Valve timing, injection start for the 1Z engine

Hello,

I'm experiencing a slight cold start problem with my car, and I have a few questions about it. It's not a major issue because I don't have to crank the engine for minutes before it starts; it just takes maybe 1-2 seconds longer than when it's warm. You can definitely tell that something is off.
Well, that's nothing new with the 1Z.
My initial suspicion was naturally the start of fuel injection.
So, I connected the VAG-COM and used the TDI-Graph to test the injection timing.
It's almost exactly at the target value, but it occasionally slightly exceeds the midpoint.
I check this every few thousand kilometers, and I can therefore say that it has been like this for some time now.
Now I'm also aware of the issues with the kilowatt screws and the problems that can arise from them.
So, I just checked the valve timing using a ruler and feeler gauges.
The locating pin fit perfectly into the opening, but the ruler for the camshaft did not.
Roughly estimating, I would need to rotate the camshaft by about 0.5 to 1 degrees for the ruler to fit properly.
Could this be my problem?
Do I need to worry about the crankshaft sprocket now, since it might have become misaligned?
If the crankshaft sprocket were to twist, then the camshaft and electronic spark timing (ESP) would also be misaligned. Surely, I should be able to detect this twisted ESP in the TDI graph?
Since the dynamic injection point is correct, it can only be a misalignment of the crankshaft, right?
Can a slightly misaligned north-west axis now negatively affect the starting behavior?
How can I remove the rear wheel without the original torque arm? Is there a trick to do it?
I noticed that the coating on some of the cam lobes is worn off. In these areas, you can see different metals. Should I be seriously concerned about this, or can I continue driving with it?

Hello golf3schrauber!

Okay, in your specific case, I would normally rule out the water pump (KW-Rad) for now, because according to your statement, the point at which the spraying starts hasn't changed during the last checks over several thousand kilometers .
Given the current temperatures, I would recommend checking all the glow plugs and verifying that the temperature sensor is providing reasonable readings.
The deviation in the northwest position sounds like sloppy work by the mechanic during the timing belt replacement, but it should practically have no effect on cold starting behavior.
Have you ever had the engine's compression checked? With your mileage, the compression could already be quite low due to wear and tear, which would negatively affect cold starting performance.
What is the mileage on those injectors? Poor fuel atomization at very low temperatures can also lead to starting problems (often accompanied by white and/or blue smoke shortly after startup).
However, the wear marks on the camshaft lobes don't look very good. Could you please take a recording of them and post it here?
Minor track marks are normal, but grooves or uneven wear patterns are not.


Regards,
Alex.

Hello,

Thank you for the answer.
The glow plugs are okay. I recently replaced a glow plug. There's also power going to them. I can measure the current flowing to the interior lights, and that's fine.
I replaced the injectors about 70,000 kilometers ago, so they should still be working relatively well. However, you can see a little bit of blue smoke shortly after a cold start.
I can't say much about the compression; I haven't checked that yet. However, the oil consumption is quite low, less than 100 ml for every 2000 km.
I'll take some pictures of the camshafts this weekend. These grinding marks are only visible on the outer tips of the lobes.

Hello,

This morning, we had -5°C here, and I have to say, I was really shocked when I started the car.
The engine started on the first crankshaft revolution. However, I need to mention that I increased the initial fuel injection amount by 2 points last night.
That would actually suggest that the compression isn't that bad, right? Or can you compensate for compression-related startup problems by adjusting the initial data size?
If the engine no longer had compression, would injecting more diesel fuel lead to a higher combustion chamber temperature?

Hello,

After the excellent cold start performance at -5°C yesterday, it was noticeably worse again this morning at 0°C.
I've noticed this effect before: the engine starts better in extremely cold temperatures than it does around 0°C.
"But now the difference has become even greater. I once read something about it."
"It's possible that internal wear is preventing the ESP from building up the necessary pressure quickly enough. Could this be my problem?"
Is it safe to adjust the initial amount upwards without any worries, all the way to the maximum limit? Or will that lead to other problems?
Originally, the value was set to the lowest setting.

We've encountered this problem several times before, and each time it was the central screw.
Loosen the torque wrench.
So, if you want to be sure, then check this!