Astra G Diesel: Bleed VP44 Injection System

Hello everyone,

I'm having problems with my diesel system.
I have an Astra G, but the principle should be the same for most models.
I have a Y22DTR engine with a VP44 injection pump, where the PG16 engine control unit is permanently mounted on the pump. This type of pump was also used in Audi vehicles.
Since October, the engine suddenly stopped starting without a brief sputtering sound. After being idle for 6 hours, it wouldn't start at all. However, if I had already driven it, it would start normally afterward. There were no problems during operation.
At the beginning of December, the engine simply wouldn't start. I didn't want to keep cranking it, so I tried using starting fluid a few times. Then, I had it towed to the repair shop.
My acquaintance then replaced the diesel filter housing along with the filter and seals.
We replaced the seal on the pump; the Bosch part number is 1 460 225 083. This particular seal is known to be problematic.
Once everything was swapped out, the engine wouldn't start. Reading the error codes from the engine control unit revealed that it was faulty. I then removed it and replaced it with the original control unit from the first pump (which had an engine failure in 2021).
Then the workshop bled the engine again and took it for a test drive. After three days of inactivity, the engine still wouldn't start. It seems there are still problems with air in the diesel system.
I have already replaced the oil feed lines and swapped out the plastic T-pieces for brass ones.
The traverse seals were also replaced a year ago.
During the control unit replacement, I connected a hose to the crossbeam and blew into it with my mouth. There were no bubbles anywhere, and I couldn't feel any pressure loss.

Unfortunately, there is no pump in the tank. There is also no hand pump or transparent hoses where you could see air bubbles.

How can I check the system for leaks? My workshop and Opel are unable to help me with this issue.

Thank you in advance.

Hello,

Do you have a T-piece with an integrated temperature sensor (frost protection) installed on the diesel filter?

If so, I would review it.

Leak test: Install a transparent hose into the inlet of the VP44 pump, let the engine idle, and then check for air bubbles or foam in the transparent hose while inspecting the other hoses.

Best regards, Rainer.

Hi Rainer,

The "Knackfrosch" does not exist.
The fuel flows from the tank to the DFI (direct fuel injection) system. There is a preheating element integrated into the cap.
From Difi, it's on to the pump.
The hoses in front of and behind the Difi unit are quite rigid and short, and some are made of metal tubing.
I don't have any information yet about what diameter they are.
If I could find a hose somewhere, then I would still need some connectors with the right diameter.
For that, we would need to have a source.

My idea would be to pressurize the tank with 1 bar and then hope that some diesel leaks out somewhere. Is there a way to potentially detect this with UV light? It shouldn't be harmful to the engine, and the amount of dye needs to be sufficient so that it doesn't completely dissolve in the diesel and become invisible.

Quote:

My idea would be to pressurize the tank with 1 bar and then hope that some diesel leaks out somewhere.

Instead of applying vacuum on the outside, pressure is applied. With pitch, a leak seals itself using the other method, making the alternative method unsuitable for leak detection.



Hoses: Automotive parts retailers, hardware stores...

Are the injectors leaking?

scrat wrote:

I have got the engine running again. I removed the quick-connect coupling from the diesel return line, located behind the fuel filter, and connected it directly with a hose and a non-return valve. Okay, here's the translation: "Then, I cut the diesel line underneath the car. I plugged the line to measure pressure and took the supply line from the filter, checking it for vacuum (-0.5 bar). After 2 minutes, the vacuum disappeared. Then, I cut out the quick-release coupling under the car between the front and middle diesel lines and installed a non-return valve. Now, I no longer have any compressed air leaks." The engine now starts every time without any hesitation. However, it always runs roughly at the beginning and throws an error code. Error code P0149: Incorrect fuel injection timing/fuel injector pump. Using the OBD scanner, I clear the error code. When driving, the error code does not reappear.

Thank you for the feedback!