VW T3 AFN (Chip) -> Excessive smoke, reduced power, rough engine running

Hello everyone,

I have already been able to understand the symptoms mentioned in the title, along with their analysis and solutions, using the search function, and I will be checking them this weekend.

Unfortunately, I'm not entirely clear on the extent to which a rough engine running (NOT knocking) is related to this. It doesn't quite seem to fit together, because if the charging circuit has a leak, wouldn't the engine necessarily run more roughly?

My car's problems started when I drove my van on a trip, pulling a trailer (loaded with two motorcycles) and carrying a lot of luggage, over the mountains. Since that trip, it's been producing a lot of black smoke, has slightly less power, and the engine runs roughly (across all RPM ranges). It's also strange that it's now starting to get hotter than usual when running at full load, especially after the vacation.

Normal acceleration; Reaches top speed; Oil consumption: 0.5L per 5000km.

Could the problem be with the nozzles?
If the cause of the problem is likely to be with the injectors, I will remove them this weekend and have them inspected.

Thank you in advance for any help you can provide. Tips...

Best regards,

Gunnar.

Is it still a good time to start the vaccination?
Is it adjustable via the EDC (-> basic settings in block 004 set it to maximum early, including displaying the values; basic settings in 000 set it to maximum late for checking the pump timing)?

Perhaps the pump is malfunctioning, or the fuel injection start control valve (N108)) is broken.

m;

Hello everyone,

I have fixed the problem with the black smoke and the loss of power. Apparently, the linkage from the vacuum sensor was slightly stuck. Now it's working again ... As the bus was being lifted onto the stage, the discoloration of the metal revealed that the heating system in the loading area was probably used quite frequently to keep things nice and warm.

I think I should probably remove and verschandeln the charging unit sometime in the future, so the rods don't get stuck again.

BUT:

The engine still runs roughly. This is most noticeable when the engine is idling. It's heading in the direction of 'nailing' it...

According to the TDI timing, the pump is likely misaligned (it's right on the lower limit). However, I've been aware of this issue/condition for about a year now, although it hasn't been accompanied by the rough engine running.

Are we really just left with the nozzles?

Best regards,

Gunnar.

PS: Thanks for the tips.

First, set up the pump, and then you can still deal with the nozzles .

m;

t3_tdi wrote:

I have fixed the problem with the black smoke and the loss of power. Apparently, the linkage from the vacuum diaphragm was slightly stuck. Now he's pushing again

.
Hmm, in theory, a TDI engine shouldn't start producing excessive soot if there's a lack of boost pressure, because the "fuel injection map" is designed to compensate for that.

If the engine, through tuning, "releases more diesel than there is air" (stoichiometric ratio = 1:14), then a TDI engine can, of course, also become a "black smoke emitter" during acceleration or due to insufficient turbo boost .

I've already seen something like that in a tuning file from a well-known tuner.

Okay, so... after my attempt to fix the loader adjustment didn't last long, I just installed a rebuilt loader. Now it's working again; this time, completely without black smoke. The new loader even has a large vacuum chamber on it.

At the same time, I had my injectors cleaned and tested at a Bosch service center. Result:

Nozzle 1 -> defective; clogged.
Nozzle 2 -> OK.
Nozzle 3 -> OK.
Nozzle 4 -> defective; clogged.

For all nozzles, the actual opening pressure is 5 bar lower than the target opening pressure.

I cannot assess to what extent the low opening pressure is currently critical, although I consider the error to be rather minor.

Is it possible that the increased soot formation in the combustion chamber, caused by the faulty fuel injector, contributes to the fuel injectors themselves becoming 'fouled' more easily? Alternatively, if that's the case, is it conceivable that a clogged nozzle could 'recover' after a valve replacement?

Well... in the next few days, the ESP (Electronic Stability Program) will definitely still be adjusted.

See you then... Best regards, Gunnar.

The Bosch service can only measure the first stage, which is 190 bar.

And based on my gut feeling, I'd say 185 bar is still acceptable.

What does "defekt, verrusst" mean? How "defective" is the nozzle?
Are there any vacancies?

m;

Unfortunately, I didn't receive any other information from the Bosch service. He simply stated that nozzles 1 and 4 are defective (due to being clogged).

I can imagine that some of the nozzles might be clogged. I wasn't informed about the extent to which the nozzles are still usable (or unusable)...

I reinstalled the parts for now, as some new nozzles are currently too expensive for me.

We once did a fun, old-school test by loosening the fuel injection lines one by one while the engine was running. For all four nozzles, the idle speed reduction was identical, or no difference could be detected.

Best regards, Gunnar.

Hi Gunnar.

If the timing is already at its lowest limit (meaning ignition starts too early --> rougher engine running), then an injector that opens too early, even if only slightly, will only exacerbate the problem. This can certainly lead to a noticeably rougher engine running.

Gunnar,

allow me to ask a question in the meantime:

Which gearbox are you using in your T3 with a chipped AFN engine?

I sometimes do some off-roading in the JX with a colleague using a trailer with a 3-horsepower engine, but as far as I know, that 3-horsepower engine starts to struggle around 200 Nm of torque.
Furthermore, it's so short that, according to... Operating instructions can also be accessed at the same level, even when approaching it for the second time.
That probably explains the clever circuit diagram with the mirrored pathways.

m;

Here's something else about the Deuses. My BOSCH representative once offered me a new internal component for 80 euros per injector.

Hello everyone,

I would like to have my AHF (manufactured in 9) tuned after I install my G50/03. However, I'm not sure whether to have it chipped or tuned via OBD. Can anyone recommend a good place or service?

I haven't had any success searching here so far because everyone seems to only be doing PD tuning.

By the way, the G50 transmission with a different 5-speed configuration is the one that most closely resembles the original TDI gear ratios, and also in terms of durability. Everything else, in my opinion, doesn't make much sense.

Above 4000 RPM, the torque on the TDI engine drops significantly, which is why it struggles and loses power when going uphill at 140 km/h.

Best, Mike.

Hello dieselmartin,

I had my transmission (formerly 3H) rebuilt... with a 4.14 axle and a long 5th gear (0.7). To increase the torsional strength, I had South African oil deflectors installed in my transmission.

The 4.14 axle was never offered by VW and, to my knowledge, is a custom-made product that you can obtain from companies like HA-Projekt or Bernd Jäger.



I believe my gearbox is now optimally tuned for the AFN.

Best regards,

PS: Come to the bus meeting in Hockenheim, there will be tons of modified buses to see.http://www.ha-projekt.de{MARKER}