Organ Concert at 1Z Motor

Hello,

I've been around for a while now, and I've been reading through the forum for quite some time. However, I haven't found a thread specifically related to my symptoms yet.

Here are the details of my car:
Volkswagen Golf 3 TDI, manufactured in 1994, 1Z engine, 200,000 km mileage, 90 horsepower.

Okay, and now for my problem. For about 2 months, my Golf hasn't been running like it did when it was new. Above 3000 RPM, it only delivers 'jerky' power. In other words, it accelerates for about 100 RPM, then it stops for a short time... then it accelerates again, then it stops again, and so on. It no longer reaches the easily achieved 4000 RPM, even during longer (>10 minutes) full-load drives. Consequently, the top speed has dropped from a previous 195 km/h to just under 175 km/h.

Okay, so far, nothing new here. The symptoms I've described have been posted a thousand times before. However, I've also noticed that when the windows are down and I accelerate past 3000 RPM, the turbo whistling, along with the power, comes and goes. That is, it whistles, then stops for a short period (less than 1 second), and then the turbo kicks in again, etc. So it sounds like a whistling concert.

Unfortunately, I don't have a way to measure the boost pressure, etc.
However, the fuel filter has been replaced, as well as the diesel filter.

Oh, and one more thing... the thermostat was defective and has been replaced, and the lack of performance appeared after the replacement.

Thank you in advance.
Best regards, Kalle.

Oh yeah, and one more thing... the thermostat was defective and has been replaced, and the lack of performance appeared after the replacement...


It's either a coincidence, or it's only very indirectly related.
'That definitely sounds like a limp-home mode. The 1Z engine is quite tolerant in this regard. If you let off the gas, it will clear the error, meaning a restart of the engine is not necessary. That's why you're experiencing that 'jerky' acceleration. To me, it sounds strongly like a turbocharger pressure problem... Without a Lambda sensor (LDA) or a diagnostic log using VAG 1551 or similar, you're unlikely to get any further.'

hi doc,

Thank you for your quick response.
But why does the emergency mode only activate at 3000 RPM?
In the lower RPM range, it pulls like always! (i.e., from 1900-2900 RPM). It's only above 3000 RPM that you experience this jerking... Could this be related to the fuel injection?

Could you perhaps give me some pointers on where I can still look for errors?

'Thank you.'
kalle

Tips:

- Does the N75 valve (located next to the diesel filter) rattle?
(It's not necessarily audible, but it's noticeable.)

- Are all the coolant hoses and sensors leak-proof? (Especially the one leading to the engine control unit in the coolant reservoir, as mine was completely deteriorated!)

- Are all the turbocharger boost hoses sealed?

That's all I can think of (besides VAG-COM).

m;

But why does the emergency mode only activate at 3000 RPM?


At 3000 RPM, the exhaust flow is much stronger, which means the impeller in the turbocharger is driven much more forcefully. If your boost pressure control (see Martin's tips) is not working correctly, the excessive boost pressure cannot be regulated properly, resulting in a limp mode.

One more tip.

Is your wastegate working?
From below, you should be able to see a pressure sensor near the turbocharger, which could be connected to a rod.

Can this rod be moved?

If your wastegate is stuck, the diaphragm in the wastegate actuator is torn, or the wastegate cannot open for any other reason, the turbo will force a massive amount of air into the engine -> resulting in a limp mode before it "blows up."

m;

Hi,

"As a test, try connecting the high-pressure side of the charger (a connection point somewhere between the charger output and the motor) directly to the charger housing."

If the jerking stops, it's likely due to the boost pressure solenoid valve or a blocked hose for the external pressure (see also the technical article on Sterupneumatics).

Another tip.

Can this rod be moved?


'Should it be able to move manually? Mine didn't. However, it moved smoothly when I applied pressure to the tube towards the can...'

@DocSnydor

'Then you must have a different control unit than the one my 1Z had. It went into emergency mode and had to be restarted. Great on the highway at 140 km/h. I actually had to restart my engine while on the highway at 140 km/h. Afterwards, I figured out that I had to ease off the accelerator up to 140-150 km/h and then I could press it down properly. I did that and spent about 20 km driving very fast. I wanted to investigate the problem, but I didn't have an interface at the time, and when I finally did have my interface, I had my accident.'

Best regards, WarLord.