Short Buy Strategy: Is It Working for You?

http://www.big-game.de/images/grafik.jpg

This photo shows that the fuel temperature is too low. However, I have also seen readings with:
Too early for SB.
The plot is outside the display area.
etc...

My mechanic thinks there's a missing signal! He says only one point is being displayed on the graph (110-120).
Since he already had the vehicle 'in a state of disrepair,' the only remaining problem for him is the pump.

What are your thoughts on that?
What signal might be missing? Did I perhaps wire something incorrectly?

Otherwise, the bus runs reasonably well (missing low-level catalytic converter) – it just struggles to start; it takes about two attempts before the starter motor almost gives up... then it eventually starts, and of course, there's definitely a lot of unburnt diesel being emitted. I'm always waiting for the fire department because of the smoke. Once the engine is warm, it starts well.
So, I'm actually assuming that the injection started incorrectly.
I can't see anything on the graph, or should I just try turning the pump?
How was it again? Counter-clockwise early - with late - or the other way around?

My main concern is to find out if the problem could be caused by a missing signal. If that's the case, I might need to re-check the electrical wiring in that area.

It shows a start of spraying at 0 (zero).

Have you checked for any error codes?

Is the NBF recognized as defective or not?

If there are no codes present, the pump may be completely misconfigured...

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

If you already have a VAG-COM diagnostic tool, simply read the fuel temperature value; that will tell you if this is the problem. It's possible that the sensor itself or its electrical connection is faulty.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

'NBF will definitely be recognized (if it's removed, there will be an error; otherwise, no error).'

As mentioned, various error messages are displayed - the image is just an example!

The only error codes that are listed are:
17978 - After 2 x 40 seconds of beeping, the battery voltage is likely low.
and... I don't know the number... V-signal is missing.

Fuel temperature is displayed and changes depending on the operating mode or duration.
Remains within the previously defined target values[/b].

wurbel wrote:

This photo shows that the fuel temperature is too low. However, I have also had readings with: Too early for SB. The plot is outside the display area, etc...

Right on the X-axis, there seems to be a noticeable fluctuation around 110/120. If that's related to the fuel pump setting, I would check the infamous KW screw of the 1Z engine – just to rule out any potential for expensive damage.

Based on my experience with the AFN system, a "too low" fuel temperature only slightly shifts the graph value.

The KW screw has been tested.
I've actually checked everything possible multiple times, or had it checked by others.

As mentioned before, it's not so much about 'the' specific image – I just always had a similar display. The 'flying speck' shifts along the axis depending on the fuel temperature, but that couldn't have been it!

It seems I'm missing the corresponding element on the Y-axis.

dieselmartin wrote:

It shows a spray start at 0 (zero).

That's not quite right; the scale starts at 10.

Have you ever tried adjusting the focus ring (SB)? It looks like it's simply set too far off.

wurbel wrote:

The "flying shot" mechanism shifts along the axis depending on the fuel temperature - but that couldn't have been it!

That means the start of the injection is detected, but it's happening too late compared to the desired setting.

"Take the car for a test drive with a wide load range (comfortable cruising at low RPMs up to full throttle acceleration in 3rd gear, approximately 1300 - 4500 rpm) and check if and when the SV (throttle valve) duty cycle reaches its maximum limit."

wolfi_b wrote:

dieselmartin wrote: It shows a spray start at 0 (zero). That's not quite right; the scale starts at 10. Have you ever tried adjusting the SB?

It looks like the SB is simply misaligned. }

That's completely wrong.

Below, in the two boxes, the current values are displayed: Diesel 115 SB 0.

The graphic is probably slightly incorrect because it assigns a value of 10 to everything less than 10.

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

Okay, you're winning 1-0.

Hi,

Please put a checkmark next to "> 80°C = ok".

Best regards, Rainer.

So, I think the timing of the fuel pump is way off, which is probably why it's starting so poorly.
Could you please turn it towards the early morning direction?
That's why the start date for funding is set to 0.
Perhaps the pump is just a little bit off.

Well, a whole tooth...
but it's also possible that he jumped sideways because he landed on two teeth instead of all four...

@ulf
Okay, I will.

well, a whole tooth...
but it's also possible that he jumped sideways because he landed on two teeth instead of all four...



2 teeth off? I think that's a rumor that he can even start with a somewhat normally positioned distributor. Even being 1 tooth off is enough, and then nothing happens. With Startpilot, it does start, but it doesn't take any fuel and smokes terribly and shakes violently! Can you believe it!

Well, look at that – it works!

So, just one tooth out of alignment would be enough to keep the engine running, but barely.

Conclusion: My engine isn't misaligned by even a single tooth, because it's actually running quite well.

However, I can't really estimate the performance because the engine is in a T3 bus, and I haven't had any other TDI vehicles before.

I'll try to enable logging tomorrow and post the logs here.

Hello? These are the timing specifications. While the injection start is dependent on the timing, if everything else is okay with you (e.g., crankshaft position sensor), it can be completely misaligned. Even if the timing, meaning the position of the camshaft relative to the crankshaft and the position of the fuel injector drive wheel relative to the crankshaft, seems correct, the injection start might still be far outside the tolerance range. So, I would first check the crankshaft position sensor. If that's okay, then loosen the pump and try to adjust the injection start within the tolerance range. According to VAG's installation instructions, after replacing the fuel pump, it should be set to approximately the middle of the adjustment range defined by the pump bracket. This should at least allow the engine to start, and then you can proceed with dynamic (fine) adjustment. We once had a case where a 'professional' workshop, during a timing belt replacement, probably twisted the crankshaft by one tooth while installing the timing belt onto the camshaft wheel. They then adjusted the fuel injector in such a way that the engine started and ran somewhat normally. However, it lacked power and didn't run smoothly. When we corrected the timing, the engine wouldn't even start anymore... And I suspect something similar might be happening to you, assuming everything else is truly correct.