sporadisch starkes Nageln, dann wieder weg | Posts 64+

Hi! A test drive confirmed that the error, as expected, was not resolved by cleaning the SBV valve.

Since a replacement pump (reconditioned) from Bosch costs €800 , including the return of the old pump, and all the essential components of my pump are still in good condition, I would like to mitigate the problem and am willing to drive with reduced performance (but with €800 more out of my pocket) until a more economically viable alternative becomes available.

The pre-tension force of the SBV spring is increased by inserting cylindrical spacers . If my plan works perfectly, the piston will operate at a higher force level overall (higher spring force = requires higher hydraulic adjustment force), which may overcome the stiffness. However, hydraulic early engagement may no longer be possible because the spring, with the spacer, is already completely compressed beforehand.

Experts, what do you say about that?

Regards,
Holger.

Entry in the secret log of the turbodiesel community, where my highly confidential explanations are guaranteed not to be read by anyone, let alone commented on.

I've at least achieved one partial goal: the harmful 'knocking' noise is gone because the SBV valve piston can no longer reach or gets stuck at the early engagement point. However, it still doesn't seem to follow the target value quickly enough, causing the control limit to be exceeded and the EDC system to go into emergency mode.

Now, I want to reduce the emergency stop function using a 10-cent tuning method. To do this, I need to identify the famous 'wires' 2 and 3 (Ulf probably meant the individual strands of the cable).

Please forgive this pathetic attempt, but expanding or switching to a more economically viable ESP system is not feasible in the short term.

Regards,
Holger.

Well, biodiesel is definitely a pretty dumb idea...
If possible, you should try to remove the piston.

It would also be interesting to check the internal pressure of the pump. It's quite possible that the rotor vane pump and/or the overflow valve have suffered damage, and the internal pressure is no longer sufficient to actuate the injection control unit. If the solenoid valve is truly closing completely, you should get full advance timing if the engine speed is high enough. If that doesn't happen, either the piston or the entire roller ring is likely stuck.
Both of these are common side effects associated with biodiesel. I also posted a picture somewhere here showing how the adjustment piston had broken off due to corrosion at the edge, causing it to become stuck.

CU Gremlin.

So, biodiesel is definitely a very bad idea...
As long as the old seals hold up, I'll keep using this stuff because of the pore-softening agent theory.

If possible, you should try to remove the piston.

Yes, that's my dream. Currently, it's failing due to time constraints and a lack of equipment.

It would also be interesting to know the internal pressure of the pump.

That gives me an interesting idea: How about attaching a pressure gauge to the VP37? It would be excellent as a diagnostic tool.

It is quite possible that the wing cell pump and/or the overflow throttle have suffered damage, and the internal pressure is no longer sufficient to actuate the injection control valve. If the solenoid valve is truly closing 100%, you should get full advance timing if the engine speed is high enough. If that doesn't happen, either the piston or the entire roller ring is likely stuck...

Well, that theory is ruled out because the engine would then suffer from chronic timing issues. However, the opposite is true. The spring force seems too weak for the sticking SBV piston, while the hydraulic force appears to be more than sufficient.

Both are common side effects of biodiesel.

In my opinion, this is less of a problem with biodiesel itself and more of a problem with Bosch. I've had skin contact and smelled both diesel and rapeseed methyl ester (RME), and I have to say that the latter was more pleasant because it at least smells like food. My skin didn't break out, and I'm still alive. So RME can't be *that* bad. Sometimes people act as if it were pure hydrochloric acid. I don't believe in horror stories.

I also posted a picture somewhere around here before, where the adjustable collar had broken off due to corrosion at the edge, and it was completely stuck...

Maybe I'll get around to disassembling my ESP guitar sometime. If I do, I'll post about it.

Sure, here's the translation:

'cu' is a Spanish abbreviation for 'con usted,' which means 'with you.' It's often used in online communication to indicate that someone is available to chat or talk.
Holger.

Both are common side effects of biodiesel.

In my opinion, this is less of a problem with biodiesel itself and more of a problem with Bosch. I've had skin contact and smelled both diesel and rapeseed methyl ester (RME), and I have to say that the latter was more pleasant because it at least smells like food. My skin didn't break out, and I'm still alive. So RME can't be *that* bad. Sometimes people act as if it were pure hydrochloric acid. I don't believe in horror stories.


Bosch has nothing to do with this. Biodiesel simply has certain undesirable properties, especially when it is not produced and stored properly.

Here are some pictures for the fairy tale book:

Biodiesel, however, has some unpleasant properties, especially when it is not produced and stored properly.


Let's rephrase the sentence: Every fuel inevitably has some undesirable properties if it is not properly manufactured, transported, and stored.

'If there's sediment and water in the RME [biodiesel], I believe that's not an RME problem itself, but rather a quality issue. If you were to fill up your tank with diesel containing 20% sulfur and dead rats in Russia, then you would also have a quality problem.'

Regards,
Holger.

Let's rephrase the sentence: Every fuel inevitably has some undesirable properties if it is not properly manufactured, transported, and stored.



That's why Bosch only approves diesel fuel that meets the EN-590 standard.
It simply doesn't have the tendency to decompose itself, bind water, or act as an oxidizing agent.

That's the dilemma... either go back to basics with a naturally aspirated engine and radial piston pumps, or measure the 0-100 km/h acceleration time using a stopwatch.
'Or, consider DI engines with ample power and low fuel consumption, but requiring high-quality gasoline to avoid issues. Interestingly, even TDI drivers in the US have their own challenges with diesel fuel there...'

'By the way, my dealer has already seen several cases of damage caused by biodiesel. However, only one vehicle hasn't experienced any issues. The owner of that vehicle runs a biodiesel factory that produces fuel according to the EN 51606 or 14214 standards.'
But as long as these standards are not legally binding and properly enforced (specifically at the fuel pump), anyone can tamper with the fuel as they please.
And RME (presumably referring to a specific product or item) should not be left unused for more than 4 weeks.

Nevertheless, an autopsy of your pump would certainly be helpful in determining the actual cause of the defect.

CU Gremlin.

Hey Gremlin, also auch on vacation? Considering the time of day, it seems like things are really busy in this forum right now.

I almost exclusively refuel with RME at AVIA gas stations. These belong to the 'Working Group for Quality Control of Biodiesel' and, of course, have the DIN EN 14214 standard displayed at the pump.

I don't know if it will achieve anything besides easing someone's conscience. When I decide to 'autopsy' my pump depends on the circumstances.

-how long it will remain functional in its current state.
-when I can find a bargain on replacement pumps.
- when the timing belt needs to be replaced.
(whichever happens first).

Sure, Gremlin, could you do me a favor? Which ESP (Electronic Stability Program) is compatible with my system for purely mechanical installation? If it doesn't fit in terms of flow rate, I can probably find a way to make it work.

Mine has...

Article number: 0 986 440 503.
Gebrauchsnr. VE4/10E2100R701-3
Boschnr. 0460404967

Regards,
Holger.

Yay, I got rid of the limp mode with the 10ct tuning!

However, I had to reduce the trimmer resistor to approximately 100 ohms in order to achieve acceleration similar to what it was before.

Additional features:
- Engine noise: normal.
- Exhaust fumes (despite the use of biodiesel): odorless/neutral.
- Soot: None observed.

Unfortunately, the two diodes do not completely eliminate the jerking, but it can be avoided by adjusting your driving style.

Hopefully, the pump is otherwise in good condition.

Regards,
Holger.

My God, what a shoddy job... but the main thing is that the box rolls .
When overtaking or in other situations, you should still always keep the emergency mode and potential interruptions in mind.

Don't worry, I'm only driving 550 km on the highway tonight. So, no overtaking.

The most important thing is that the ESP doesn't fail unexpectedly . But it has had the defect for 4 weeks already and hasn't exploded yet.

By the way, I have the impression that it now even pulls more than before the SBV defect. I will probably continue with the 0ct tuning even with a new or repaired pump. } In addition, I'm placing the intake hose in the radiator wall (to catch airflow), so that I get a few mbar of boost pressure due to back pressure.
It would be convenient if the 0ct tuning could be automatically activated gently starting around 2000 RPM. Is it possible to easily tap into the engine speed signal somewhere, and what does that signal look like?

Best regards,

Furthermore, I place the nozzle against the radiator wall (using airflow), which allows me to achieve a few millibars of boost pressure due to back pressure.


According to Bosch, the creature is said to undergo a thousand-year digestion process within the Sarlacc pit on Carkoon.

unless you don't have an LLM

CU Gremlin.

@Holger

Congratulations! The main thing is that it works , let's see how long. Your DIY project sounds almost like the legendary VCR I was able to repair 5 years ago. The stated error was a picture problem with purchased cassettes... but nothing on that device was original anymore; no spring was in its standard position... it was absolutely crazy that the VCR produced a perfect image despite all the adjusted tape positions and track alignments when recording something yourself... it just goes to show .

Well, I'll be optimizing my AEL a little bit over the next few days, and maybe I'll fix some of its quirks.

But: leave the air intake where it is. If it's exposed and facing forward, rainwater or spray from passing trucks can get into it, which could cause major problems...

Tuppie.

Hey everyone! I'm checking in again, this time from my vacation spot via an analog modem. For short trips without using the highway, I was able to permanently disable the 0ct tuning.

But now, here's the strange thing: The limp mode is still there, but overall, the car seems to be running better than it did before the 0ct tuning / before the long highway drive. Or rather, the limp mode seems to have become less severe. I can easily reach a speed of 100 km/h on flat roads. Perhaps the fuel injection timing has been optimized by chance?

Regarding fuel consumption: Despite the fixed injection start due to the hanging SVB (stroke valve) piston, it's very low. With one tank of fuel (35L), I drove 700km until the reserve light came on. That means a consumption of less than 5L per 100km. Apparently, I have a fuel-efficient injection start.

Regards,
Holger.

PS: I'll check the Yellow Pages for 'Schrotti' right away. I don't think they'll have my pump, but for research purposes, I might also take a broken one.

Hi!

My vacation is coming to an end today , and I have already driven 1400 km with the hanging secondary valve lifter piston and the spacer in front of the secondary valve spring.

The 0ct tuning seems to have a faulty cross-resistance, as I've recently noticed a very slight, irregular stutter even under full load. Perhaps the cheap trim potentiometer or the switch has contact problems. By the way, the tuning is located directly behind the radiator and gets sprayed with water in wet weather. Well, now there are no more track days planned, so I can disable the tuning.

Now I can finally take my time to look for a replacement ESP.

Regards,
Holger.

Hi! After 10,000 km with a stuck SBV piston, something incredible happened.

Since I returned from my second vacation and started the engine one morning, the limp mode and knocking have disappeared. I've been driving like this for a week now. Apparently, the fuel injection timing control system is working again. The sound of the engine is incredibly smooth. It feels like I'm in a powerful, large-displacement gasoline engine compared to before. Only the deep bass of the engine vibrations is audible, no harsh noises. This is completely unusual for me.

And that's despite the fact that there's a spacer in front of the valve spring to increase its preload! So, the mechanics have been tampered with, and the valve lifter is more likely to hit a mechanical early stop than it would be originally. Those who are familiar with this thread know that the spacer was only a temporary measure to reduce the extreme and harmful premature lift that the hanging valve lifter caused.

It appears that my driving style and the routes I take never cause me to reach engine speeds where the SBV piston would hit the early timing advance limit. The emergency mode hasn't reappeared. Therefore, the current mechanical adjustment range seems sufficient to provide the early timing advance required by the fuel map at engine speeds up to approximately 2800 RPM.

'For the last 5000 km, I've been using a mixture of RME and Pöl. With this mixture, the emergency running mode has occasionally turned on for a few seconds. Could the Pöl have something to do with the self-repair process of my ESP?'

Let's see how long this self-repair lasts. It's already covered 500 km.

It's certainly possible to speculate a lot. For example, that the damaged area in the cylinder bore of the SBV piston has somehow smoothed out over time, or that some foreign object has disappeared from the critical location.

Regards,
Holger.