VW Bora ARL - rußt und ruckelt enorm unter Last | Posts 32+

Good evening everyone,

It's been a long time since I've had a chance to speak.

Inzwischen, the following has also been done to the car:

- Intake manifold inspected (Found to be completely in order.) Minimal deposits - approximately 1.5mm in diameter).

- The N75 solenoid valve was replaced.

- The boost pressure sensor has been replaced.

- All Ladeluftschläuche wurden zusammen mit den Dichtungen und Halteklammern ausgetauscht (Beachten Sie, dass jede Halteklammer am ARL eine andere Teilenummer hat, mit Ausnahme derjenigen, die am LLK befestigt sind).

- New OEM VW diesel filter (Due to starting problems after prolonged idling).

Problem: Everything remains essentially the same as before. After changing all the hoses, it feels "softer" in some ways, but it still produces black, gritty oil, jerks, and only has half the original power.

Today, I made some more recent log flights (See Appendix). The air mass seems to be suitable. The boost pressure seems to be holding better to the TARGET characteristic, but it keeps cutting out or remaining just below the TARGET.

We tested the VTG locking mechanism on the lifting platform again and it didn't seem to be holding properly. The VTG gymnastics went smoothly.

{OTHER_OPTIONS} wouldn't occur to me either. Everything else has been completely new - with approximately 90% original VW parts.

Should it be the turbo that's the problem, the car will be scrapped, and I'll get a new one.

If anyone notices something in the log entries that I may have missed, I am open to suggestions

Best regards, Timm

Hello,

The air mass value is also too low for a 2300 mbar boost pressure, so I suspect that the AGR valve is not closing or is opening due to incorrectly connected vacuum hoses, even though it should not. Also, also auch the throttle valve (parking valve) check, in normal operation, this valve is always completely open in the engine.

Best regards, Rainer

Hello Rainer,

Thank you for your feedback.

I have already disabled the AGR valve, so nothing should be able to pass through it anymore.

I re-blocked the suction valve earlier (disconnected and closed the vacuum hose) and went for a longer ride. Unfortunately, without success.

On a particularly steep road, he entered emergency mode at less than 75% load.

P1557 - Limit exceeded

Sounds like a sign of a stuck VTG (for whatever reason).

I exclude the possibility of incorrect hose connections. I can assure you of this. I had thoroughly labeled them before checking, and some of them only fit into their original position once.

Could a turbine wheel with excessive play be so strongly braked within the housing that it can draw in too little air? So far, I haven't encountered a case like this before.

Best regards
Timm

Herbert wrote:

The first, because it looks like there's a lot of air in the cylinder, even though the boost pressure is high.

If you can rule out errors on the intake side, then the exhaust side remains. If something is leaking, the filling won't fit properly either.

Quote:

I have already shut down the AGR valve, so nothing should be able to pass through anymore.

What about connecting the AGR (Exhaust Gas Recirculation) to the turbocharger? Exhaust manifold: Is it sealed properly and not warped or loose?

guste100 wrote:

Because it looks like there's a lot of air in the cylinder, even though the boost pressure is high. Herbert wrote: If you can rule out errors on the intake side, then the exhaust side remains. If something is sealed, the filling won't fit anymore.

I have already completely disassembled and checked the intake. From the beginning (intake behind the grill) to the fresh air side of the turbo, everything is clear. Even the air filter is new.

Then I will take a closer look at the alley side again. The muffler still sounds very good ("exhaust test"), and when I hold my hand against the muffler, I can also feel the pulsating exhaust pulses.

Quote:

What about connecting the AGR (Exhaust Gas Recirculation) to the turbocharger? Are the exhaust manifold seals tight and not warped or loose?

I haven't disconnected the connection directly from the manifold yet. But it has no leaks.

The exhaust pipe is definitely firmly screwed on. There are no soot stains around it. Therefore, I would not assume that the manifold is warped.


Can a camshaft wear so much that the valves don't open far enough to ensure reasonable cylinder filling?

Also, even the hydros could be affected. It all comes down to the same thing. Read!
https://www.yumpu.com/de/document/view/23049048/schwierige-diagnose-an-einem-tdi-motor-zawm

The cylinder head cover on the engine can be removed very quickly and easily.

Good morning everyone,

I wanted to get back in touch.

The problem with the jerking and sputtering has been resolved. The culprits were the hydraulic lifters. Two of them were completely broken, and three more were on the verge of breaking in the middle. Interestingly, there are very few traces visible on the camshaft itself.

Everything has been completely renewed (including the camshaft) and since then, it has been running perfectly.

The only downside is the cold start; if the car has been standing for more than 7 hours, it takes up to 12 seconds to start. This was already a problem, but it was resolved by replacing the diesel filter and the "Knackfrosch" (all OEM parts). As the next step, I will replace the metal clips on the hose with proper hose clamps, in the hope that this will finally solve the problem. The hoses themselves still look very good and new, with no signs of being porous or damaged.

I will send the photos later at

Thank you again to everyone for your numerous tips and assistance.

Greetings

Thank you for your feedback

Good evening everyone,

Due to personal circumstances, there was a delay, but as promised, here are the photos. I apologize for the quality. My mechanic is still using an older generation smartphone.

The engine has been flushed twice and has successfully completed approximately 9000 km since the repair.

Best regards,
Timm [/img]