Fuel Injection Start Problem: Target vs. Actual

The VP37 injection pump in my Golf 3's engine was replaced with a used one.

Since then, the AFN has been experiencing cold start problems: After an initial period of instability, there's a shaking phase, after which it runs smoothly.

The log shows that the starter motor speed is too low, and it is also likely that the glow plugs are not working properly.

Since the problem appeared after the pump was replaced, I have a question about the logged target and actual values for the fuel injection start timing.

The organ section is from line 16 to line 21.
The shaking phase lasts from line 22 to approximately line 39.

How can these unusual measured values in these phases be explained?

"Greetings, Klaus,"
and thank you for the answers.

What do you think the TDI Timing Checker is used for?

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Is the basic timing (TDI timing) correct?

Sorry, my mistake, I forgot to add: The TDI timing is practically unchanged from before: it's not on the ideal center line, but it's well within the tolerance range.
I initially just wanted to know if it's normal for the actual injection start value to be 0 during the organ phase, as it appears that it's not even being measured yet.

Best regards, Klaus.

Tip: It can only be measured if it is also injected.

No injection = no timing. No injection means there's air in the system, the starter motor speed is too low, or the pump isn't building up enough pressure.

Why don't you post a Screenshot of the TDI timing checker? Just press the "Print Screen" button on your keyboard and then paste it into a program like MSPaint.

Install a short piece of transparent tubing in the return line. It's possible that the used pump is drawing in air, which prevents the internal pressure of the pump from reaching the required level initially, rendering the pressure regulator ineffective.

You wouldn't be the first person to think it's cheaper to install a used one.