Pump Nozzle BMW 23: High Values

Hi there.

I drive a Volkswagen Golf 4 Variant TDI with an AJM engine.
Seit ca. 3-4 Wochen macht der Motor Probleme in dem der MWB 23 weit über die Grenze von 100 bei PD Element 1 u. 4 und so ca. 85- 100 bei PD Element 2-3. MWB 13 ist unauffällig, wenn man die Werte gegen einander aufrechnet komme ich auf 0,15.Die Elemente wurden vor ca. 1,5 Jahren überholt und sind wegen diesem Problem jetzt nochmal zerlegt und überprüft worden vom Überholer. Leider hat er außer beim PD Element 3 keine Probleme gefunden. Dieses hatte gegenüber der 3 anderen schlechtere Werte und wurde auf die anderen die i.o. sind angepasst. Den LUnfortunately, I cannot translate the provided text because it appears to be incomplete or contains only a fragment ("eitungs-"). Please provide the full text for an accurate translation.
I replaced the PD injector elements in the cylinder head, as well as the fuel pump. Unfortunately, there was no improvement. The engine has full compression of 29-30 bar. The turbocharger is delivering its values and responds immediately. The variable geometry turbo (VTG) is operating smoothly, and the control system is working correctly. I checked this with VCDS. The engine was completely overhauled at 308,000 km. The clutch is from the 131 hp ASZ engine because the AJM clutch and dual-mass flywheel (DMF) are not particularly durable. The engine has no chip tuning. The rebuilder suspects a grounding problem with the engine control unit (ECU) or the PD injector elements. According to the Elsa wiring diagram, the PD injector elements should have their ground connection directly from the ECU. I find this hard to believe, as quite a few amps are flowing through that connection. Does anyone know if there is a dedicated ground wire for the PD injector elements in the engine compartment, or where I should be looking? Elsa is not very helpful in this regard.

Regards,


Andre.

Hello,

Spontaneously: How old is the diesel filter?
Pressure on the tandem pump is OK - was this pump new?
Is the fuel pump in the tank providing enough fuel?

SG.

I replace the diesel filter every 20,000 km; I installed the current one about 2 weeks ago. With the old tandem pump, I couldn't measure the pressure because the pressure gauge was borrowed from my VW dealer. Unfortunately, I don't have a fuel pump yet. I'm still driving one of the early Golf 4 TDI models without a fuel pump. The suction power is solely provided by the tandem pump.

Regards,


André.

Plus or minus 100 in the MWB 23?

Unfortunately, the pressure is too high. If it were lower, the middle O-ring would leak at the PD element. I removed the elements last week to send them for overhaul. Everything is okay in the cylinder head. The camshaft, rocker arm shafts, and the PD element seats in the cylinder head are all fine.

Regards,


André.

High negative values in this mass airflow sensor reading indicate a fuel shortage. This is especially true if the issue is present across all injectors. In this case, the sealing ring in the middle is likely not the primary problem, but rather one of several possible causes. However, it would be a prime suspect if the issue were limited to a single injector.

You have very high positive values, which unfortunately means: the PDE is scrap, and it's internally blocked. No one likes to hear that, especially not the people who are supposed to process it.
You might want to consider using a "Bosch replacement injector in its original, sealed packaging" as a solution. Ultimately, it's a matter of personal preference: do you want to save money, or do you want to avoid hassle and potential problems? Also, you can't repeatedly remove and reinstall the PDE (high-pressure pump) because the six-point thread of the clamping nut isn't designed to withstand that kind of repeated stress.

Since you suspect an electrical problem, here are a few troubleshooting steps you can try without any special equipment.

Disconnect the connectors from the PDE (Piezo Direct Injector). There are two wires connected to each: a brown wire to pin 1 and a colored wire to pin 2. Turn on the ignition and measure the voltage between the brown wire and ground (cylinder head). The expected value is 0.1-0.4V. Then, clear the error code that is generated.

If you already have the connectors disconnected, you can also measure the resistance between the two contacts on the PDE (not on the wiring harness). The expected value is approximately 0.5 ohms.

It runs smoothly and quietly, but has no power and might stutter a bit when accelerating.

Do you have a power box installed on the pump nozzle connector?

"No, I haven't installed a power box. I don't foresee any problems due to the refurbishment, especially since the components have been running without issues for 1.5 years. The company that refurbished the components has re-checked them at cost price (parts only) and also measured the coil resistance. Everything was okay. Replacing the components with new ones is no longer worthwhile, as the car has 417,000 km. I can work with those values; I'll measure them this weekend. Just to clarify; is the brown wire in the PDE cable harness, which according to the wiring diagram goes directly to the control unit, a ground connection for the PDE? And could there be another connector, connection block, or something similar somewhere other than directly at the head where the connector is located, that could be causing the problem? I'm not worried about the thread of the tensioner; if it strips, I'll install a Helicoil."
By the way, I'm working the night shift until Friday, so I'll only be able to respond in the afternoons and evenings. During the night shift itself, I'll have to see how busy things are.


Regards,


André.

"Sorry, I didn't answer that question earlier. The engine starts well, both when cold and warm, and there are no misfires at idle. When it was very cold, the ASR (Anti-Slip Regulation) light came on more frequently. The error code was "PDE cylinder 4 exceeded regulation limit." However, the engine continued to run normally. I then cleared the error code using VCDS. When accelerating, between 2800-3300 RPM, there were occasional misfires. It felt like it could produce more power, but it didn't. There were no error messages associated with this. These misfires occurred both when the engine was cold and warm. The turbocharger is delivering its power as expected, and all other values seem to be okay. I replaced the timing belt at 408,000 km, and the synchronization angle values are also within range."

Regards,


André.

Hi,

Could you please answer my question about the brown wire that goes directly to the control unit?
If these values are correct, are there any other values I can check at the same time?

Regards,


André.

If the target value is incorrect, you need to use a multimeter to check the wiring from the engine control unit connector to the common rail injector connector for breaks, damage from rodents, etc. This is less likely to be the cause in all four injectors. Then, do the same check from the common rail injector connector to the injectors themselves, specifically the wiring harness you replaced in the cylinder head.
Then there's the engine control unit. That's also unlikely if it's original. You know better than I do whether anyone has tampered with it before. And finally, if all of that is ruled out, then only the PDE (possibly referring to a specific component) remains as the cause.

Okay, I'll let you know on Friday or Saturday. Thanks for the answers.


Regards,


André.

Hello,

"I installed the refurbished components on Saturday. The measured voltage between the brown wire and the cylinder head was 0.3 volts for all connectors. I was unable to reliably measure the resistance of the coils in the PD (Pre-Catalyst) elements because a good contact was not possible. The values from MWB 13 are still normal, while the values from MWB 23 are now between +30 and +50 for all elements. The engine is now running smoothly without any misfires, and it has regained its power."
So, it was indeed due to the PD elements, as you suspected.


Regards,


André.