Turbocharger Leak: Funny Discovery!

hi all,

'Today, I happened to notice something while the hood was open that surprised me quite a bit. I drive a Passat 1.9 TDI with 110 horsepower, which, when it came out in 1996, was chipped shortly after about 5000 km. Back then, there weren't many providers who offered chipping for common rail diesel vehicles, especially this model!'

'I'm definitely going to check the hose that runs from the pressure sensor on the turbocharger into the engine compartment. I noticed that the hose is quite loose where it connects to the sensor, so you can easily pull it off. So, I thought I should take a look at the rest of the hose.'

'And then I saw that the hose in the middle had simply been cut and plugged with a piece of plastic.'

'That's not normal! How can the turbocharger adjust to pressure if the wastegate isn't working? And it probably isn't working if the vacuum sensor isn't receiving a vacuum signal...'

Did they simply not have any other options back then, or what? Does this damage my charger? Is the position of the VTG shims now always fully open or fully closed... meaning full power or reduced power?

Should I replace the entire hose or just remove that plastic piece in the middle?

Please help me, this is already bothering me!

'Thank you.'
chris

Are you absolutely sure that it has a common rail system?

Hi.

You definitely don't have a common rail diesel engine. Volkswagen doesn't actually produce those. Yours has a completely normal fuel injection pump.

The can that you are holding, which you think is the VGT compensation canister, is probably the AGR canister. The AGR in your vehicle was likely deactivated by the previous owner. This is not a reason to get upset; instead, you should be grateful to him .

If the hose to the VGT (Variable Geometry Turbocharger) is indeed blocked, your TDI will, at best, have the performance of an SDI engine because no boost pressure can be generated.

Don't worry, if your car offers good performance, everything is fine.

Best regards, Claus .

It can't be! I have an AFN engine... it should have common rail... or does it not matter? Anyway, it has a VTG turbocharger in it... or does it not? Help meeee! Aaaah, I'm freaking out here lol

Okay, and nowas... hehe. I think I can probably tell the difference between an AGR valve and a VTG valve. One is located on the intake side, while the other is on the turbo outlet side. And since I personally disabled the AGR valve, it's probably not that one causing the issue. Grins.

The AFN engine has a VTG turbocharger and uses a "distributor injection pump" as its fuel injection system, which is *not* common rail (CR). Common rail systems work with a high-pressure fuel rail that delivers significantly more injection pressure than a distributor injection pump ever could. As mentioned before, VAG (Volkswagen Group) does not offer common rail technology for this engine, or at least not yet (there were rumors somewhere that they might want to develop something like that).

How does your car drive?

If what you described happened to the VTG vacuum adjustment system, there would be almost no boost pressure because the system is designed to fail safely: a failure of the pressure sensor or control circuit results in a *minimum* amount of boost pressure, not a maximum. Therefore, in such a case, the car would likely have a maximum power output of around 60-70 horsepower and perform accordingly.

Best regards,

January.

It's incredibly fast; it spins the wheels in the first three gears. It was on a dyno test a month ago and produced 132 horsepower at the wheels.

That can't be right... but it definitely seems to be the valve on the loader. Would that mean the setting is at its minimum? Like, the position of the bucket blades on the loader?

I don't understand. I'm desperate.

I'm sorry, I don't understand the question. Can you please rephrase it?

With a detached or disconnected hose, the position of the charging flaps would be at its minimum, as I mentioned -> resulting in very little charging pressure.

What you described still sounds like the usual cover-up method for the AGR (Automatic Gearbox), compare it to the article on the main page.

Applying this to the VTG adjustment results in a loss of power, unless the VTG linkage is locked in the maximum position. This, in turn, would cause the system to go into emergency mode (unless the chip prevents it), and could damage the turbocharger.

How does the VTG adjustment system work on your vehicle? There's also a technical article about it on the website (www.dieselschrauber.de).

But I can't imagine that whoever chipped the engine somehow tampered with the VTG (variable turbine geometry)... the driver would have long since crashed due to over-revving.

Best regards,

January.

I don't understand this. Especially, I don't get why the pressure regulates at 1.1 bar. Before that, there were short spikes up to 1.5 bar, which are normal, especially with a different air filter.

I have no idea what they were thinking. I can't really tell about the support structure right now; it's hard to reach. I need to disassemble it and take a closer look... and also call my mechanic.

I'm sorry, I don't understand the word 'cuall.' Could you please provide more context or clarify your request?

P.S. I know it sounds like 'agri stuff,' but as I said...
The AGR module was developed in the same way as the 'elephant hose' modification.

Hi.

Okay, first of all: A hose loosely attached to the VTG canister doesn't necessarily cause malfunctions as long as it's partially sealed.
He can't actually fall off because there is never any overpressure inside the hose that could push him down. On the contrary, the vacuum sucks him further onto the nozzle.

If the plastic plug in the VTG hose were completely sealed, no boost pressure would build up – at least not at the usual low engine speeds, but possibly only gradually starting at around 2500 or 3000 rpm, and in any case, too little.

I suspect that the plug is a nozzle with a small cross-section that makes the response of the VTG (Variable Turbine Geometry) adjustment sluggish.
This also explains the high overspeed values (up to 1.5 bar) reported by IMO, because the impeller blades cannot be operated at lower pressures quickly enough when the engine is running at full load in low gears.

The purpose of the device could be to reduce black smoke emissions during the transition from partial to full load by momentarily "overloading" the engine with air.

YES ULF... I think we're getting closer to the solution now.

'I only didn't quite understand the last paragraph... what did you refer to with that? What do you mean by that?'

'The purpose of the device could be to reduce soot emissions during the transition from partial to full load.'

I know what it does, but which can are you talking about? The pressure relief can? Sorry, I'm probably just not understanding.

What would happen if I removed that part (the valve) and replaced it with a completely new hose? Would I then get too much pressure too quickly?

Okay, I don't actually have that problem in the lower gears when I'm using full throttle. It's more of an issue when, for example, I'm driving in fourth gear at around 2000 RPM and then start pressing the accelerator gently. In that case, the boost pressure gradually increases to about 1.5 bar. Sometimes it can even stay there for a few seconds before settling down to 1.1 bar.

It would be great if I could now assess what's advisable and what's not. I mean, the car is running well, and I can't really complain. But maybe it could run even better if the hose were replaced with a new one without a valve.

Thank you very much for your active participation!

chris
Sure, no problem. Here's the translation:

'Thank you in advance.'

Hi.

Quote:

I just didn't quite understand the last paragraph... what did you refer to with that? What do you mean by that? "The purpose of the device could be to reduce the black smoke emissions when transitioning from partial to full load." I know what it does, but which can? The pressure can? Sorry, I'm probably just not understanding.

Sorry, I meant "nozzle" instead of "can" = the plastic piece in the hose.

While idling and until the boost pressure reaches its target value, the turbocharger is operating with a "high vacuum," which means it's building up maximum boost pressure.

When the target value is reached, the variable geometry turbine (VGT) must be adjusted quickly towards a setting that reduces pressure buildup to prevent excessive boost pressure.
To achieve this, the vacuum inside the charging chamber is reduced, which means that some air flows into the chamber.
And that's precisely what the nozzle in the hose delays. This means the variable geometry turbine (VTG) position isn't adjusted quickly enough towards "boost pressure reduction," which causes the boost pressure to rise too high (similar to a jammed VTG).

If you remove the nozzle from the hose, the pressure peaks would likely be reduced to around 1.5 bar. It is possible that this could lead to increased soot emissions when accelerating.

Okay, it's not like the amount of rust matters that much anymore, haha.

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

'cu' is a Spanish abbreviation for 'con usted,' which means 'with you.' It is often used in online communication and social media as a way to express affection or intimacy.

Here are some examples of how 'cu' can be used:

* 'Te amo cu!' (I love you!)
* 'Eres mi todo cu.' (You are my everything.)
* 'No puedo vivir sin ti cu.' (I can't live without you.)

It is important to note that the use of 'cu' may not be appropriate in all situations. For example, it would likely be inappropriate to use 'cu' when communicating with someone who is older than you or who you do not know well.

Jan6K wrote:

CR works with a high-pressure injection rail that delivers significantly more injection pressure than a VE system ever could.

CR, 1st generation, 1350 bar.
CR 2nd generation, 1600 bar (as far as I remember).

V6 TDI 110 kW 1500 bar with VP 44 injection pump [4].
V6 TDI 132 kW with 1850 bar pressure and VP 44-SIII injection pump.
(Source: Tuneline Tech News)

Best regards,
Crunch.

Wow, I wouldn't have expected that!

What is the typical price range for 1.9-liter four-cylinder engines with VE injection?

The PD value is likely to be just over 2000, correct?

Best regards,

January.

Jan6K wrote:

What is the price range for 1.9-liter four-cylinder engines with VE injection? The PD value is likely to be just over 2000, correct?

1991:
4-cylinder TDI engine with 66 kW (90 hp) and 182 Nm of torque.
Axial piston injection pump with 950 bar pressure.

1995:
4-cylinder TDI engine with 81 kW (110 hp) and 225 Nm of torque.
Axial piston injection pump with 1100 bar pressure.
Variable Geometry Turbocharger (VGT).

1998:
PD with 2050 bar.

(Source: Tuneline Tech News)

I don't know if the newer electric vehicle motors have higher injection pressures.

Best regards,
Crunch.