Passat 1Z: Low Power Issues & Solutions

Hello,
I'm new here and incredibly impressed by the amount of specialized knowledge that's available.
'Maybe you can help me, I'm really desperate. So, here's the situation: I bought a 1995 Passat station wagon with a 1Z/90 HP engine, fixed some bodywork issues, and was happy with my bargain. It had poor performance at higher RPMs, and I thought I could fix it! Unfortunately, VW TDI engines are much more complicated than I thought. I've already read a lot in articles and checked the MAF sensor, EGR valve, NHG (NOx sensor), turbocharger (even removed it), and all the common issues mentioned here (fuel lines, injectors, etc.), even inspected the entire exhaust system – nothing! I ordered a diagnostic tool with VAG-Com software from an online store, and it shows error code 0550, with the subcode 17-10, but it's not the NHG sensor; I checked it with a knock test. What is the 'Ventil für Einspritzbeginn N 108' (injector start valve), and more importantly, where is it located? How can I test it? The engine loses power at higher RPMs, especially in higher gears, starting at relatively low RPMs, around 2300 RPM in 5th gear, and the maximum speed I can achieve after a lot of struggling is around 150 km/h.'
Using VAG-Com, I noticed something. In a friend's Golf, the fuel injection value per cycle, which is displayed as 35.2 mg under full load, is only briefly displayed in my car under full load, and then jumps to around 20 mg/cycle. What does this indicate?
Thank you to everyone who takes the time to answer and help me.
Gaggi.

Hello Gaggi,

What does the boost pressure indicate? Have you checked the magnetic valve for boost pressure regulation yet? Is the catalytic converter really clear?

To work through it:
/viewtopic.php?t=3322

Hi,
This is the needle lift valve. There is only one such valve, which is used by the engine control unit to control the start of injection and the amount of fuel injected. It is the valve for the injection start (NHG). If this valve provides values that deviate too far from the possible standard program, the engine control unit receives a command to switch the machine into emergency mode. In this mode, the machine is throttled back to a minimum power level to avoid potential damage.
If this injector nozzle holder (INH) is defective, the engine may run continuously, but you might smell unburned diesel fuel in the exhaust because the INH may no longer open and close at the correct time. Inside the INH, there are small guide sleeves; if one of these is broken, the nozzle will become stuck in the INH, and that's usually the end of it.
Here's a tip: If the needle lift solenoid is defective, you can also use the one from the Audi Z1 engine. It has a different part number, but it's identical to the one for VW.

mani64 wrote:

Hi, This is the needle lift valve. There is only one such valve, which is used by the engine control unit to control the start of injection and the amount of fuel injected. It is the valve for the injection start (NHG). If this valve provides values that deviate too far from the possible standard program, the engine control unit receives a command to switch the machine into emergency mode. In this mode, the machine is throttled back to a minimum power level to avoid potential damage. If this Nhg (needle lift governor) is defective, the machine may run continuously, but you might smell unburned diesel fuel in the exhaust, because the needle lift governor may no longer open and close at the correct time.

Oh oh, it seems someone has thrown the NHG (German building code) and the valve for the start of injection into one pot, stirred it vigorously, and then randomly selected some bits and pieces to write about...

If you think that our article...
Ich kann den Inhalt dieser URL nicht abrufen, da ich keinen Zugriff auf das Internet habe. Bitte gib mir den Text, den du übersetzt haben möchtest.
If there are areas that need improvement, we are open to suggestions .

ulf wrote:

If you think that our article I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL. If there are areas that need improvement, we are open to suggestions

.

I have a question: Which direction of "pump rotation" indicates early timing, and which indicates late timing?

Okay, so, if I'm standing in front of the car (and looking at the engine and the ESP), and I want to adjust the injection timing, should I turn the pump clockwise or counterclockwise? How many degrees (or mm/cm) of rotation correspond to how many degrees of injection timing? Or, to put it more simply: How much do I need to turn/adjust the pump to shift, for example, 1/4 of the tolerance range?

"Well, that's logical, right? Look at the belt drive; it shows you the direction of rotation. The crankshaft, so to speak, "pulls" the timing belt (there's a tensioner in the unloaded state). "Early" means earlier in terms of rotation direction, and "late" means later in terms of rotation direction. The cm measurements are meaningless; it's a gradual adjustment."