Funny starting problems

Yes, I used the search function. Yes, there are things that are similar, but not exactly what I'm looking for.

Okay, here's the translation:

'I have an A4 Avant, model year 1998, with an AFN engine here. This car belongs to the boss of my wife. The problem with the car is quite mysterious: it doesn't start, either when cold or warm. It just cranks and cranks. If you spray starting fluid into the intake, it starts right up, runs smoothly, doesn't smoke, and doesn't lose power even at higher speeds. If you turn it off when it's warm, it starts immediately and runs fine... There are no error codes stored. When it's running and at operating temperature, the fuel injection timing is slightly advanced. Loosening the glow plug connectors reveals excessive diesel fuel. The fuel injector pump (DDI) can't be the problem, as I've already bypassed it. However, if you connect a glow plug directly to the high-pressure line so that the injector sprays freely, you don't see any spray at all. The conclusion is...''p im ar...? (meaning: at the starter speed, the pressure built up by the high-pressure component is not sufficient to open the injector nozzle).'

'Does anyone have any other ideas? I honestly can't believe that the ESP system is broken after only 70,000 km. It started with the engine being difficult to start when cold, and the problem is increasingly occurring even when starting the engine when it's warm.'

Hi Jörg,

I mean that I've read about a very similar problem here before, and in that case, the ESP (Electronic Stability Program) also ended up being faulty.

How do you find the top dead center (TDC) on a longitudinally mounted engine? Is there also an opening, like on a transversely mounted engine (e.g., a clutch bell), where you have a clear view? Audi models specifically!

Okay, regarding the idle speed, as I logged it, it was around 270 RPM, and possibly even higher.

Hmm, 270 RPM seems very low to keep the AFN running. I need to check if I can find anything useful about the OT marking in a reference book.

Hm, 270 Upm seems very low to keep the AFN running.

Me too. 300U/min is the lower sound limit!

'Try jump-starting it from another running car to provide 14V and see if the starter motor speed increases.' It's either the starter or the battery.

Julian wrote:

300U/min is the lower limit for audible sound! "Try jump-starting it from another running car to provide 14V and see if the starter motor speed increases." Either it's the starter or the battery.

Let's try this: rolling up to 30 km/h in 5th gear was always enough to get the AFN Golf started.

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

Okay, it's not the battery. I've already tried putting a brand new battery from my old A4 into it, and it's the same problem. My A4 also runs in that range and starts without any issues.

Even if the crankshaft speed is a bit too low, shouldn't at least something be coming out of the injectors? What's also funny is: it doesn't seem to have any loss of power. But that's just an illusion! When you encounter a hill, you suddenly notice the lack of power, it starts to jerk above 3500 rpm, and then it throws the 'fuel injection start regulation difference' error. I've already replaced the crankshaft position sensor, but it's the same problem. I can't help but feel that the defective ESP is getting closer...

joergs wrote:

How do you find the top dead center (TDC) on a longitudinally mounted engine?

Yes, for example, in the 1Z B4, there's a hole in the clutch bell on the left side. It's impossible to miss.

Okay, quick update:

'The starter motor is definitely going to be replaced. It's been having intermittent single-cylinder issues and sounds bad (like an organ) now. I've already removed most of it. I can't get the top screw loose. There's no room from below because the catalytic converter is in the way, and I don't have enough leverage from above. A wrench extension doesn't help either, because the extension hits the intake manifold... Is there a trick to getting it off?'

After opening the clutch bell, I searched everywhere, but I couldn't find anything.

Okay, just so you know: while it's technically possible to start it by rolling, it takes a while for it to actually start. This applies whether the engine is warm or cold. Starting fluid helps it start faster...

Hi!
I once had similar symptoms with my AHF (presumably a heating system). At least when it came to demanding heat output, it usually resulted in jerky operation and the error message "Injection start - control difference." Ultimately, after an initial attempt to start, he could only rely on the emergency system, and he was unable to recover from that.
In the end, even the "old" ESP had to be replaced (120,000 km ).

The problem, as can be seen below, was the fuel injector control valve. You could try removing the cover on the ESP and see if anything is broken. I was actually able to find these crumbs throughout the entire ESP (I took it apart out of curiosity). Perhaps these small metal pieces are causing the starting problems, or maybe they are clogging some of the pressure lines.

Best regards.

[img][/img]http://img80.exs.cx/img80/6559/ESP.jpg{MARKER}

Okay, let's go:

The starter motor has been installed since just before noon, and it's making a 'ötelötelötelötel' sound instead of a 'brummmmmmm' sound.
Just in case, I ordered a brand new ESP from Boschens yesterday. I installed it, and the engine started right up. It's not amazing, but it starts after 5-7 seconds of cranking. The injection timing seems to be correct. According to VAG-COM, it's exactly on the zero line. The timing also seems to be perfectly matched. I also installed the relatively new injectors from my old A4 to test. With those, it doesn't start significantly better either. This whole situation made me very concerned, so I had the compression checked. And bingo: 2 cylinders are below the wear limit. That made me suspicious, so I contacted the person who sold it to me. He's had the car since January and bought it used. So, we went through the history of the 3 previous owners.The previous owner claimed the car had around 300,000 km on the odometer. Unfortunately, the dealer (a small used car lot somewhere in Hesse - the vehicle was listed on mobile.de) no longer exists. So, the guy won't have many options if he wants a working car: a replacement engine. I wonder if that's even feasible. Does anyone have a rough idea of how much that would cost? I'll call a few repair shops tomorrow...

Okay, if a 'new' engine were to be installed, then perhaps one could use something that meets Euro 3 standards, right? What engine options were available from Audi in the 110 horsepower range that met those standards?

joergs wrote:

2 cylinders are below the wear limit. ?

Hm, that's annoying enough .

But on this occasion, you might consider having a nail sample taken for the "hop test" - if the "official result" is already known.

I suspect that significant time differences will also be observed.

Even if the measured differences are relatively small, such that 2 cylinders are barely below the limit and the others are similarly close above it, the "magnifying effect" of the extremely low speed during the hop test could still produce a noticeable result, in my opinion.

If not, the story will quickly and painlessly disappear from the list of used car tips.

I had completely forgotten about the hopping test! That might have put me back on the right track...
It arrived as described. The cylinders with lower compression have a significantly shorter time interval.

I have to return the car this afternoon until a suitable replacement engine is found.

joergs wrote:

I had completely forgotten about the hopping test! It might have put me back on the right track... It is as described. The cylinders with lower compression have a significantly smaller time interval......

Aha
Can you provide some order-of-magnitude differences in hopping (in seconds or time ratios) and the measured compression, to get a rough idea of the "resolution" of the hopping test?

6.5 - 5.3 - 5.4 - 6.7 seconds.

It makes about a 15% difference... not a lot, but it's there.

'However, what makes me suspicious is this: if it has low compression in two cylinders, shouldn't there be diesel fuel leaking into the oil, which would increase the oil level, especially at lower engine loads? But during the oil change after 12,000 km, I didn't notice anything unusual, neither in terms of smell nor oil level.'

joergs wrote:

6.5-5.3-5.4-6.7 seconds

Wow, stopped at the 10th .
I've only been doing it by counting "21, 22,...".

Even though I might be bothering you, I would still be interested in seeing the corresponding compression measurement values.

Quote:

what makes me suspicious, however: if he has too little compression in 2 cylinders, then he should have diesel fuel entering the oil, which would increase the oil level, especially at lower loads.

However, during the oil change after 12,000 km, I didn't notice anything.
Do you mean playing the organ?

If it's running, the diesel engine burns fuel (approximately) as much as with normal compression -> why / how should unburned fuel reach the running surfaces to be flushed into the oil from there?

Or what other ways are there for oil to get into the combustion chamber of a V-twin engine?

Or does he also experience complete breakdowns while driving?