PostPolo: High Consumption and Jerky Performance

Hello.
I bought a Polo because I wanted a fuel-efficient car. Now I've discovered that it consumes around 6.7 liters per 100 kilometers even with very economical driving. It's not an SDI, just an SD. It has only 90,000 kilometers on the odometer.
'Additionally, the engine sometimes misfires when it's cold, but only at RPMs between 1500 and 2500, and only when maintaining a constant speed or accelerating slightly.'
Then I discovered air bubbles in the fuel line leading to the ESP (Electronic Stability Program). I suspected that this strange component related to fuel return was leaking at the fuel filter (it wasn't properly seated) -> replaced the filter -> it got a little better with the engine misfire, but it's still not fully seated, and air bubbles are still getting through.
Could it be that the strange connector that goes onto the filter also needs to be replaced?
And does the high fuel consumption have something to do with the jerking/stuttering?
When the engine is warm, it runs perfectly. Otherwise, it doesn't make much noise. Oh yeah, and the air filter has already been replaced.
Thank you in advance .

Okay, one more thing...
Could it be that the choke is constantly slightly engaged? While it's supposed to regulate the idle speed from cold to warm conditions, it's only just below the allowed 950 RPM when the engine is warm (according to the emissions test report, it's 947 RPM, but around 1000 RPM according to the speedometer). That would explain the increased fuel consumption.

Hi,

A Polo with 90,000 km on the odometer?

Morning: Cold start, full throttle, braking, engine off. Drop off/deliver letters/packages, start the engine, full throttle, drive 100 meters, engine off. Deliver letters/packages, start the engine, full throttle...

I wouldn't draw any conclusions about such a car based solely on the relatively low mileage of 90,000 km without thoroughly inspecting the engine – for example, does it consume oil?

Best regards,

January.

Now I've driven over 1000 km with it, and I checked again today... it's still completely full after the oil change I did 1000 km ago.
Okay, so this is a Polo from the late 90s. They all have mileage around 80,000 to 100,000 kilometers.
I don't think the engine is worn out. It runs very well once it's warmed up.

It's a shame that there isn't much information available about this 1.9D engine in the forum.
I'm interested in knowing how to configure the Lukas/CAV ESP. Or maybe it's internally leaking or something like that.

Just a side note: What's called "Shoke" is actually "Choke," and it doesn't exist in diesel engines. What looks like a choke in a gasoline engine is actually a "cold start accelerator" that adjusts the injection timing (not the fuel mixture to make it "richer," as with a gasoline engine).

What's the engine code for your car? What are the engine identification letters?

Maybe you can find something out with that.

m;

"Edit: My TDI from the late 90s already had over 120,000 km in 2002, and it was privately owned!! - so your "PostPolo" is definitely not going to be a long-distance vehicle - 'PoolHure' probably fits better."

As far as I know. Choke or cold start valve, it's all the same thing .

Be proud of your TDI. :-p However, mine doesn't consume any oil!!

Okay, help me out! Or rather, let's make some guesses.

Sure, no problem. Here's the translation:

'Thanks in advance.'

Quote:

Choke or cold start valve, it's all the same thing.

No one mentioned anything about a regulator.

Quote:

Be proud of your TDI. However, mine doesn't consume any oil!! :-p

Otherwise, I highly recommend this thread to you.
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.

When I mentioned the data about my cars, it was absolutely not about comparing brands with a "mine is better" attitude, but solely to describe the condition of your car.
I highly doubt that it was properly warmed up gently.

You have a problem and you're asking us for help, so please follow certain rules.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hello,

Andi84 wrote:

I bought a Polo because I wanted a fuel-efficient car. Now I've discovered that it consumes around 6.7 liters per 100 kilometers even with extremely economical driving. It's not an SDI, just an SD. It has only been driven about 90,000 kilometers.

"Diesel engines consume fuel. That's just the way it is. I once had a Golf 1, 1.6D engine. After adjusting the fuel injection, it ran quite well, but even with a 5-speed transmission, it still consumed between 6 and 6.5 liters per 100 km with my driving style. Later, I bought a Golf 2 TD with an intercooler, which consumes half a liter less under similar driving conditions, despite having double the horsepower and 150 kg more weight. Also, SDIs consume more fuel than TDIs, but your naturally aspirated swirl chamber engine simply cannot be a fuel-efficient marvel by its very design. However, it is cheap to acquire and much less (actually not at all ) prone to electrical problems."

Quote:

Furthermore, the engine sometimes sputters when it's cold, but only at RPMs between 1500 and 2500, and only when maintaining a constant speed or accelerating very gently.

This also happens with Bosch pumps, and I could tell you something about that, but when it comes to Lucas, I'm afraid I know nothing about it; as a mechanic, I'd say it's as foreign to me as the devil is to holy water .

Quote:

And is the high fuel consumption related to the jerking/stuttering?

Probably not. It's more likely that the shaking is related to air still entering.
My tip: sell that thing, look for something with a swirl chamber and a Bosch pump, convert it to run on vegetable oil, collect used frying oil, and fuel consumption will become a minor issue .

Best regards, Uli.

Sure, here's the translation:

'That's nice to hear, but according to other Polo drivers, the Polo should consume less fuel. What's more important to me is that everything on the car runs perfectly.'
Yesterday I found a puddle under the car. It wasn't motor oil, but rather dirty diesel fuel. I think it might be related to the fuel consumption and possibly air bubbles. But where should I look if not at the filter or the ESP? The engine is completely dry from the top.
Are there any known issues with fuel lines in Volkswagen vehicles?
Sure, here is the translation of the text from German to English:

'MFG' stands for 'Mit freundlichen Grüßen,' which translates to 'Sincerely' or 'Best regards' in English. It is a common way to end a formal letter or email.

Andi84 wrote:

...However, the fuel consumption, thanks to heating oil, is relatively unimportant to me. ...

I don't think you realize what you're doing to yourself!
Do you even know what the police or customs will do to you if they catch you? This ruins your record-breaking fuel-efficient driving for years, if not decades. Even if you were to start using regular diesel right now, they could still prove it after filling up many times. The heating oil dye is a pretty nasty thing; it sticks to you/the car almost forever .
And the chance of getting caught isn't actually that bad .

Just mentioning that in passing.

Heating oil.

Furthermore, I believe that the dye does not burn completely without leaving any residue.
It doesn't matter in the boiler; the dirt just falls out. But in the cylinder...

Furthermore, it's quite reckless to write something like that so openly. You wouldn't believe how non-anonymous people are on the internet, especially when they post in forums like this.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hi,

Hopefully, it is well known that tax evasion is a crime. Unfortunately, what's worse is that the public prosecutor's office *must* investigate crimes. There is unfortunately no room for discretion in this matter.
I hope that with the false statement 'I was using heating oil...' you were just trying to show off!

@dieselmartin: It doesn't matter in the boiler because the dirt just falls down, but in the cylinder...


Well, what do you think? Even inside a cylinder, the dirt initially falls to the bottom . The question is, what happens after that...? ---duck and run-----

Regards,
Sure, here is the translation of the text from German to English:

'Micha'

Hi,

Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.
I would ask you to refrain from making statements that constitute a criminal offense, for your own sake and to protect our host. Please remember that this is a public forum, and even customs officials and the police may be reading it!

2:
I only know the Lucas facility from the outside. I wouldn't go near it. As Ulli S. already mentioned, there's nothing worse.

3:
Some people I know who drive Post Polo cars with the CAV Lucas engine consume between 6.3 and 6.8 liters per 100 kilometers. So you're probably in that range.

4:
One of these CAV drivers put in a lot of effort and (money) to convert his system to Bosch, and now he uses approximately 1 liter less fuel while maintaining the same performance.

5:
It's possible that the sputtering is caused by air getting into the system. The source of the problem should be identifiable. Unfortunately, air often enters a system, but diesel doesn't. If there's a puddle of diesel under your car, you should be able to trace its origin from underneath.

6:
Sure, please provide the text you would like me to translate from German to English. I will focus on using accurate technical terminology to avoid misunderstandings.

Thank you.

P.S. At 90,000 km and with regular use as a delivery vehicle, I would recommend having the fuel injectors checked for their spray pattern.

Aside from the fact that burning heating oil in a vehicle is a crime, and that 90,000 km of postal service use corresponds to three times the normal usage, I would only switch to regular diesel to avoid committing crimes. Your heating oil likely won't create air bubbles at those temperatures, which would quickly turn into a thick sludge due to insufficient winter resistance.

Apart from that, heating oil simply doesn't meet the requirements that modern fuel injection systems demand.

Anyone who runs a TDI engine on heating oil risks damaging their fuel pump.

CU Gremlin.