Replace PDU Cable: Issue Solved

Hi,

After a few cross-connections, I've reached a point where a longitudinal connection (PD) now requires a new wiring harness to the PDE. Unfortunately, unlike with cross-connections, this wiring harness isn't easily removed, which caused the old one to break during removal.

Is there a trick to get the new hose installed without causing any damage? (Customer's vehicle.)

Vehicle: 8E, manufactured in 2005.
Engine: BKE

Greetings.
John.

Warm up!

mullemaus wrote:

Heat up!

EXACTLY , but not too hot.

Thank you, I've already put it in the boiler room .

Besides that, the new hose is much more flexible; it's likely that the plasticizers in the old one have already been leached out.

Unfortunately, replacing the cable set did not achieve the desired result .

The engine is warming up, occasionally sputtering and shaking (similar to a faulty dual-mass flywheel), and eventually, individual cylinders start misfiring, leading to the engine stalling.

As long as it runs smoothly, everything is fine with modules MWB 001, 013, 018, and 023. If it starts spinning erratically or has interruptions, the idle amount (001) is approximately 20mg, 013 is sometimes at its maximum value (3mg), and 128 (=no closing time identification) appears in module 018. Module 023 provides some arbitrary values exceeding 100.

The error memory shows both "electrical fault, PDE" and "limit exceeded," but there is no indication of a problem specific to any particular cylinder.

I can rule out mass errors in the wiring harness of the power distribution module (PDM) because it has been replaced recently.


The engine control unit (ECU) has been opened before and programmed using a BDM tool (there are traces on the BDM port). According to information I received, this happened 4 years ago. There was no thermal paste on the power transistors, so I've added some now.
No change.

Now it's in the freezer, and then I want to try again.



Does anyone have any suggestions on where else I could look?

Unfortunately, the STG cooling system also did not produce any results .

I've noticed that the common vehicle ground on the round connector for the PDE has a resistance of 195 ohms to the vehicle chassis, and when checked with a test lamp, the lamp only glows faintly, and the electric ARF actuator is clicking.
I don't have a wiring diagram handy right now, but there should actually be plenty of ground connection there, right?

Quote:

The idle amount (001) is approximately 20mg

.
= Foam instead of diesel? What pressure is being exerted on the tandem pump? How about a transparent section in the fuel return line?

Best regards, Rainer.

Quote:

What is the pressure at the tandem pump

In the upstream channel at the measurement point: 3.5 bar (low level).
Pre-filled in-tank pump, after filter: approximately 1 bar.

No air bubbles in the return flow .


EDIT: In the meantime, I've tried a few other things...


- Wiring harness between the engine control unit (ECU) and the main connector for the particulate diesel filter (PDE) has been checked - OK.
- The engine was primed with fresh winter diesel fuel directly at the tandem pump.
- Return flow directly to the temperature sensor in the canister;
- Remove the ARF pipe if the exhaust is blocked.
- Removed the intake manifold if the suction path is blocked.

no change.

vwSchrauber wrote:

I noticed that the common vehicle ground at the round connector for the PDE has a resistance of 195 ohms to vehicle ground, and when checking with a test lamp, the lamp only glows faintly, and the electric ARF actuator is clicking. I don't have a wiring diagram handy right now, but there should actually be plenty of ground connection there, right?

No, even the common PDE wire is connected in the (EDC15-) module and therefore goes through an output stage.
Why? To close the pressure drop element (PDE) as quickly as possible at the end of the injection cycle by briefly reversing the control voltage, thereby minimizing harmful afterdripping.

"@ulf: I've also noticed this now – it's the same with both the EDC16U1 (reference vehicle from the company fleet) and the EDC16U34 (problematic Audi)."

Hi,

Here are a few more ideas:

- Seals for PD elements.
- Mass connection via MSG.

Good luck!

The seals facing the engine oil are okay; I've checked them.

Mass: Inside the housing where the engine control unit (ECU) is located, all nearby ground wires are connected using crimp connectors. A 2.5mm² wire then runs to a grounding point on the injection molding machine. Unfortunately, no faults can be found there either.

Interesting detail: the engine control unit (ECU) now has a different part number (according to Ersatzteilfuzzi), and is one of the few ECUs that are available as a replacement part. That's why it only costs about €650 (including tax). Why ?

Try increasing the LL speed slightly. Then test and report back.

That's right - the idea isn't that bad .

EDIT: The LLDZ warm temperature is now at 1000 1/min instead of 880, let's see...

EDIT2: unfortunately, it's not working... the problem remains unaffected by that .

Is that a 16V engine? Then, as a test, try swapping the engine control unit. I seem to remember reading something about that once.

No, it's something quite exotic...

1.9L 8-valve engine with 85 kW and EDC16 control unit.

I'm familiar with the problem on 2.0 16V engines without a DPF. It manifests similarly, but it can often be fixed with a software adjustment. However, in that case, it only affects the idle speed. In my situation, I'm experiencing jerking and stalling even while driving.