." In the engine control unit, the error "Injection start - control difference sporadic" was recorded. The indicator light, however, did not blink. Ultimately, the cause was a clogged or frozen diesel filter. "That happens sometimes, as there is always some water in the diesel," the mechanic said.

Hi Eike

that could even be true [Sarcasm ON] although the information came from a garage {Sarcasm OFF}.

The starting pressure adjustment works by controlling the internal pressure of the pump, and a free-flowing nozzle is used to build up and maintain this pressure.
By the way, it also includes a free fueloptionto prevent the pressure from rising too much.

[Translating...]die sache mit der warnlampe kann ich verifizieren.

beim spielen mit 10-cent tuning hatt ich ein paar mal notlauf. da leuchtet dann die ASR-lampe und im ABS steht dann 'bitte motor auslesen'.
der meldet dann auch 'mengenstellwerk regeldifferenz'.

wenn ich das knallharte 10cent allerdings beim start schon eingeschaltet habe blinkt die glühwendel....

sehr mysteriöses vorgehen...

CU Gremlin

Hello Ulf,

ulf wrote:

[By the way, it also has a free-running fuelsystem, so that the pressure doesn't rise too much.

IMHO, there is a pressure relief valve in the pump, so nothing will happen. The fuel is then only pumped in a circular motion.

Hello, Rainer

Rainer K. wrote:

Hello Ulf, ulf wrote: [By the way, it also has a free-running fuelsystem, so that the pressure doesn't rise too much. IMHO, there is a pressure relief valve in the pump, so nothing will happen. The fuel is then only pumped in a closed loop.

Hi Rainer

in my yellow Bosch manual for VPs states, in essence, that the pressure control valve (which controls the internal circulation pump) and the overpressure relief valve (in the return outlet) are coordinated to maintain the internal pump pressure at the desired, speed-dependent level.

Therefore, the return pressure should also have an influence on the metering adjustment. . .

[Translating...]

Hallo Ulf,

ich denke eher, die Bohrung in der Rücklaufschraube sollte nur nicht zu groß sein, da sonst der notwendige Pumpeninnendruck nicht mehr erreicht werden kann.
Das Druckregelventil selbst sollte ein übliches Überdruckventil sein.
Ist aber nur mein Wissensstand, das heißt nicht, daß das korrekt ist.

Grüße, Rainer