Refurbishing an AFB 2.5 TDI injection pump

Hello everyone,
On Sunday afternoon, the glorious AFB spontaneously quit working without any prior warning. I didn't have the time or inclination to troubleshoot the issue myself, so I went straight to the friendly mechanic, whom I know well as an AFB owner. The engine control unit's fault memory reported an error in the fuel injection pump control unit. The engine stalled while driving and could not be restarted. Therefore, the friendly person would like to replace the entire pump.
"Can anyone recommend a professional who can replace the fuel injection pump control unit, someone who isn't affiliated with Bosch AG? Also, what's the approximate cost involved when bringing in a defective pump for this type of repair?"
Thank you for your messages.

Best regards, Marco.

Deleted as requested.

Hello Marco...

What mistake did the friendly person identify?

Steve.

Hi diesel.gustav!

What is the approximate replacement cost of a VP44 injection pump at Bosch?

Back then, when I thought "friendly" meant helpful, they were talking about 1500 euros.


greetings: Marko

The VP 44 costs €1392 for replacement at VW.
It's about 50 EUR cheaper at Bosch, including all discounts and shipping costs.

But it's not just that the tank is empty, is it?

The VP44 fuel injection pump must not run dry, so it will shut off if the fuel level is too low.

Sorry, but I just wanted to remind you .

(I learned everything here, thanks guys.)

m;

The tank is about 75% full of commercially available diesel fuel - my local mechanic initially suspected this as the cause, but it turned out not to be the problem.
Thank you anyway!

Best regards, Marco.

Well...

Diesel in the tank doesn't necessarily mean it will actually reach the pump.

What specific error code was read?

CU Gremlin.

Hello,

'It certainly wouldn't hurt to check the fuel pump (the one in the tank). It's failed twice on my car (A4-AFB). I experienced intermittent issues while driving, with the engine warning light flashing, until the car eventually stopped after a few kilometers. There were no relevant error codes stored. I can imagine that the electronics might diagnose a faulty pump even when the problem is actually just a lack of fuel. What's actually happening there? Is there a vacuum in the fuel line? Or is it drawing air somewhere, perhaps at the filter?' In any case, the injection start control should no longer be functioning.

@ TKN

The jerking motion and subsequent engine shutdown "simulated" a malfunction in the electronics.

Since the VP44 fuel injection pump must never run dry, the engine control unit begins to simulate misfires when there is a lack of fuel. If the driver does not react (e.g., by turning off the engine), the electronics will automatically shut off the engine.

Why, however, was there nothing in the error memory...?

m;

@dieselmartin

It's likely that detecting a fuel shortage due to a faulty pre-pump, if at all possible, would be difficult. I'm not aware of any pressure sensors installed anywhere in the fuel line to detect a faulty fuel pump. The float sensor in the tank continues to report 'all OK.' It wasn't as if the engine immediately stalled after a brief hesitation. After the initial hesitation, I reduced the throttle, and it recovered. Then, gradually increasing the throttle to full power, the hesitation with the flashing warning light returned, until it eventually couldn't recover. I therefore assume that the VP44 fuel pump is still self-priming enough with low throttle to draw enough fuel. Once the riverbank has been eroded, that's it.
Thinking about it, the VP44 seems to be quite robust...

The fault memory was read out at the dealer using the standard diagnostic tool 5051, and it reported the error codes "1318-37" and "1318-47", which indicate "Injector control unit fault."
The pump was replaced today, and the first 200 kilometers gave me a pretty good impression - the car drives like it did before. Of course, I would have liked to have spent less than 1700 EUR on it, but the invoice only listed the fuel pump, labor, and a few small items. I assume the problem was actually in the pump's control unit. By the way, the engine didn't show any signs of hesitation, power loss, or other issues before the problem occurred. From one second to the next, it just died, and the instruments behaved normally, as if I had simply switched off the engine.
How is anyone supposed to make sense of that?

Thank you for your contributions!

Regards,

Marco.

*lol*

'I laughed at the first sentence.'
'As an AFB driver, I would of course use the informal 'du' with my friends.'

As someone who drives an AFB vehicle, I can relate perfectly; my car spends more time in the workshop than on the road.

Have fun with it anyway.

Stefan.

I have one more question.

Does the AFB really have an additional pump in the rear tank?

I'm familiar with this from my 4-cylinder VP-TDIs, but in those engines, there's no pump installed.

Thank you for the clarification.
arne

Hi Arne!

Okay, because the AFB, like the AKE, has the VP 44 inside.
Unfortunately, these things are very sensitive to air quality.


cu: Marko

Hello everyone!

You're giving me something to think about. Last year, a flying rock broke the fuel line on my A6. It's understandable that it would have jerked and then stalled. After that, some fuel continued to leak out of the tank on its own (with the ignition off). But regardless, after I managed to install the new fuel line, I simply (and naively) kept trying to start it until the good 92 Ah battery was completely drained. I got a tractor and used its 88 Ah battery to keep trying to start it until it finally started. It didn't register any errors in the error memory, and it runs like it did before. However, a few days later, I experienced the effect of it simply stalling while exiting onto a highway. It can then be restarted without any problems. Okay, I have another VP44 in reserve, so if something had gone wrong...

Best regards,
Frank

99' A6 with 'not' AFB, but still a V6 TDI.