Seat Ibiza Starting Problems (AHU)

Here's the translation:

'It's about a Seat Ibiza TDI, manufactured in 1997, with engine code AHU, and approximately 150,000 kilometers on the odometer.'

A few weeks ago, I had a major service (regular maintenance) done at a Seat-certified garage. About half a week after the service, the problems started. I'm experiencing starting problems (engine cranks for 10 seconds), and the engine jerks when it returns to idle after being under load (this is also intermittent).

So, I took the car back to the garage, and yesterday, after almost a week and still with the same problem, I picked it up again.

'By 'warm start,' I mean a truly warm engine, not just 5 seconds off and then on again -> it cranks and then immediately starts with a loud noise for about 10 seconds! The starter motor spins quickly, both when the engine is cold and warm, at around 200 rpm.'

'Something I noticed yesterday is that if I turn the ignition key, then before the engine starts, I turn the key back to the 'off' position, and then immediately turn it all the way to the 'start' position, it will start.'
While idling, there's a cloud-like emission (presumably fuel?) coming from the exhaust.

Rolling uphill, he executes the first attempt perfectly, without any noticeable delay.
The following components have already been checked: injectors, diesel filter, compression, R109 (presumably a specific part or system), fuel shut-off valve, engine sensors, fuel delivery rate, fuel injection timing -> all okay (according to the workshop).
'Feeding the ESP directly with diesel in the engine compartment caused the same problem. The mass airflow sensor (MAF) is acting like a diode, and the EGR valve has been 'broken' for a while.'

'Once it starts running, it runs smoothly throughout the entire RPM range with the usual power, without any hesitation. The only time you might feel a slight hesitation is when you completely release the accelerator (thrust mode) and the RPM drops below idle. At that moment, when the fuel injection restarts, you might sometimes feel a slight jerk.'

The master technician in the workshop was quite desperate himself and wasn't really sure what to do. He suggested replacing the VP37, but considering the price of that part...

At first, I thought it might be the battery, but as described, the starter motor spins quickly and smoothly, and that wouldn't explain the issue with the shifting between reverse and drive.

Does anyone have any idea what this might be?

Also beim Warmstartproblem tippe ich ganz eindeutig auf eine zu schwache Batterie. Mach doch mal den Test mit vernünftigen Starthilfekabeln von einem 2. Get out of the car.
If it starts right away, then it's 99.9% likely that the battery is the problem.
A noticeable jolt when pressing the accelerator at low RPM is normal because the engine speed control system intervenes strongly in that area to prevent the engine from stalling.

I bet your problems will be a thing of the past with a new battery!

Regards,
Alex.

Today, I tested it, but there was no success . It was roughly the same, maybe a few seconds shorter.
I also tried adjusting the initial fuel quantity via the MSG setting, but that didn't change anything either. What I noticed during all this troubleshooting is that quite a bit of diesel fuel ended up on the floor at the back, so it seems like enough fuel is already being injected. Also, the injection quantity at idle (903 RPM) is 5.0mg/stroke, which should be okay for these temperatures, right?

'I also noticed something: there's obviously a little bit of diesel leaking out of the overflow nut on the ESD of cylinder 2 (at the top, where it connects), and I can also see some diesel further down, near the injectors and the engine block. Is there a suspicion of a leak in that area?'

I also checked the connectors on the pump and the ones on the control module (MSG). Everything seems clean and dry.

It's possible that it's drawing air in when the engine is off.

Hi.

Quote:

What I've noticed during all this tinkering is that quite a bit of diesel oil has ended up on the floor, so it seems that enough is already being injected.

Please keep an eye on the injection timing (valve timing) in the default setting mode.

Best regards, Rainer.

I'll probably take a look at it tomorrow, even though the workshop assured me that it's okay. I assume it's running at its operating temperature, right?

I came across the following in a post by heri while using the search function today.


It's not uncommon, but it can happen that the two valves in the high-pressure section break. This has the effect that the injector lifter is no longer pushed back to its starting position. As a result, no or very little diesel fuel is pumped. However, if the engine is already running, it seems to be enough to push the lifter back. Eventually, it won't start at all, or only with a push. The damage can be repaired for approximately 300 euros, including adjustment and sealing. However, this is only possible with a skilled Bosch service center; other places will try to sell you a replacement pump.

Symptoms: Difficulty starting, requiring several seconds of cranking. Same issue when warm or cold. Smoke emitted during and especially after starting. Slightly increased fuel consumption or a slight decrease in performance. An error code may or may not be present, but if there is, it might be related to something like a quantity regulator, etc.


There was no record of any errors, but the starting behavior and the issue with the cubs match.

Okay, I connected the diagnostic adapter again today to collect some data.

I have uploaded the logs (HTML, XLS) and a Screenshot from TDIgraphhttp://tuxedo.ath.cx/ibiza/startproblem/.

The log file shows idle operation with a few instances of acceleration, and the TDIgraph is also showing idle.

'When comparing with data from March 2004, I noticed that the 'Actual Start of Inj' value is currently at 2° at idle (warm engine), whereas in the older records, the value was around 0.5-0.7° (also with a warm engine).'

As soon as the laptop has power again, I can post data from today's shift at MSW Block 004.

Okay, here's the promised log for MWB004.
http://tuxedo.ath.cx/ibiza/startproblem/2006_02_07-18_34.html
At the beginning of the log, the engine is running at idle temperature.
Okay, engine off, and let's try starting it. It's great to see that the RPM is around 300, which is a pretty good range. Then, engine off again, and right back on, repeating the process. The only thing I don't like is the angle (the difference between the target and actual values).
Did the workshop cut corners on that?

I picked up the car from workshop No. 2 today, and the nice mechanic:
- Mechanical check of injection start -> OK.
- Compression re-checked -> +/- 27 bar.
- The fuel lines from the ESP were disconnected -> Diesel fuel is reaching the injectors during the starting process.

So, to put it briefly, I'm now at roughly the same point as Aesop in this thread.

Or does anyone have any other ideas? It's quite a strange symptom that I noticed during testing today.
1. Start the engine with a jump start.
2. Turn the engine on with the key, but immediately turn the key back to the 'on' position.
3. Wait for a period of time t (tested range: 3-20 seconds).
4. Turn the ignition key to the 'start' position.
5. The motor starts after about one second.

Could that be the ESP? The car is quite old, and a VP37 isn't exactly cheap... } So, I want to be 'sure' <- sure is only death, I know } that it's the ESP, and in this case, the likely cause is excessive leakage from the pump piston, which is probably broken.

In this context, the next question arises: why specifically shortly after the service? Could a 'dry run' have 'triggered' this defect (after the diesel filter was changed)?

Perhaps there is no connection, but in my opinion, an ESP should...
It should be able to last a bit more than 150,000 km.

Could a change in the ZR (presumably a component or setting) potentially cause a rotation of the NW (likely a measurement or angle) by +/- 2-3 degrees?

then --> cold immediately

warm --> organ

It was also checked by a mechanic I trust, and it was/is okay.

The problem is still ongoing. I'm still in the process of discussing the warranty for the maintenance work with the workshop. It might take some time, and I'll let you know when there's any news.

Organ greetings from Switzerland

Hello everyone,

Today was the big day; the pump that I was able to get from mullemaus was finally installed by the SEAT workshop.

But... The car starts immediately and nicely, as always, but the LL-DZ (low load - diesel zone) fluctuates significantly. It's audible and visible (the engine constantly surges forward and backward). Under load (manual air conditioning on), I feel it's almost even worse. As soon as I give it a little gas, the DZ can be kept constant with the accelerator pedal (provided I have a light foot).
Even when driving at low speeds, and then slightly adjusting the accelerator, it causes quite disturbing jerking! Could it be the N75 valve? If so, why is it suddenly happening now, seemingly out of the blue?
'Another thing I've noticed is this clicking sound – click-click-click, etc. – which, as far as I know, comes from the N75 valve. It's not audible in the low-load (LL) mode, but it *was* definitely clicking in the LL mode before the fuel pump modification (yesterday). Now, it's not clicking in the LL mode.'

Or does that have something to do with...?
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.
What should I do? Based on the symptoms, yes, but I think the pump should actually be okay now.

I'm honestly at a loss. Is the workshop incompetent? Before I start posting a lot of complaints, I wanted to ask if anyone here has any ideas.

Thank you very much!

So, it's not the pump. It has been test-run on a test bench. I don't know if adapting it will make a difference. Who installed the pump? Is the timing belt installed correctly? These large fluctuations could also be caused by differences in compression between the individual cylinders. Are the injectors okay? Have you read the measurement block 13 times?

The pump was installed by a SEAT authorized service center (although that doesn't necessarily mean anything).
I'll definitely go back there again tomorrow to check on that, it's such a hassle dealing with those guys! Hopefully, the timing belt is also installed correctly. As I said, I actually took my car to a workshop so I wouldn't have to worry about *everything* *sigh*.

The compression is approximately the same across all cylinders and was checked during troubleshooting of the starting problem.

Are there any other areas I could investigate? I'll definitely ask the workshop supervisor if he can adjust channel 1 to see if that makes a difference. But if you say the ESP was on a test bench, then it should be okay, right? Am I wrong about that?

It was also briefly on the highway before, and it seems like the performance is sufficient. It accelerates nicely up to 180 km/h, just like in the good old days. The engine runs smoothly if you give it enough gas. However, when you're using little gas, especially in lower gears, you can feel/notice that the whole car jerks forward and backward until you either completely release the gas or give it more, then it settles down again.

What I now know is why my old VP37 wasn't working properly. I think that once the springs are back in good condition, it should work again.
http://tuxedo.ath.cx/ibiza/vp37/IMG_9667.jpeg
http://tuxedo.ath.cx/ibiza/vp37/IMG_9668.jpeg

I received a phone call from the workshop today; they tried their best to get the car running properly, but no chance! The engine still vibrates like crazy in the partial load range . He also showed me the data for the injection timing on the VAG diagnostic tool, and it's absolutely within the normal range!

The only thing that brought a slight improvement to the LL (likely referring to a specific system or process) was that the administrator had temporarily reduced channel 1 in the MSG (likely another system or component) to its minimum possible value.

Furthermore, the unerasable (-> recurring) error occurs.
01268 - Quantity Adjuster (N146)
18-10 - Upper Limit - Intermittent
Okay, I'm assuming that N146 is likely the MSW.

Why is that? The pump is model 028 130 115MX, which is the replacement for my 028 130 110H, so it should fit. It's from 'mullemaus' and should be okay.
It's clear from the pictures above that the old fuel pump was faulty. Since the tractor ran perfectly fine before, despite having been taken apart previously, I don't think anything else is broken or will break.

I just wobbled my way home with the unstable contraption, always keeping the accelerator pedal in the right position (which actually makes it work okay!), and I switched on the data logger.

Engine idling with two throttle blips.
http://tuxedo.ath.cx/ibiza/vp37/daten01.html
I find the injection amount for LL to be quite high at 7-9mg/day, don't you?

Engine idling, speed control.
http://tuxedo.ath.cx/ibiza/vp37/daten02.html
It's noticeable that the idle speed control is quite erratic, even though the engine now runs relatively smoothly (higher idle speed, not logged here, but almost the same values as low load).

Okay, so the big question is, what's the dumbest thing I can do now? I could get a replacement fuel pump from Bosch for around 20 CHF, and then try to fix the old one (would I need to put it on a test bench after replacing the spring?). But then the workshop would have to do a re-installation, which I can't do myself, nor do I have the space to do it.

Okay, so, last Friday, the saga of my Ibiza, AHU, finally came to an end! The second replacement fuel pump (directly from BOSCH) was installed on Friday morning, and I was able to pick up my car on Friday afternoon .
What can you say, it runs like new. Acceleration, engine start, partial load... heavenly . I'm still checking with mullemaus, apparently the error demon struck, and this good thing (the first replacement pump) had a problem somewhere along the way (damn post), the packaging was top-notch, but if they're practicing for the World Cup with kicking instead of delivering, that won't help either .

The dark cloud hanging over everything is the price of history; ~1900 CHF is quite a sum. But my patience was really stretched thin, as I simply need the car every single day.

Perhaps as an addition, I had initially considered restoring the old pump by replacing the springs. However, after a closer examination of the broken spring pieces, I realized that some small fragments are missing, and I have no idea where they might be inside the pump. Since I often drive further than just to the supermarket around the corner, and I would find it quite troublesome to be stranded somewhere with a broken pump, I have reluctantly decided to go with a 'new' pump.

Perhaps as a general question: How often does this happen with the injectors breaking? The technical article 'Instructions for repairing a VP37 distributor head' also reports such a problem, and I've also seen similar cases discussed in the forum. Is there any known cause for this, or is it really just material fatigue (which would be a bit 'shocking' at only 160,000 km)?