Broken Everything? Troubleshooting Guide.

Hello everyone, I'm new here. I've spent half the day reading technical articles, learned a lot, but haven't been able to connect much of it to my car...

Here's a little background:

I drive a Passat 3B TDI, manufactured in 1998, with a 1.9L TDI engine (90 hp). The engine code is AHU. I've owned the car since January, and the previous owner had installed a 'tuning box,' which I decided to leave in for the winter with the intention of removing it in the spring.

In May, I started thinking about getting a 'proper' chip to achieve my performance goals in the most engine-friendly way! Discouraged by various offers from different companies, ranging from Digitec to garage tuners, I considered the idea of first 'revving up' the existing 'fake' chip before getting rid of it...

I did what I was told and turned the potentiometer from approximately the middle position to about 3/4, just to see what would happen! I then drove a distance of almost 1 kilometer. The acceleration was really good, and then, just outside the town, I revved the engine in the second gear up to 3,800 RPM, when there was a sudden loss of power: the engine seemed to 'cut out,' but it kept running, although I lifted my foot off the accelerator! For the remaining 200 meters, I didn't see anything in the rearview mirror . After that, I turned the potentiometer back down...

My initial amateur diagnosis was straightforward: too much diesel being injected, which wasn't igniting... The problem with that: ever since, the car has been constantly producing black smoke, especially when starting up and running for a short time (like a chimney).

'The P-box is now installed, and a 30 HP chip from In-Motion-Tuning has been fitted (carefully soldered in), but I haven't noticed much of a difference. It's still producing black smoke! After a faulty valve cover gasket that caused oil loss of nearly half a liter every 500 km, I've been going from one mechanic to another, and from one VW dealer to another, since the beginning of June.'

In the meantime, the LMM (mass airflow sensor) has been replaced, the turbocharger has been checked (no oil in the coolant!!!), the intercooler system has been checked for leaks, the engine control unit has been temporarily replaced, the fuel injection pump's start of injection has been checked, and much more. The result is: the car is still producing excessive soot! According to the workshop, the last resort for troubleshooting would be to replace the fuel injection pump, but this cannot be done as a test. Otherwise, we are all, including me, stuck in the 'valley of the clueless' .

'The car definitely lacks power. It mainly produces black smoke at lower RPMs under load (it's worst when driving uphill in a 30 km/h zone..., but I don't see anything on the highway...). And recently, I've been experiencing a 'jerky start' (it doesn't accelerate, it just jerks), but only occasionally!'

Could it really be the pump? Could it have something to do with the sports exhaust system?

I am grateful for any advice!


Best regards,

whitelife

Hello,

What does the error memory say?

Best regards, Rainer.

Is the AGR defective or defective®?

CU Gremlin.

Fuel injectors?

The error memory is empty! However, the fuel injectors have not been checked!

...but could the carbon buildup really be caused by the fuel injectors?


You're welcome.

whitelife[/u]

The AGR (Automatic Gearbox) was checked and, for reasons I can't comprehend, it was full of silicone. However, it has been cleaned out, and theoretically, it should be working again.

Best regards,

whitelife

whitelife wrote:

...but could it really be the injectors causing the problem?

Okay, I'm ready. Please provide the German text you want me to translate.

Bertil wrote:

whitelife wrote: ...but could the problem really be related to the fuel injectors? /viewtopic.php?t=6361

Well, whether that's comparable .

In the link, the nozzles were "tampered with."
But here, the engine has been misfiring since a test drive with a power box, and nothing has been done to the injectors.

What I can imagine is a burst "suction" hose or a slipped clamp, etc., caused by excessive boost pressure during the dyno run - if the control system could no longer regulate the pressure due to the increased load on the turbocharger.
The symptoms described in the first post, in my opinion, at least suggest the latter assumption.

@Whitelife
-> Check all thick, raw hoses and tubes between the turbocharger and the intake manifold for external oil leaks – this is a classic indicator of a leak.

If you've noticed any new noises coming from the engine compartment since the oil change, especially when the engine is under load (such as a hissing, whistling, or whistling sound), that confirms my suspicion.
If not, I would still check it.

ulf wrote:

Bertil wrote: whitelife wrote: ...but could it really be related to the injectors? /viewtopic.php?t=6361 Well, whether that's comparable

.

I was only asking about the fundamental question of whether russeting can be caused by nozzles, and the answer to that is clearly: YES!
I didn't want to interpret anything further from the link.

And if a piece of debris has come loose (which could have happened even without the engine running) and is lodged across a nozzle, preventing it from closing properly, then it will cause excessive smoke.

Bertil wrote:

My question was only about the fundamental issue of whether russeting can be caused by the nozzles, and the answer to that is clearly: YES! I didn't want to interpret anything further from the link.

Ohhhhh...

First of all, thank you very much! I think it's great...

I have an oil leak on the hose, right from the pump towards the cooling system. The great workshop said it's still sealed, but I'm going to replace it.

No matter the cost: the 'Drecksschleuder' must be able to run normally again .

Can I test the nozzles somehow? And a new set costs a lot of money, right?!?!

So far,

whitelife

whitelife wrote:

Is there a way I can test the nozzles?

Yes, at a reputable workshop with a diesel department (or a Bosch service center) that can assess the spray pattern of the injectors.
For information regarding the nozzles:
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.

Quote:

And a new sentence costs a lot of money, or does it?!?!?!

So, they definitely won't take