1Z Messwertblock 13, was zeigt der an ? | Posts 16+

PS: The needle valve actuator has nothing to do with starting the engine!!!!

If everything stated above is actually 100% correct (including verifying the camshaft timing with a setting tool, not just reading dynamic data from the control unit), then there is very likely only one remaining possibility.

But always remember that nothing is impossible, and it's better to double-check everything before blindly trusting anything!

And what's left is the diesel pump, right?
The valve timing was actually checked 'manually,' meaning with a measuring tool.

We still haven't gotten around to disassembling the pump.
Or maybe have the nozzles checked beforehand...

Hello hello,

The old thread is being dug up, and it's been a long time since it was last active.
I still have the Golf, and I'm still having the same problem because back then, three workshops and my unfortunately lacking knowledge about TDI technology didn't help...

I was completely fed up, so I got a friend to help me lift the car and we took off the crankshaft pulley. That bolt was incredibly tight! But I didn't care; it had to come off.

Look: The nose on the crankshaft is broken off!!
Okay, I cleaned the mating surfaces (as planned), installed a new disc rotor, inserted a new bolt, and tightened it to 90 Nm with a 90-degree turn.

Then it started again: the same thing all over .

It won't start. It only starts after a long cranking period...
The TDI graph is performing as expected.

Can the start of the boosting process be manually adjusted? What do I need for that? Specifically, is there a pin or something on the pump itself?

Or does anyone else have any idea what this could be?
In winter conditions, the engine struggles to start (taking about 20 seconds), and then runs poorly for a few seconds. In summer, when it's warmer, it takes only about 3-4 seconds to start, and then runs smoothly immediately.

Okay, one more thing. The preheating relay! What does that look like? In my case, I think a normal working relay is installed. Because when it's preheating, the light comes on for only 1 second, then turns off, but immediately comes back on again...

Hello Mike,
Since you've already checked all the usual settings, the only thing that could be left is the fuel injection pump. This problem with the engine running for a very long time before starting occurs when the distributor head of the pump is defective and worn out. I had the same issue once on a Golf3 Variant with a 1Z engine. I removed the pump, had it rebuilt by Bosch Diesel Service including a new 11mm distributor head, then installed it and started the engine after the initial bleeding. After one revolution of the crankshaft, the engine started, and nothing has changed in the two years since, even at -15°C.
You could also try checking the injectors while they are removed from your fuel injection pump. If the engine starts but the injectors only begin to spray after a longer period of cranking, the pump is defective. However, just look and KEEP YOUR FINGERS AWAY, as the high injection pressures can cause diesel jets to penetrate the skin. Under no circumstances should you hold anything by hand during testing. It's safer to have the pump checked on a test bench.
Before proceeding, it's worth checking whether the problem still occurs with the starter motor solenoid removed, or if the engine starts slightly better in that configuration.

Before proceeding, it's necessary to check whether the problem still occurs with the extended starter motor solenoid, or if the engine starts slightly better in that configuration.


I've never heard of that before?! How can I test it? Where is the stop cock?


Thank you for your help.

Answer in the new topic: "Problems with starting behavior for 1Z engines for 1 year" https://community.dieselschrauber.org/en/viewtopic.php?p=75349#75349 under diesel engine technology.