Starting Problems & White Smoke - VW 1Z Engine

Hello everyone!

'For about a week, I've been having intermittent starting problems. But now, it almost doesn't start at all. If I leave it sitting for more than 12 hours, it won't start (only with a jump start). Then it smokes white for a short time, and everything seems okay. However, while driving, it often doesn't respond to the accelerator. It initially smokes white, then gray, and after I press the clutch and give it some gas, it starts working again. The more the engine warms up, the more frequently these issues occur. The diagnostic scan showed an error related to fuel injection. In my opinion, either the crankshaft pulley is loose again (I replaced it only 15,000 km ago), or there's something wrong with the fuel injection pump.'
What do you think about it?
Sure, here is the translation of the text from German to English:

'Best regards,
W'

Hi.

I would also guess it's related to a sprocket or a pump.
Considering the rate of deterioration, it's more likely to be the sprocket, as those are, in my opinion, the "classic" symptoms .

Could it also be due to leaky or malfunctioning fuel injectors?

When left standing for a long time, diesel fuel continues to drip, and at high temperatures, the diesel becomes even thinner, which can cause too much diesel to enter the cylinder.

Hello Dirk,

Yes, he might be able to smoke then, but ideally, it should ignite properly instead of just rolling with the smoke.

Best regards, Rainer.

Evening!
First of all, thank you very much for your quick responses!
Today, I took a closer look at the timing belt and pulleys and couldn't find any defects. I had to tighten the timing belt slightly, but the pulleys were securely fastened.
Perhaps Dirk is right with his assumption. It would explain the starting difficulties and the smoking during load changes. But how can I identify faulty fuel injectors (without an oscilloscope)? Do you have any tips for me?

Best regards, W.

Hello NVE,

You can't detect faulty fuel injectors with an oscilloscope, except perhaps a defective needle lift sensor. The only way to check fuel injectors is to remove them and have them inspected at a local Bosch service center.
I personally suspect the problem lies elsewhere than the fuel injectors; it sounds like a combination of several issues. There should be something in the error database to help check the needle lift sensor.
It should also start easily in cold conditions, even with a faulty needle valve lifter.
I'd like to check something.
- Fuel injection adjustment via diagnostic device, cable/connector for the fuel injection adjuster and needle lift sensor.
- Faulty glow plugs / Preheating system OK.
- Is the head gasket okay? What is the coolant level in the coolant reservoir?
- Air bubble in the fuel line leading to the fuel injection pump if the car has been sitting for a long time (bubble longer than 1 cm)?

Best regards, Rainer.

Sure, here's the translation:

'Hi Rainer!'

Okay, I think the head gasket is probably fine; otherwise, he would have been constantly losing coolant, and the coolant and oil levels are correct. The glow plugs are probably okay too (aside from the fact that he doesn't use them anyway). I read the error codes using a diagnostic tool through the Touring Club: Error 550 indicates a fuel injection timing difference!
The issue with air in the fuel line is real; the bubble, or rather the bubbles, were larger than 1 cm.
Sure, here is the translation of the text from German to English:

'Best regards,
W'

Okay, that's something. It's possible that air is getting into your ESP system if your car sits for a long time.
I'm not sure whether the injection start control system will report an error with a partially air-filled ESP (Exhaust Gas Recirculation system), but it would be helpful to me, considering that the fuel injector is moved hydraulically by fuel.
Have you checked the fuel hoses on the diesel filter, and especially the two O-rings on the fuel return valve at the top of the diesel filter? Is the diesel filter screwed on at the bottom?

Best regards, Rainer.

Okay, so I've now disconnected the fuel supply and filled it from a separate container. There were no air bubbles visible before and during starting, but there are now. And it seems like the bubbles are coming from the fuel injection pump!

'When the engine is running, I occasionally see some air bubbles moving through the hose. The engine seems to be running fine otherwise.'

Ich bin mit meinem T3 (1Z-Motor) mal liegengeblieben und bin bei der Fehlersuche fast verzweifelt. Der Motor sprang immer wieder an, ging dann aber nach einer Weile wieder aus. Dabei spuckte er dermassen weissen Rauch aus, dass ich dachte der hätte ne Wassereinspritzung. Als Erstes dachte ich dann natürlich an Wasser im Spritfiler, aber das wars nicht. Ausserdem liefen dicke Luftblasen von der ESP in den Kraftstoffilter. Es stellte sich raus, dass ein Stück Dichtung die Kraftstoffzufuhr am Filtereinlass verstopft hatte. Wenn die ESP nicht förderte - also der Motor aus war - lief Sprit nach, und der Motor sprang hinterher wieder an. Lief der Motor aber, wurde der Unterdruck zwischen Verstopfung und ESP so stark, dass das Dichtungsstück dicht machte, nix mehr eingespritzt wurde und der Motor abstarb. Drei Mal darfst Du raten was mein StG dazu zu sagen hatte ---- Genau! '550' Bei Dir stelle ich mir das allerdings etwas anders vor. Deine Verstopfung scheint bei starkem Spritbedarf nicht weiter zu schliessen, d.h. wenn die ESP erst einmal fördert kriegt sie mit ach und krach noch das zusammen, was sie zur Einspritzung braucht. Mach Dir mal transparente Rücklaufschläuche auf die Düsen (Gibts zB. bei Conrad - 'Blueline' ) wenn da nichts ankommt, kommt auch nicht genug im Zylinder an. Stellst Du den Motor aber ab, zieht der Unterdruck im Kraftstoffsystem den Diesel wieder aus der ESP und der nächste Start wird wieder zum Kraftakt. Vielleicht liegt es bei Dir ja einfach an einem verdreckten Spritfilter oder der Tankentlüftung oder ... . CJust replace the entire fuel system!

Best regards, T3.

Hello everyone!

I just took my car to the Bosch service center, and they found the problem: The crankshaft pulley has slipped again, and it was misaligned by four teeth relative to the other components. No wonder nothing was working!
Thank you for your advice!

Sure, here is the translation of the text from German to English:

'Best regards,
W'