help with solenoid valve

hi zusammen

First of all, I want to say that I actually used the search function, and I'm really at a loss now. I've been searching for this error for quite some time.

My Golf 3 1Z EZ 1.94 is no longer performing as well as it used to, and it's not reaching its previous top speed of approximately 200 km/h (according to the speedometer). Now, it's only reaching around 160-170 km/h. Sometimes, it also jerks quite violently, but only when I'm driving fast on the highway.

I've already been to a VW dealership, and they told me they could start replacing parts. However, they couldn't give me a precise estimate of what would be replaced and how much it would cost.
That's why I've been searching through this forum and have already tried a few things.
I replaced the LMM (likely referring to a mass airflow sensor), sealed the AGR valve (likely referring to an exhaust gas recirculation valve), replaced the injectors, and replaced the magnetic valve because I read that it's supposed to make a ticking sound. I think something on my car used to make a ticking sound before, and it doesn't anymore, but the new one isn't ticking either.
I also measured with a multimeter, and it shows approximately 12 volts on one cable and about 0.5 volts on the other. Is that correct? Furthermore, I read that the current comes in pulses, about 2 per second. Is that not the case with mine, or is it possible that the multimeter can't display it?

It would be really helpful if someone could assist me, rather than just telling me to use the search function.
If I've missed something while searching, it would be helpful if you could also show me where to find it.

"Thank you."

Hello Timo,

I won't direct you to any specific search terms, as you've likely already tried many things. However, without any error logs or diagnostic data, it's difficult for me to give you the right advice. My recommendation before replacing any more (expensive) parts would be to read the error codes from the vehicle's computer. You can either go to a VW dealership and contribute a small amount (between free and a maximum of 20€) towards their services, or you can purchase the basic kit here in our shop for 70€. With that kit, you can use the VAG-COM shareware software to read error codes and record data as many times as you like.

Both options are much cheaper than replacing the nozzle and solenoid valve, as you have already done (unless you had a donor vehicle).

If you're resistant to advice and want to continue troubleshooting, I would suggest checking the charge air cooler for leaks (oil mist escaping) and ensuring that the ESP (Exhaust Gas Recirculation) system is airtight and properly calibrated (which is not possible without a diagnostic tool).

Regarding the valve: There is a constant voltage of 11.5V applied to the valve, and it is being continuously controlled. Consequently, the control unit is attempting to build up more boost pressure. Whether this is normal or not depends on the specific control unit and the time of the measurement, and it cannot be stated definitively (since none of us will know every control unit and its behavior). Some ECUs adjust the voltage in idle mode depending on the ambient pressure, while others do not, and still others switch it off with a delay in idle mode.

Best regards.
Guste.

Okay, thanks. I'll stop by Volkswagen and take a look.
I have checked the air vent line and found nothing. The pump is actually drawing in air, or is it normal for small air bubbles to occasionally appear in the return flow when the system is running and stationary?
Furthermore, today I did a test run with the solenoid valve disconnected, meaning I only removed the power cables, because I thought that if it wasn't working, something would happen.
"But nothing has changed, it's all the same – acceleration, final speed, etc. The only difference is that it no longer suddenly starts to jerk."
Perhaps it was just a coincidence, because the shaking isn't always the same length or intensity.

If nothing has changed, there's likely a problem with the boost pressure regulation.

The fact that the thing is still running is thanks to the old wastegate turbocharger, which produces 0.6 bar of boost pressure without any input from the engine control unit. A VTG loader will show 0 bar if something is not working correctly.

It's possible that your engine control unit (ECU) is so tolerant that it doesn't go into limp mode.

However, what is currently incorrect unfortunately cannot be determined without logs and is practically impossible to diagnose remotely.

A new wastegate valve isn't making any rattling or ticking noises, but you can feel it vibrating when you touch it while the engine is running. Are you sure all the colored hoses are connected correctly and securely to the valve with clamps? Are the red and blue hoses still securely attached to the turbo and the wastegate?


m;

I just checked the hoses. The red hose is located above the power connection and leads to the turbo. The black hose is located below and connects to the intake hose. The blue hose is located on the side and leads to a control box.
"The hoses have always been connected like this. I have a repair manual, and in that, the hoses are connected differently."
black, located above the power outlet.
blue, on the side.
red below
"But that can't be right, because I've already tried that, and then I experienced an immediate loss of power while accelerating in 3rd gear at 100 km/h."
I once felt the solenoid valve while the engine was running, and it was working.
You can also hear the ticking very faintly.

Hi,

Here are a few ideas based on my 10 years of experience as a TDI driver (A3 with 90 hp engine, code: AGR, turbocharger with wastegate, and 388,000 km).

- one of the worst mistakes I made: a broken pin in the connector of the mass airflow sensor (MAF sensor). I replaced it several times, but there was no change. Then, by chance, I found it, soldered it, and it worked fine.

- next potential problem: water in the engine control unit - this can cause a rough engine running and reduced power... MSG opened, dried, closed, and wrapped with duct tape around the plug connector.

- I replace the N75 valve approximately every 3 years; it doesn't last longer than that for me. You might also want to verschandeln the wastegate valve occasionally, as the linkage tends to corrode and seize.

- Depending on the quality of the fuel, diesel filters may not last longer than 60,000 km.


I hope you don't have to invest too much money; often, it's the small things that cause big problems.

Let me know how it turned out.

Best regards, wolf.

hello
and thank you for your ideas.
Because I was traveling for work, I only managed to get the error codes read out at the VW service center today.
"And there's nothing to see," I was told, "so your car is in excellent condition."
It's kind of like that, but not exactly, and that's why I got a boost pressure gauge.
"I connected this using a T-connector to the black pressure hose, which runs indirectly to the control unit. And my highest measured boost pressure is around 0.85 to 0.9 bar, which I believe is what it should be."
Could it possibly be due to a faulty needle lift mechanism?