1.9 TD No Power? Troubleshooting Guide.

Hello forum,

I believe that with this wealth of knowledge, I will receive an adequate answer to my seemingly unsolvable problem.

The problem car is a VW Golf III Variant, 1.9L TD, manufactured in January 1994, with engine code AAZ.
When I bought the car, as a used vehicle, I later noticed on the highway that it actually had very little power. The top speed of 100-120 km/h was reached in 4th gear, and it was almost impossible to maintain that speed in 5th gear. At first, I noticed that an injector line had broken, and all the diesel was leaking out. I thought that replacing the line would solve this obvious problem. However, that wasn't the case.

In the meantime, the following work has been carried out:

1. All the hose clamps, where some were obviously leaking diesel, have been replaced.
The diesel filter is new and causes almost no bubbles, and it looks very normal.
Replaced the filter valve on the top of the diesel filter with a clamp.
4. Replaced the overflow pipes at the nozzles with new ones.
5. Replaced the turbocharger (KKK, 0.2 bar pressure) with a new KKK turbocharger.
6. Ignition timing checked, OK.
7. Error memory, OK.

The car doesn't produce excessive smoke, even when fully accelerated, and not above 3500 RPM. As I said, I'm going to have a breakdown with this car; the turbocharger is new because I thought 0.2 bar of boost couldn't be the problem. The car drives exactly like it did before. It doesn't reach its optimal speed in any gear. Accelerating from 100 km/h to 120 km/h in 5th gear takes a minute.
Driving with the choke engaged doesn't improve the situation either.

I would really appreciate it if one of you could provide me with more information about it. After all, it's 'just' a TD and not a TDI.

Thank you very much!

Regards,
Dr.Cell

Hello Rainer K,

Thank you for your reply. The wastegate has two connections, correct? One goes to the left side of the engine bay and connects to a relay. The other goes from the wastegate to the turbocharger.

Why would someone have tampered with the ESP system beforehand? What could be the reason for that? The vehicle hasn't been modified or driven aggressively, nor has it been driven with any kind of performance modifications.
A perfectly normal diesel with 230,000 kilometers on the odometer.

Best regards,

Hi,

I deleted my previous post because I realized that the AAZ already has electronic throttle control. This places it in a generation of engines that I'm not familiar with.
If the engine control unit (ECU) displays that information in the measurement blocks, you might want to check the fuel injection amounts.

Best regards, Rainer.

Hmmm, the AAZ engine already has electronic throttle control? My former AAZ engine (1.9 TD; manufactured in May 1992 with 75 hp) definitely did NOT have electronic throttle control. It's been a few years, but the AAZ engine didn't have anything with an engine control unit. Or was that supposed to be introduced later...?

My friend's AAZ engine (1.9L, 75 hp) is from 1994 and also doesn't have electronic throttle or an engine control unit. Just for your information.

DrCell wrote:

Driving with the choke engaged also doesn't improve the situation.

I think it's clear that his car doesn't have an electronic throttle.

Enjoy your meal!

The AAZ engine does not have drive-by-wire throttle control; however, depending on the year of manufacture, it may have an "engine control unit."

The boost pressure should be approximately 0.7 bar, measured at full load while stationary with the throttle open.
He can't be reached, so let's head up a mountain and put the pedal to the metal in 3rd gear, boosting the turbo pressure.
It should ideally be in place by 2500, and preferably even sooner, by 2000.

If the wastegate has two connections, one goes to the pressure side of the turbo, and the other...
is controlled by a solenoid valve, and I believe (!) that the...
Vacuum pump.

Was macht das Magnetventil wenn Du es separat bestromst? Klick es? Does it turn on?
What happens if you disconnect one of the hoses connected to the wastegate?
What happens if both are missing?
If something improves, the error is likely located somewhere here.
If the boost pressure exceeds 0.7 bar, it's best to ease off the accelerator pedal; it can handle it continuously.
no.

You have at least one switch on the pump connected to the gas lever shaft; does it activate when...?
Are you giving it gas? Are the cables connected properly?
The switch is usually for the EGR system, but I believe (!) it controls something else on the newer models.
he also controls the turbocharger via the "control unit" so that it does not generate boost pressure under partial load and when the EGR system is active.
is being built.

Unfortunately, there are two instances of "glaub ich" in the text, and I'm unable to check it further because my AAZ is [problem/issue].
doesn't have something like that.

Removing the AGR (Abgasrückführung) system is illegal, but it can save fuel and protect the intake manifold.
obstructed.

And finally, something very simple:

Is the gas cable housing properly attached?
If the retaining clip is missing from the ESP, the housing will move when the accelerator is pressed.
and you can never go full throttle, let someone else do it and see what happens.
The lever on the pump was moved almost all the way to the stop.

Hi, Jockel.

Hello,
At AAZ, there is definitely no electronic throttle control. However, the latest models had an ESP system capable of self-diagnosis.

Here are some excerpts from Volkswagen:

Read error codes.

Workflow.

- Connect the V.A.G 1551 diagnostic tool and select the control unit for the diesel pump electronics (address 41); select it while the engine is idling.



Self-diagnosis.

Read measurement data block.
Currently, only display group 01 can be read out in the measurement block, and it provides the following values.

Advertisement.
Engine speed.
Funding duration.
Duty cycle valve for injection start.

If it doesn't have an electronic throttle, there's probably a bug in the system.
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.

@Dr.Cell: Could you please take a picture of the ESP?

Best regards, Rainer.

So,
I checked again.


The following components are activated in the specified order using the actuator diagnostics:

1. Exhaust gas recirculation (EGR) valve (N18).

2. Idle speed control valve (N177).
(only for air conditioning systems)

3. Glow plug indicator lamp (K29).

4. Glow plug relay (J52)

5. Valve for full load engagement (N194).
(Engine code: 1Y only)

6. Motor/Klimakompr. elektr. Connection.
(only for air conditioning systems)

7. Valve for injection timing (N108)

I would therefore say no to e-gas.

My question is, does he have an ESP?
Does he have AGR?
If so, I would check the EGR valve.

Hi,

I deleted my previous post because I realized that the AAZ already has electronic throttle control.

Greetings, Rainer

Hi Rainer, no, the AAZ engine in mine doesn't have electronic throttle control. It's the standard cable-operated type.


The boost pressure should be approximately 0.7 bar, measured at full load while idling with the throttle open.
He can't be reached, so let's head up a mountain and go full throttle in third gear, boosting the turbo pressure.
It should ideally be in place by 2500, and preferably even sooner, by 2000.
If the wastegate has two connections, one goes to the pressure side of the turbo and the other goes...
is controlled by a solenoid valve, and I believe (!) that the...
Vacuum pump.

Was macht das Magnetventil wenn Du es separat bestromst? Klick es? Does it turn on?
What happens if you disconnect one of the hoses from the wastegate?
What happens if both are missing?
If something improves, the error is likely located somewhere here.
If the boost pressure exceeds 0.7 bar, it's best to ease off the accelerator pedal, as it can't handle it continuously.
no.

You have at least one switch on the pump connected to the gas lever shaft; does it activate when you...?
Do you have gas? Are the cables there okay?
The switch is usually for the EGR system, but I believe (!) it controls something else on the newer models.
he also controls the turbocharger via the 'control unit' so that it does not produce any boost pressure under partial load and when the EGR system is active.
is being built.

Unfortunately, there are two instances of 'glaub ich' in the text, and I'm unable to check it further because my AAZ is

Thank you for the information, Jockel. I'll check right away to see which of these things I can answer.

Hi,

@Dr.Cell: Can you take a picture of the ESP?

I'd be happy to take a look at that tomorrow. Maybe you'll be able to see more details in the pictures than I can describe here. I'll post some pictures as soon as possible.

@everyone,

I have to say, the quick and competent help here is really good!
Best regards,

Rainer K. wrote:

If he doesn't have e-gas, there's probably a bug in it... 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. ... Greetings, Rainer

Enjoy your meal!

Yes, there's a mistake in it.

The pumps that golfschrauber1981 mentioned are the ones with the flow sensor.
between the high-pressure connections, where the sealing screw is normally located.
The pressure is regulated by the control unit, which receives signals from the FSS (Fuel Supply System) and other components.
adjusted by a solenoid valve.
It probably has nothing to do with Dr. Cells' problem.

Hi, Jockel.

Jockel wrote:

The pumps that golfschrauber1981 mentioned are the ones with the feed signal sensor located between the high-pressure connections, where the normally located closing screw for adjusting the start of injection is situated.

The pressure at the injector adjuster is adjusted by a solenoid valve, based on the signal from the FSS and the control unit.
Ah, another system explanation }.

Is this just a more sophisticated, speed-dependent injection timing control, or does it also take into account engine load, like in a TDI engine, for example, based on the position of the "throttle"?

Hello,

The descriptions of the MKBs have been corrected.

Best regards, Rainer.

Dr.Cell wrote:

In the meantime, the following work has been carried out: 1. All the hose clamps, where some were obviously leaking diesel, have been replaced. The diesel filter is new and causes almost no bubbles, and it looks very normal. Replaced the filter valve on the top of the diesel filter with a clamp. 4. Replaced the overflow pipes at the nozzles with new ones. 5. Replaced the turbocharger (KKK, 0.2 bar pressure) with a new KKK turbocharger. 6. Ignition timing checked, OK. 7. Error memory, OK. The car doesn't produce excessive smoke, even when fully accelerated, and not above 3500 RPM. As I said, I'm going to have a breakdown with this car; the turbocharger is new because I thought 0.2 bar of boost couldn't be the problem. The car drives exactly like it did before. It doesn't reach its optimal speed in any gear. Accelerating from 100 km/h to 120 km/h in 5th gear takes a minute. Driving with the choke engaged doesn't improve the situation either.

Hello,

What's the starting behavior when it's cold or warm? Do you have to crank it for a while, or does it start almost immediately? Does it puff out a cloud of smoke, or does it hesitantly rev up to idle speed? How is the idle (smooth or rough/stuttering)? Does it still pull poorly at low RPMs, or is it better there?

Verlier nicht den Mut, das ist vielleicht nur ne Kleinigkeit. We will find them.

Best regards, Uli.

Hello,

What's the starting behavior when it's cold or warm? Do you have to crank it for a while, or does it start almost immediately? Does it puff out a cloud of smoke, or does it hesitantly rev up to idle speed? How is the idle (smooth or rough/stuttering)? Does it still pull poorly at low RPMs, or is it better there?

Verlier nicht den Mut, das ist vielleicht nur ne Kleinigkeit. We will find them.

Best regards, Uli

Hello Uli,

I haven't been able to check the car for the issues mentioned today, but I'll probably be able to do it tomorrow. The car starts very well, the choke works perfectly, and it idles smoothly at approximately 950 RPM. Of course, when it's cold, it runs a bit unevenly without the choke. There's also no black or white smoke coming from the exhaust when starting. It pulls poorly both at low and high RPMs, practically at every speed, whether it's cold or warm. There's also no coolant leakage. The clamp for the throttle cable is also new, and it's not stuck anywhere. Additionally, the oil dipstick tube is also new.

I'll check the other things tomorrow, although I can't measure the boost pressure at the moment because I don't have a suitable gauge available.

Thank you all!

Best regards,