Boost Pressure > 0.5 bar: Only with heavy soot

- Golf 2 TD engine with JR modification and synthetic low-temperature oil.

'Recently, the check engine light came on, and it's only now that I've noticed the boost pressure is too low.'
He didn't go above 0.25; then I replaced the spark plugs and air filter, but there was no improvement.
Then I further adjusted the boost control screw on the ESP, which increased the power. The boost pressure can reach up to 0.5 bar, and beyond that, only more power (boost pressure) is achieved, but – in my opinion – the soot limit has already been significantly exceeded.
Why can't he even reach the standard charging pressure without misfiring?
The liquid lines and hoses are sealed; I have already checked this.

Does anyone have any ideas?

euro

Is the wastegate stuck open?

Why are you turning off the ESP if the turbo isn't working?

m;

Review the UI?

What is a JR with SB LLK?
Self-built or a liquid-cooled system for a single-cylinder engine?

Is the fun over?

m;

Review the UI?

-- What do you mean?

What is a JR with SB LLK?
Self-built or a liquid-cooled system for a single-cylinder engine?

-- It's a JR (Junior) model with an original LLK (likely referring to a specific component) from SB (presumably a manufacturer); a custom build using original parts.

Is the fun over?

-- I have already checked, and the hoses and connections are leak-proof.

Is the wastegate stuck open?

-- I can move the rod with my hand, although it requires considerable force, and it then snaps back with a noticeable 'pop.'

Why are you turning off the ESP if the turbo isn't working?

-- The turbocharger is already working (0.25 bar), and if it produces more exhaust gases (->adjusting screw), then the turbocharger will actually work even more (0.5 bar) .

euro

Quote:

-- The turbo is already working (0.25 bar), and if it produces more exhaust gases (->adjusting screw), then the turbo will actually work even more (0.5 bar) icon_smile.gif.

"Nevertheless, I believe it's the wrong approach."
If you have a headache, a 9mm bullet through the lung might also help...

... but I'm going to take an aspirin.

turns the turbine shaft slightly and without excessive play.

euro wrote:

- Golf 2 TD JR engine with SB synthetic oil and coolant. "Recently, the check engine light came on, and it's only now that I've noticed the boost pressure is too low." He didn't go above 0.25; then I replaced the spark plugs and air filter, but there was no improvement. Then I further adjusted the boost control screw on the ESP, which increased the power. The boost pressure can reach up to 0.5 bar, and beyond that, only more power (boost pressure) is achieved, but – in my opinion – the soot limit has already been significantly exceeded. Why can't he even reach the standard charging pressure without misfiring? The liquid lines and hoses are sealed; I have already checked this. Does anyone have any ideas? euro

Enjoy your meal!

How is it measured?
At standstill or under full load while driving?
(I always drive full throttle in third gear when going uphill.)

If it doesn't reach 0.7 bar under full load, something is not right.

Are the fuel injectors okay?
Start date of funding?
Tax deadlines?
Is the boost pressure enrichment cone free and properly adjusted?
...

Hi, Jockel.

How is it measured?
At standstill or under full load while driving?
(I always drive full throttle in third gear when going uphill.)

-- Measured while driving uphill at full throttle for approximately 5 kilometers (in 3rd gear); and also while driving at full throttle on the highway in 5th gear.

Does the turbine shaft rotate smoothly and with minimal play?

-- Today, I disconnected the hose to the air filter housing and manually rotated the turbine wheel.
Observed:
He hasn't played a single game.
2. Does it rotate easily? (This is relative!) Could someone please tell me if, during this test, when the turbo is manually nudged, it should continue to spin on its own for a short time?
That's not the case with mine!
He's definitely moving around.

P.S. The injector nozzle adjustment screw on the ESP was leaking, and to replace it (the O-ring), the screw had to be completely removed. That's why I initially turned that screw, before I had the idea to try to get the turbo to spool up.

Okay, another thing: I could try swapping the ESD (electronic solenoid valve) with the one from my Jetta (also with a JR engine). Do you think that would be a good idea, or would I need to replace the seals again?
I had previously ordered seals from the Bosch service, but those were just metal plates that taper on one side. Are those the ones I need?

What I also noticed today is that, under the same operating conditions, it produces different amounts of smoke?! (same road, same engine temperature, same gear).

Regards,
euro

If you manually spin your turbocharger, it should still have some resistance. Of course, this depends on how hot or cold it is. Based on what you're describing, it sounds like it's spinning too heavily and therefore can't build up the correct pressure. The "rushing" sound is normal because you're giving it more diesel and less air, which means it's not burning everything completely. Try changing the oil, and hopefully your turbocharger will work better. If not, you might need a replacement.

euro wrote:

Does the turbine shaft rotate smoothly and with minimal play? -- Today, I disconnected the hose to the air filter box and manually rotated the turbine wheel. Observed: He hasn't played a single game. 2. Does it rotate easily? (This is relative!) Could someone please tell me if, during this test, when the turbo is manually nudged, it should continue to spin on its own for a short time? That's not the case with mine! He is definitely moving.

A bearing wave typically sits in engine oil. Depending on the viscosity, the rotational feel can therefore be more or less thick/clumpy.
If you tilt the impeller while rotating it (perceptible play = approximately 0.5 mm), it becomes even more difficult to turn, but there should be no audible scraping!
Due to the low mass of the breech, it barely recoils when manually loaded (less than 1 second), except possibly with ball-bearing-equipped loading mechanisms.

Warning signs include grinding noises during rotation, uneven rotational resistance (like a dirty thread), or high rotational resistance (when it's difficult to turn the shaft even with two fingertips), and absolutely no detectable play or looseness.

I rechecked the charging behavior and the engine's willingness to rev while the engine was warm, and both seem quite normal now.
But even so, the boost pressure is still not sufficient.

I can't even begin to explain what I fixed yesterday and what's happening now! So, I'm sending out a big 'HELP' to everyone again.

Yesterday, I took the time to fix my leaking diesel line, specifically at the point where the T-piece connects to the auxiliary heater, by replacing it with a new piece of hose.
I had hoped that this might improve performance slightly, as where diesel was leaking, air might also be getting sucked in. Now it's sealed, but the performance has actually decreased further, and the maximum boost pressure has dropped to 0.25.
I'm speechless; how can it possibly run better with a leaky fuel line than with a sealed one?
As a final thought, I could imagine that he might be drawing air in through the auxiliary heater; could that be the case?
I also removed the fuel level sensor and checked it for any blockages, but it appears to be in perfect working order.

euro

Okay, I'm going to put myself out there.

Does the engine have significantly less power than before? What is the top speed?

Are you sure that your LDA is displaying the correct value, and are you measuring at the right location?

The engine has significantly less power than our Jetta TD WITHOUT a turbocharger.
The LDA is new and was connected in the correct location.

Today, I went out to a more rural area again and let the engine rev high with the hood open, and I noticed something.

At very high RPMs – and, to my knowledge, only at these RPMs is any noticeable LD produced while the engine is stationary – a small puff of exhaust suddenly emerges from the area below the turbocharger, roughly on the intake side.

Question: What could that be, and where is it coming from?

I thought it might be coming from the connection to the coolant hose, but I checked that and it's not coming from there. It could be coming directly from the turbocharger or from the exhaust manifold.

'Does anyone have a picture that shows the internal structure? Everything is so enclosed that you can't see anything without disassembling it.'

If the exhaust manifold has a leak, it can't build up back pressure, right? Or am I mistaken?

Sure, here is the translation of the text from German to English:

'Hello'
euro

.. who now hopes to finally be very close to solving the problem, which is now driving him to despair .

"That's very possible if the exhaust manifold has a leak. Because the energy of the exhaust gases is converted into power in the turbine... so you should take a small mirror and check. A leak in that area should also make a somewhat louder noise, especially before the turbocharger."

Can I use the following procedure to check if there is any loss of boost pressure somewhere?

1. Disconnect the hose connected to the LDA (Lean Direct Injection) and install a valve (e.g., a bicycle valve).
2. Seal (or block) the intake side of the charger.
3. Using a compressor, apply pressure to the hose through the valve.

Question: Should the pressure that builds up be contained, or is there another place where the pressure could escape?
I can only think of 'valves' right now, or am I making a mistake?

Yesterday, I followed the procedure described above and noticed that the pressure appeared only about 10 seconds after turning off the compressor. I was hoping to hear a hissing sound somewhere, but there was none. Nevertheless, I added a second hose clamp to each of the hoses of the heat pump to be absolutely sure.

'And something else I noticed yesterday: When I disconnect the hose to the LDA (Linear Drive Actuator) of the ESP (Electronic Stability Program) and drive with it disconnected, the acceleration is just as good (or even slightly more responsive) as when the hose is properly connected.'
Maximum boost pressure is currently 0.45. No soot detected, fuel injection screw returned to its original position.

euro

Check the engine compartment for signs of exhaust leaks around the exhaust manifold/turbocharger and the firewall. Use a mirror and flashlight to look for broken studs. If exhaust is escaping, it's being wasted and not going to the turbo. I've experienced this in both my Golf and Bulli. It results in reduced power and increased fuel consumption. If everything seems tight, try driving without the muffler (not as loud on a diesel), as it could be clogged internally.

Since the problem (maximum LD = 0.25 Bar) still persists, and I won't have time to look into it again until later, I would appreciate your help once more!

Yesterday, I pressure tested the coolant system, including the hoses. Even at 1.1 bar, there was no noticeable pressure loss. Therefore, the coolant system and the hoses are leak-free.

'However, I've noticed that when I include the turbocharger in the system being pressurized, the pressure is lost. So, if I close the inlet on the turbocharger, leave the hose from the turbocharger to the intercooler connected, and disconnect the hose from the intercooler to the intake manifold on the manifold side, and then apply pressure there, the pressure is lost.'

Is this normal? Is the pressure being lost after the turbocharger? Could the membrane in the wastegate valve be defective?
Basically, I'm wondering if enough pressure can escape at the locations described to result in a low differential pressure (DP) of only 0.25 bar.

The turbo spins just as easily (badly) by hand as the one in my Jetta TD. It also doesn't make any noises.

However, I've noticed more and more that when the vehicle reaches its top speed of approximately 160 km/h with a propane pressure of 0.25 bar, it doesn't produce any soot at all.
'So, is it correct for me to focus my troubleshooting on the charger, or could it also be related to the ESP (Electronic Stability Program)?'

It would be great if I could get an expert opinion on whether a misadjusted ESP (faulty ESDs, a stuck/defective fuel injector, incorrectly mounted throttle cable, etc.) could lead to such a loss of power.

Regards,
euro