Nozzles: Should You Be Concerned? (Image)

Hello.

TDI ALH engine with VP 37 injection pump, injectors set to 220 bar. Injectors are new, with 4000 km mileage. Of that, 1500 km were driven with a mixture of 75% rapeseed oil (cold-pressed) and 25% biodiesel. The vehicle has a dual tank system with a closed return line and a VW water/oil separator.

I removed the fourth injector for inspection. Should I be concerned about deposits affecting the spray pattern? Should I increase the diesel content or adjust anything else?

Regards,

Paul.
http://www.polo2f.privat.t-online.de/Duse.jpg

Hi,

In your pictures, you can't really see the spray pattern .
Since the holes appear to be "open," I would rather say "no."
Just try cleaning the nozzles; it's just guesswork otherwise.

Best regards, Rainer.
PS: Adjusting the injection start and pressure via software modification is not a problem; just ask.

What do the nozzles look like when you only use diesel fuel? Do they look roughly the same, or do they remain metallic and shiny?

Hi,

No, they are not mechanically clean. If the nozzles and the engine are okay, there is a thin layer of gray-black soot on them.
The more incomplete the combustion (due to a worn engine or faulty injectors), the more likely the tip will resemble a piece of coal briquette.

After only 4000 km, I find the flaky layer on your nozzles to be a bit too thick already, and it's already showing cracks. It looks more like burnt "food" on a ceramic cooktop in a single-person apartment rather than "soot."

Best regards, Rainer.

Currently, the question is whether to continue using the 'Pöl' or to stop. If I use the 'Pöl' less than 50% of the time, the effort involved isn't worth it.

I will put the nozzles in the ultrasonic cleaner tomorrow until the tips are clean. Then I will run two tanks of fuel with a 50% mixture and see how it goes from there.

Good evening.

What is your driving profile like? Do you mean that 75% of your driving is done using 'Pöl,' or do you mean that only 75% of the 'Pöl' is in the tank? What is the purpose of having two tanks ?

For 4,000 km, I find your 'scarred' injectors to be a bit concerning. I run a mixed fuel blend in a single tank and took them out after about 6,000 km. The injectors only had minimal deposits (except for the hole that the glow plug touches, which had a bit more), but they were easily cleaned out with a fingernail.

I have a mixture of heating oil and diesel in the second tank, with 75% heating oil and the rest being diesel. The normal tank contains only diesel.

For the 1500 km trip, I can roughly divide the distances as follows: 500 km on the highway at a constant speed of 120 km/h. 400 km on the highway with a mixed speed range of 130-160 km/h. 300 km on the highway at a constant speed of 160 km/h. The remaining distance consists of country roads and a bit of city driving.

I only turn on the heated seat when the engine oil reaches 70 degrees Celsius.

You should have seen mine after 200 km in Switzerland, driving at 50-60 km/h with a 50% mixture of biodiesel. I ended up replacing them because they started acting like steam engines, even under partial load and with 100% diesel.

Around each injection site, there was a small bump, almost 1mm high, with a crater on top. It couldn't be removed with a fingernail.

HI.

You can find the fuel consumption data for my (1-tank) Poel blend on Spritmonitor.

When I rebuilt the injectors, the old ones didn't have any deposits other than the ones Rainer mentioned. Everything could be wiped clean.

m;

How much are you mixing in? Have you modified anything, such as pre-heating, fuel mapping, or fuel injection pressure?

Mix occasionally.

Last October, while driving on the highway with a warm engine, I ran out of gasoline and had about 3% left. However, before the engine cooled down, I refilled the tank with diesel.

Otherwise, I don't exceed 50%, because I have an extreme driving profile.
During the week, I commute 5km to work and 5km back.
Over the weekend, the distance traveled will be between 150 and 250 kilometers.

Conversion: None (except for the isolator pipe and the AFN cover).
I can take photos during my lunch break.

m;

@ Paul

I've adjusted the title because there's no spray painting visible .

m;

I probably should have mentioned that I ended up getting a flat tire back then, and that the roads in Switzerland are definitely not suitable for driving on narrow tires (the toll sticker for the autobahn was too expensive for me at 34 euros).

Hi.

If I drive less than 50% on public roads, the effort is not worth it.
With a 2-tank system, definitely not. If you drive with a single tank, you can save yourself the extra tank and Sirais, then it's more worthwhile. The effort would be the same, since you're still mixing diesel with the fuel anyway. Just a tip .

Currently, I use approximately 55% rapeseed oil and around 30% in the winter (always mixed with a bit of gasoline). I haven't experienced any problems so far, and there hasn't been any increase in oil consumption. This is despite my usual driving pattern, which doesn't primarily involve long distances (approximately 2 x 25 km per day - highway/country road/city).

500 km of highway at a constant speed of 120 km/h. 400 km of highway with a mix of speeds from 130-160 km/h. 300 km of highway at a constant speed of 160 km/h. The rest is country roads and a little bit of city traffic.
The nozzles look quite severe, but as long as you don't have significant deposits around the holes, I wouldn't worry. Do you also use fuel additives in the city? Is the AGR (Exhaust Gas Recirculation) system broken? In my opinion, this crust comes from incomplete fuel combustion. Or what do the nozzle specialists think about it .

I already have two tank systems installed. I mostly use it on country roads and highways, hardly ever in the city.

AGR is blocked. An exhaust gas temperature sensor is now located in that position.

@dieselmartin: So, I tipped it over after the engine was already warm, and then I drove it for about 97% of the distance.

How did you deal with the suction problem back then, considering the original (thin) hoses? Did the injection restrictor even reach its maximum limit (error message)?