Pump Seal Failures: Troubleshooting & Solutions

Hello fellow diesel enthusiasts,

I had to replace the seals on the mass airflow sensor housing. This was the first time I've done it, and I also replaced the upper and lower seals at the same time.
Okay, I'm having a problem: the engine (1Z, manufactured in 1993, in an Audi 80 1.9 TDI) won't start. I've already completely disconnected the battery. What could be the cause? 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 pin, so that you could accurately align the installation position again?
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 timing unit 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 movement is a maximum of 3-4 mm.
The initial start-up attempt showed that the engine was attempting to ignite, but was unable to 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 running and responded as it did before the repair.
Perhaps someone else has the same problem and can find this post helpful.
Regards,
Hans.

Hello Hans,

We've already discussed this topic. I recommend adjusting the setting 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.

Deleted upon request.

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, the correct position of the turnout is determined 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 re-establish the correct association between the position of the quantity setting device and the HDK signal.

It would be a major coincidence if everything worked as before with the "Hammer" method, and I also consider it highly unlikely.

@diesel.gustav:
Under https://community.dieselschrauber.org/en/viewtopic.php?t=3128, there are lists of the target values for the different engine codes. In measurement block 2, value 1, you only need to read the value for "1Z" to see what is considered "normal".

Best regards, Rainer.

Deleted upon request.

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 tail. If this were a seasoned, professional circus performer, I'd say, "well, that's the way it is," because "the show must go on!" and he knows exactly what he's doing. And he also knows when he's going to fall on his face. 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 have the pump removed and 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 that 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, without taking any further precautions. The ESP (presumably a wine cooler or similar device) is now reinstalled and 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 previously taken measurements 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 even demonstrate the correct settings for you in person.

Best regards, Rainer.

Therefore, I suggested in https://community.dieselschrauber.org/en/viewtopic.php?t=4327 that we measure the HDK voltage at idle. This way, we can also get some real reference values for all the machines...

CU Gremlin.

Deleted upon request.

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...

'@ Gustav, I agree, it's VERY difficult to readjust a misaligned flow meter. I only managed to do 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. I once compared my pump to another one, and the difference was 0.8mm. So, simply measuring one and transferring the measurement to another isn't accurate either.

I would like to contradict the statement in this forum post. It IS possible to adjust the ESP (Electronic Stability Program), but I had to open mine 20-30 times before it was properly calibrated.

'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. All 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 life.'

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!

Sure, so you can see that the upper part of the pump can be disassembled, placed on the desk, and then reassembled, allowing the pump without a pump test stand or other high-tech equipment that isn't readily available to 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 others, seems to be quite justified.

Quote:

Your assumption, as far as I am concerned, that drinking four glasses of red wine and then having a pump overhaul and adjustment is concerned, is far beyond the realm of reality and exists only in your imagination. It would be - just like driving a car with alcohol - irresponsible to the point of being criminal.

Hmm, what exactly do you mean by that? It sounds quite grumpy to me. I can't quite figure you out.
Try to incorporate coziness, tranquility, and comfort.

Best regards, Rainer.

Hello,

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

Others 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" or similar damage -> therefore, it is definitely not recommended for imitation .

@Gustav:
I'd be interested to know what can potentially go wrong during the adjustment of the fuel mixture using the indicated idle quantity (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 actuator (i.e., parallel to the pump shaft), and with a little practice (and luck), it is possible to match the previous reading with an accuracy of 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 upon request.

Hello.

diesel.gustav wrote:

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

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

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' involved.

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

From my perspective, Hans Baldauf's problem seems to be 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.

Update: Exactly what you're complaining about is happening right now at "Grauen." Ironically, it's about the same topic. I won't be adding any further comments on this.