ESP spool failure

Hello,

I'm writing because I'm starting to run out of ideas.
After an unexpected failure of the ESP's tensioner roller, the injection timing has been significantly altered, and my (A6 4B, AYM, manufactured in 2002) now won't start.

The following actions were taken:

- The engine was brought to its top dead center (TDC) position, verified through the oil filler opening, and also by removing the vacuum pump and aligning the camshaft lobes.
- The locking mechanism is screwed onto the crankshaft.
- The ESP was locked at the 12 o'clock position using a locking pin.
- New tensioner previously installed.
- Timing belt installed and tensioned for the ESP.
- Then, release all locking mechanisms and rotate the crankshaft pulley twice clockwise to ensure proper alignment.

First launch attempt, unsuccessful.

- The camshaft gear (of the ESP) was loosened and adjusted slightly earlier.

Unsuccessful.

- The camshaft gear was loosened and adjusted slightly towards a later timing.

Unsuccessful.


Should I try to skip a tooth during the root canal treatment and continue with the procedure?

Other observations:
- Diesel fuel is supplied to the fuel injectors via a pipe.
- No smoke development when starting.
- Error memory is empty.

Thank you.

Hello,

Does the pump actually spray?
How is the ESP (Electronic Stability Program) driven by the engine? Is it possible that the crankshaft is rotated by 360 degrees relative to the fuel injection pump? In a 4-stroke engine, there is only one injection event per cylinder for every two revolutions of the crankshaft.

But eventually, some smoke should start coming out of the exhaust.

Best regards, Rainer.

Hi Rainer,

Exactly, and on this point, I unfortunately have to revise my statement.
The test, which involved loosening the banjo bolts on the injector holders and disconnecting the return line to the diesel filter, revealed: not a single drop leaked out. However, a slight bubble was visible on the banjo bolt of cylinders 4 and 1.
Probably some leftover diesel fuel...
Starter spray didn't work either.
Recently, I noticed that there's now air in the system, but the question is, if the engine was running properly before and always started well, where did this air come from? Sure, there could be causal factors, like a defective O-ring, but at first glance, hmm?

The ESP is driven by the camshaft, which is connected to the camshaft drive.
A complete 360° rotation is also a rotation of the crankshaft (OT).
But, as you said, eventually, under certain conditions, it should start smoking, assuming the ESP is functioning correctly. But there's nothing there.
I think the sour apple has finally caught up with me.
I'm trying to finish building my diagnostic connector today so I can at least perform a basic diagnosis using VAG-COM.
According to the current information, there's nothing listed in the MSG system with the WBH identifier. However, that doesn't necessarily mean anything. If necessary, I will also look into the ESP control unit.
It should be noted that the camshafts have already been replaced, and they do not have a proper TDC (Top Dead Center) marking (if you look in through the oil filler neck). Only by disassembling the vacuum pump can one determine when the camshaft is at top dead center (TDC).

Best regards,

The pump can also be plugged in incorrectly. When rotated 180 degrees, the pen also fits in, because there is no hole in that position.
Perhaps the valve gave way because the pump got blocked.
Then she might turn now, but she's not doing anything else.
Air only gets in if there's a leak somewhere in the lines.

christians wrote:

It is also possible to plug the pump in incorrectly. When rotated 180 degrees, the pen also fits in, because there is no hole in that position. Perhaps the valve gave way because the pump got blocked. Then she might turn now, but she's not doing anything else. Air only comes in if the pipes are disconnected somewhere.

That is not the case. The flywheel (ESP) has been unscrewed for adjustment. In this case, only one locking hole is present and it is marked at the 12 o'clock position.
The lines were not disconnected; the locking nuts on the nozzle holders were only loosened for inspection purposes, after first disconnecting the return line to prevent air from entering the system.

There's still air in the system, and I suspect that the feed pump isn't being activated. I'm going to investigate this further, as when I removed the supply line before the filter during the start-up attempt, nothing came out at all. The tank is 35% full, but I currently have it propped up on the side in the front for mounting.

I actually managed to misjudge something like that years ago. It wasn't exactly a masterpiece, but it was possible. The pump's timing belt pulley only has one hole, right?
When rotated 180 degrees, the pen then disappears behind the pulley wheel and fits perfectly right away.

I think.

Okay, that's all for today. I was also given a tip to try holding a canister directly against the ESP inlet. Okay, I'm a little skeptical too, mainly because of the purity aspect, but if it's supposed to help...

Here's another question:
Let's just hypothetically assume that the ESP system has failed, and it's a technical problem, but nothing is stored in the error memory. Would this be a worthwhile consideration, or am I wrong in thinking that? Could it be that the well-known transistor has failed in mine as well?

Today, I tried to remove the air using a vacuum pump. After a long time of pumping and still no diesel reaching the fuel line, I became skeptical. I also noticed a sound that resembled suction. At first, I didn't think much of it. Since nothing was happening, I connected the vacuum pump directly to the diesel filter. Immediately, with just a few pumps, diesel started flowing. Then, I connected the pump after the filter, and the same thing happened. This eliminated the argument that the filter was clogged, as it should have been allowing fuel to flow to the ESP (Exhaust Gas Recirculation) system. FALSE ALARM!
Therefore, my suspicion that the noise was related to air being sucked in was correct, and it's coming specifically from the O-ring. Consequently, the pump cannot build up proper pressure due to the external air intake. That's why I couldn't initially see the air in the supply line, and I believe that if you don't constantly monitor it, it's also not possible to detect, because, according to my assumption, the pre-pump is also working and masking the air intake through the defective O-ring. I hope that's all and that there isn't any more damage.

Declaration: ESP scrap.
After applying back pressure with the pump, I was able to isolate the air leak on the shaft, located after the impeller and at the entrance to the pump housing. So, it seems there's nothing wrong with the O-ring after all.

Does the shaft have any noticeable play when the belt is removed?

christians wrote:

Does the wave have noticeable play when the belt is removed?

No, the casing around the housing is damaged where the pump seal sits. Therefore, this air is being drawn in.