Pump Damage: Ask the Pump Experts

Hello,
I converted my Golf 3 TDI to run on vegetable oil (using a two-tank system, a coolant recirculation system, and an A8 turbo).

After switching to a different type of filter (Pöl), the ESP (Electrostatic Precipitator) started leaking and was no longer functioning properly.
Since 'clear' is normal, I completely sealed it.

After approximately 4000 km, the solenoid valve of the ESP's spray adjuster failed.
Consequences:
- no performance
- extreme nail polish
- Error code in the engine control unit (ECU).

Now, my question is:

Can a spontaneously failing solenoid valve be caused by an increased ESP temperature? Does anyone happen to have a similar valve or a defective ESP unit?




P.S.
It can be replaced relatively easily, even when it's already installed.
- Release the lines.
- Completely dissolve the ESP.
- Loosen the rear mounting plate from the high-pressure part.
- Tilt the pump.
- Remove the valve.
-......

'I had a whole 2.5 hours to spare, anyway, I didn't have anything better to do.'

HM ??

Perhaps you made a mistake while printing (didn't work cleanly), causing the nozzle to become clogged.

Do you have any photos of the event?

Wo ist dein 2. Tank?

Do you always drive 100% after the warm-up period?

Currently, I have 20% of my fuel tank filled with Poel fuel, and so far, it has been working without any issues.

And consider a two-tank blending system: A PWM-modulated valve mixes any desired amount of biofuel with diesel "on the fly." I'm just afraid of using 100% biofuel.

Are your nozzles still the original ones?

Greetings.
m;

Did you perhaps make a mistake (work carelessly) while applying the sealant, so that the nozzle became clogged?

Definitely no. The spray nozzle restrictor works perfectly fine with the solenoid valve from my spare pump.

Wo ist dein 2. Tank ?
The tank is located in the spare tire well (27 liters, stainless steel).

Do you then drive 100% after the warm-up period?
Yes, it's about 3-5 kilometers.

Are your nozzles still the original ones?
No, those are AFN injectors with approximately 100,000 kilometers (or 62,000 miles) of mileage.

Unfortunately, I don't have any photos of that event; I was really frustrated with that vehicle.

@golfschrauber
How warm is your preheater before the ESP? What kind of damage did the solenoid valve have? How do you preheat it, perhaps with a glow plug directly in the preheater?

@dieselmartin
1Z and at temperatures 20%? Add 50% and the engine runs. What might happen are the seals of the ESP. I've experienced this several times, where they become leaky. Your PWM mixing won't work very well like that. You need a mixing vessel where you 'prepare' the diesel. And from there, it goes to the ESP. It's quite complicated. Pre-pump for oil, pre-pump for diesel, mixing vessel with level control, if it's going to be done properly...! Many others have had this idea. The most practical approach has proven to be this intermediate step via the mixing vessel. Ultimately, I would go directly to 2 tanks and 100% (the effort is the same), and if you do it properly, nothing will happen. Always preheat and then switch. And don't forget to flush and switch back to diesel if you're standing still for a long time (traffic jam, etc.).

@ Golf enthusiast/tinkerer.

I didn't express myself clearly.

The injector nozzle and its solenoid valve are two different things. The injector nozzle is likely fine, because if it's stuck, you can probably just replace the pump.

The valve could potentially seize up mechanically, in addition to an electrical defect (e.g., a burnt-out coil). Even though a magnetic field and thus force are generated on the piston, it doesn't move because it's stuck.


@ lappen
I thought that the wing-cell pump in the ESP, acting as a volumetric pump, would deliver the mixture even without a mixing vessel and two pre-feed pumps, and that the volumetric ratio would precisely match the switching times of the 2/3-way valve.

m;

So, the oil temperature before ESP is hot , I have no idea how many degrees.

Using an A8 coolant heat exchanger.

The solenoid coil in the solenoid valve is burned out (the resistance was infinite).

@dieselmartin

Yes and no... there are problems... you can imagine. Having a two-tank system would solve a lot of those issues!


@golfschrauber

Is it just an A8 WT connected to the cooling system? If so, that's not necessarily a good thing, because the oil temperature can reach 90 degrees very quickly, which is actually too high. The optimal range is 70-80 degrees max. We have a controlled cooling system. Anything above 80 degrees in the cooling system opens it. When the temperature reaches 70 degrees in the cooling system, it closes again. However, I can't and won't believe that the solenoid valve 'burned out' due to the oil temperature.

The N108 valve (that's what it's called in VW terminology) on my ex-girlfriend's car (year 2000, 93,000 km) also failed.

And it has always been operated using diesel fuel.

I think it's more likely that "this can happen sometimes."

m;

Especially when it comes to mileage...

Hi Dieselmartin, long time no see!

Since the term 'AKU' came up, I feel compelled to add my two cents.

After the spectacular injector nozzle stuck at 93,000 km, and a miraculous self-repair after 5,000 km using a Pöl-RME mixture, I have now reached a mileage of 127,000 km, which means approximately 35,000 km using the Pöl/RME mixture.

It remains completely inexplicable and contradicts all sorts of rumors and common textbook opinions.

The only downside is an increasingly leaky ESP (Electronic Stability Program) system. During the last oil change, the foam mat in the plastic tray under the engine compartment was so saturated and deteriorated that it disintegrated into its individual pieces. However, it hasn't leaked onto the road yet.

Now, let's hope that the leak remains within tolerable limits for a long time (fortunately, oil/RME thickens quickly in fresh air and turns into a honey-like substance, so it doesn't drip as quickly).

The N108 (that's what they call the valve in VW jargon) on my ex-girlfriend's car (year 2000, 93,000 km) also failed.

off topic: I hope that your ex (who you mention quite often) has found someone new by now . I think you definitely deserved it .

hello
Holger.