Starting problems after pump seal replacement

Hello fellow diesel enthusiasts,

I had to replace the seals on the mass airflow sensor housing. This was the first time I've done this, and I also replaced the top and bottom parts at the same time.
Okay, I'm now facing the problem that the engine (1Z, manufactured in 1993, in an Audi 80 1.9 TDI) won't start. I've already completely removed the battery. What could be the reason? I absolutely need the car tomorrow afternoon.
If you have any advice, you can reach me at 037343/2642.
Thank you for any advice.
Best regards, Hans.

Hello Hans!

Did you make any kind of mark between the lid and the housing, for example with a needle, so that you could accurately align it when reinstalling?
If it's lost, it could be really difficult to find the correct setting again, because even a slight shift of just a few tenths of a millimeter can cause the engine not to start at all (too lean setting) or to immediately over-rev shortly after starting (too rich setting).
Please exercise extreme caution when trying to find the setting again.

Regards,
Alex.

Hello "donalexo",
First of all, thank you for your tip.
I moved the fuel injection pump housing (MSWG) to the front position (towards the timing belt) and only tightened two screws by hand, just enough so that the entire housing can be moved with slight force, without any diesel fuel leaking out.
Using a small hammer and a piece of hardwood, I then shifted the housing about 1 mm towards the connectors for the fuel injection lines. The total possible displacement is a maximum of 3-4 mm.
The initial start attempt showed that the engine was trying to ignite, but it couldn't continue running on its own power.
After approximately 2.5 mm of movement, the engine started, but when the accelerator was pressed, there was a noticeable uneven transition to the idle speed, and the engine ran unevenly at idle.
I gave the casing a slight nudge in the specified direction, and sure enough, the motor started and responded as it had before the repair.
Perhaps someone else has the same problem and can be helped by this post.
Regards,
Hans.

Hello Hans,

We've already discussed that topic. I recommend adjusting the cap so that you have an injection amount of approximately 4-5 mg per stroke when the engine is warm and no consumers are turned on.

Best regards, Rainer.

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Hello Hans,

Quote:

Did you take into account when making your recommendation that the actual injection mass in mg/working cycle and cylinder cannot be measured, but can only be approximately calculated from the signal of the engine control unit (ECU)?

Sure, that's the trick: based on the signal from the HDK (presumably a device), the correct position of the turnout is determined and set retrospectively!
The idle speed of a warm engine without any accessories running is approximately a fixed value, as long as the engine is not damaged or if there is honey in the oil pan.
By adjusting the position of the quantity setting device so that the 'expected' value for the injection quantity can be read, it is possible to restore the correct association between the position of the quantity setting device and the HDK signal.

That everything would go back to normal with the "hammer method" would be a major coincidence, and I also consider it highly unlikely.

@diesel.gustav:
You can find lists of target values for the different engine codes at the following link: /viewtopic.php?t=3128. In measurement block 2, value 1, you only need to read the value for "normal" for the 1Z setting.

Best regards, Rainer.

Deleted as requested.

diesel.gustav wrote:

Hello Rainer, I'm sorry, but this "approach" is causing me some amusement. It's kind of like a rider mounting their horse from the rear. If this were a seasoned, professional circus performer, I'd say, "well, that's just how it is," because "the show must go on!" and he knows exactly what he's doing. And also, when he falls on his snout. You have very few professionals like that in your circus. ...

He has already fallen on his face (or the child has fallen into the well) .

What do you suggest now, should he remove the pump and have it replaced?
What do you think he will do if he has the choice between paying 1000 euros for repairs at a workshop and driving to a friend's place who has a diagnostic tool?

My question to you: Let's say you spontaneously switched to a different type of wine, specifically a red wine, because you had a bit too much on hand, without making any other arrangements. Now, the ESP (Electronic Stability Program) has been reinstalled and is working properly. How would you proceed the next day, after the headache has subsided?

Apart from that, the basic settings can be reproduced quite accurately using the method described above (provided that you have measured beforehand and the conditions have not changed). If you don't believe me, try it yourself. If my Christmas wish happens to be under the Christmas tree, I could then demonstrate to you, in real-time, a meaningful new application for it.

Best regards, Rainer.

'That's why I suggested in /viewtopic.php?t=4327 that we measure the HDK voltage at idle. Then we can finally get some accurate readings for all the machines...'

CU Gremlin.

Deleted as requested.

hello

I somehow thought this was a discussion forum, and it shouldn't be used as a platform for people to attack each other, especially not those who possess knowledge!


@ Rainer, I can imagine that we might reach a point where the system starts working again, and then we can begin fine-tuning it, but...

'Hey Gustav, I agree, it's VERY difficult to readjust a misaligned flow meter. I only managed it after I built a measuring setup with a micrometer screw that provided reproducible values, and I knew, within about 2 mm, where I needed to be. It wasn't possible with a caliper because I couldn't apply it reproducibly. The adjustment range I determined between the upper and lower error limits was 0.5 mm.' And mine wasn't disassembled beforehand.

The exact location of the point depends heavily on the reference plate used. I once compared my pump to a different one, and the difference was 0.8mm. Simply measuring one and transferring that information to another isn't possible either.

I would like to contradict the statement in this forum post. It IS possible to tune the ESP (electric sound post), but I had to adjust mine two or three dozen times before it was properly tuned.

'Red wine, even with alcohol, slows down your reaction, but it can also make you more relaxed – and can actually be helpful for very delicate work. I can now completely disassemble a Canon ixus, fix the E18 lens defect, and reassemble it. I can do it in 2 hours with half a bottle of red wine. And if something goes wrong, something is broken that was already broken beforehand.' That's live.

Hello,

Quote:

I'm quite familiar with how to set up a pump, so there's no wish list under the Christmas tree.

It would also be bad if that weren't the case.

Quote:

But thank you for offering to show it to me!

Okay, so that you can see that the upper part of the pump can be disassembled, it can be rolled around on the desk, and then reassembled, and the pump without a pump test stand or any other high-tech equipment that isn't readily available, can be properly adjusted again.

Unfortunately, you haven't answered my question about what you would do with Hans Baldauf's pump in its current condition.

Here's the translation:

"I have another question for you: how precisely must the original base position of the track switch be set?"
My answer would be: so precise that the engine control unit can no longer detect any difference. What is your answer?

The image of the "sacred cow" fuel injection pump, which has already been presented by other people, seems to be quite justified.

Quote:

Your assumption, as far as I am concerned, that I would use cheap red wine and then have a pump overhaul and adjustment, is far beyond the realm of reality and exists only in the realm of your imagination. It would be - just like driving under the influence of alcohol - irresponsible to the point of being criminal.

Hmm, what exactly does that mean? Reading that makes me sound quite grumpy... I can't really figure you out.
Try to incorporate comfort, peace, and coziness.

Best regards, Rainer.

Hello,

Regarding Hans' adjustment of the pump using the knocking method without any further measurements, I believe he was incredibly lucky to have found a position where the engine behaves (approximately / largely?) as it did before.

Someone else might have revved the engine up so quickly when starting it that they might just be able to turn off the ignition before there's a "piston-valve salad" situation, etc. -> therefore, it is definitely not recommended to imitate this .

@Gustav:
I'd be interested to know what can potentially go wrong during the adjustment of the throttle linkage using the indicated idle speed (assuming the engine is always running under the same conditions: coolant temperature, load, weather, etc.).
The displayed amount reacts very sensitively to longitudinal shifts of the metering unit (i.e., parallel to the pump shaft), and with a little practice (and luck), it's possible to match the previous reading with an accuracy better than 1 mg per stroke.

What tolerance is typically used in a pump test stand when only the valve position needs to be adjusted?
Is it possible that the lateral and angular position of the valve body on the pump housing is being fine-tuned?

Deleted as requested.

Hello.

diesel.gustav wrote:

...In this sense, I am ending the discussion for myself. Whether you become enlightened by me or not? I don't know!...

No, it's unsatisfactory. Because you have only partially answered my questions, even though you yourself place great importance on it.

Since Hans Baldauf changed the poetry himself, before he asked about it in this forum, I also don't see any 'animation' or 'reckless behavior without regard for losses'.

This is about damage mitigation, specifically to avoid the need to install a replacement pump.
Your arguments, therefore, seem unfounded to me.

From my perspective, Hans Baldauf's issue is resolved. He now has the option of trying a fine-tuning adjustment using a diagnostic system, or having a replacement pump installed.

Best regards, Rainer.

P.S.: In "Grauen," exactly what you're complaining about is happening right now. Ironically, it's on the same topic. I will not provide any further comments on this.