ESP Failure: Troubleshooting & Solutions

Hello everyone,

Today, I feel I need to speak up.
I'm having a problem with my Audi 80 B4 TDI, manufactured in 1994, engine code 1Z, with approximately 220,000 kilometers on the odometer.
"For some time now, it's been running very unevenly at idle. Sometimes it sounds like it's only running on 3 cylinders. It also has a slight hesitation in the lower RPM range."
I just took the car to the workshop, and they told me it's a "sawing" idle. However, the workshop doesn't have the equipment to properly diagnose the issue. So, my mechanic took the car to Audi. There, they found that the fuel pump has a significant fluctuation in fuel injection volume during idle, ranging from 16mg to 25mg (don't hold me to those exact numbers).
Now, at my request, the valve timing and the fuel injection pump have been adjusted. I had hoped that the problem originated from my timing belt replacement, but that was four years ago.
Of course, that was nice of you. I probably should have expected it.
Nunja Ergebnis laut Werkstatt: Pumpe im Eimer. Kosta: 1150 Euronen incl. Installation.
Well, I should actually be happy, because when I look at the other posts, it seems like the price I'm paying for this is still relatively cheap. But somehow, I can't quite bring myself to feel happy about it.

Unfortunately, I can't read the ECU myself because my adapter isn't working properly yet. (Yes, it's my lucky week.)

Well, does this sound familiar to any of you?
Does anyone have a suggestion?
Will I be able to get around to replacing the pump?
Is there anyone from the Bad Kreuznach area who might be interested in joining me for a test drive sometime? I'm still a bit hesitant about it.

Was mir noch einfällt: Die Möhre hat noch andere Fehler drin. VMax nur 160, bei 120 ab und an Leistungsstop. Macht er mittlerweile glaube ich auch schon im 4. Gabbreviations
Error entry in the engine control unit (ECU): Intake manifold pressure control differential, intake manifold pressure sensor - short to positive.
It actually doesn't have anything to do with the idle speed, right???

See you then.
Markus.

zocker100 wrote:

Ergebnis laut Werkstatt: Pumpe im Eimer. Kosta: 1150 Euronen incl. Installation. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. Well, does that sound familiar to any of you??

Hi,

I know of a case involving a Honda Accord TD with engine code VP 37 that exhibited very similar issues.
Since the new pump was installed, everything is working fine again: no more jerking, full power (before, the top speed was about 30 km/h lower), and the engine no longer stalls (!!).

Hi Ulf,

Based on what I've seen in other posts, the behavior suggests a faulty flow meter. Am I interpreting this correctly?

When I asked the workshop what exactly was wrong with the pump, I only received the response that they couldn't determine the issue. That can't be right.

I'm thinking that since I need a new pump anyway, I might as well take the opportunity to examine the part more closely.

See you then.
Markus.

zocker100 wrote:

Based on what I've seen in other posts, the behavior suggests a faulty metering valve. Am I understanding this correctly??

Hi,

"Yes, with some reservations (e.g., VAGCOM measurements)."

Quote:

When I inquired at the workshop about what exactly was wrong with the pump, I only received the statement that they couldn't determine it in that way.

That can't be right.
It's quite possible, because a VP37 is a small masterpiece, and only true experts can precisely identify what's not quite right.

As a Holzhammer test, you could try removing the pump cover and checking if the measurement short-circuit ring moves freely (against a return spring) and if the shaft has any noticeable axial play (refer to the image in the technical article about the function of the MSW/RWG).

If the test results are different, then the MSW is certainly damaged to some extent, or possibly blocked by foreign objects.

Hi Ulf,

First of all, thank you for your help.
Currently, the software recognizes my interface. I will test it tomorrow on my control unit. I hope I get lucky. (Although, it's actually my lucky week ).
Then, by reading the error codes, it should be possible to identify where the problem lies. (I hope you can help me with this.)

I'm still waiting to unscrew the lid. I can already tell that it's not going to be easy to get off.

I actually thought the workshop would be able to pinpoint the exact problem through measurements.

See you tomorrow.
Markus.

zocker100 wrote:

I'm still waiting to unscrew the lid. I can already imagine that it won't be that easy to get it off.

Hi Markus,

Please enter "triangular screw" in the search function. You will find a topic I created about manufacturing a nut for that type of screw for the ESP. Is the car having starting problems?

Hello.

The VP37 is easiest to remove if you have a small hand drill with a diamond cutting disc (like a Dremel or Kress, or something similar).

Then simply grind a slot into the head of the triangular screw and use a regular screwdriver to tighten it. (ULF: Would this be suitable for tips and tricks?)

Then, perform Ulf's suggestion: check the quantity setting mechanism for ease of operation.

Before I would replace the pump, I would first try to find out if there might be a problem with an injector or the fuel pressure regulator. Replacing the ESP (Electronic Stability Program) is already a lot of work, although admittedly, the suspicion of a problem with the ESP is quite high.

If the signal box is jammed, that's the problem. Then try to remove the signal box from the vehicle. You can't break anything else at that point. If you can't get it back together, the ESP (Electronic Stability Program) will have to be removed anyway.

If you manage to remove the control panel, you'll have the opportunity to install a different one without having to completely remove the entire Electronic Stability Program (ESP) system.

You can often find pumps (with control systems) for sale on eBay.

Good luck, let me know how it turns out.

Have you ever used biodiesel or rapeseed oil as fuel?

Hello everyone,

Great participation!

Yay!! My interface is working with my car. I read the error codes. It also works when the engine is running. I've also looked at some parameter blocks.

Ulf, what data would be interesting to you right now? What should I pay attention to when collecting the data?

@haehnlein: Yes, I've already seen the instructions. But I want to wait a bit before opening it up. It doesn't have any starting problems; it starts up within about 1/2 second. And then it runs, but not smoothly.

@garth.brooks: That's exactly what I mean. I can't afford to lose much more. That's why I'm considering cleaning the quantity setting mechanism. (Am I taking on too much?) I would just like to know if that's also the reason. Have you ever had that mechanism out before?
Biodiesel was already in the carrot. What do you mean by "PÖL"?

I just measured the resistance at the pump connector (the black, 3-pin connector attached to the pump).
Upper pin to middle pin: no connection.
Middle pin to lower pin: 15 Ohms.

If I remember correctly, the resistance should be the same between all the pins, or should it?
The upper pin extends upwards from the pump to a round part.
The middle and bottom sections go down towards the pump.

To the side of the pump, there is a black plastic cover into which another cable bundle enters. It also has a triangular screw. Is the flow control mechanism located underneath it?

See you then.
Markus.

Hello Markus,
Behind the black cover is the control slide valve of the quantity setting device.


Best regards, Rudi.

Rudi wrote:

Right behind the black cover is the quantity setting mechanism. Best regards, Rudi

Hi Rudi,

You have to remove the entire top part of the pump to access the MSW, not just the black cover (unfortunately, I haven't reached that stage yet ). Also, it's not possible to drill a slot into the triangular screw due to its recessed position. How much diesel will come out when removing it? Although the gasket held somewhat during my partial removal attempt, a certain amount of diesel could leak out when removing the entire top part .

garth.brooks wrote:

Then simply grind a slot into the head of the triangular screw and use a regular screwdriver to screw it in. (ULF: Would this be suitable for tips and tricks?)

Hi Garth,

I have updated the MSW/RWG technical article accordingly (including the tactile test).

zocker100 wrote:

Ulf, what data would be interesting for you right now?

Hi Markus,

Unfortunately, I don't have any experience with specific measurements that would definitively indicate a faulty pump.

A significant "jumping" idle speed or fluctuating idle volume (variations of over 1 mg, usually in conjunction with corresponding speed fluctuations) without changes in engine load could, in my opinion, indicate a "worn out" pump.

Hi,
@ Haehnlein:
Okay, caught you. Since the discussion before was essentially about the rule-changing, gear-shifting lid, I didn't formulate it more precisely .

Sure, here's the translation:

'It has been corrected.'

Die Dreieckschraube ist offensichtlich nicht bei allen Deckeln gleich. At my...
The pump is protruding enough that I can use the three-jaw chuck of a cordless drill to unscrew it.

Best regards, Rudi.

ulf wrote:

Unfortunately, I don't have any experience with specific measurements that would definitively indicate a faulty pump.

Hi,

That's not exactly what I wanted to hear. But I'll still record the values and post them. Maybe we'll see something.
Unfortunately, I can't do that right now because I first need to find a laptop with a COM port.

What I've observed so far is a fluctuating idle fuel consumption, ranging from 2.4mg to 6.4mg. This also affects the idle speed, which varies from 819 to 880 RPM.

See you then.
Markus.

zocker100 wrote:

What I have already observed is a fluctuating idle fuel quantity, ranging from 2.4mg to 6.4mg. Consequently, the idle speed also fluctuates, from 819 to 880 RPM.

Hi Markus,

if these fluctuations occur within a VAGCOM measurement only }at idle, without changing the engine load (steering, climate control, or electrical consumers on/off), then it is quite certain that there is something wrong with the pump, because such variations are, in my opinion, extremely high (I consider about 0.5 mg to be normal, within 1 minute or longer).

I hope that the engine control unit wasn't modified for tuning attempts (-> see the article on DIY solutions for engine knocking), because that could potentially cause similar symptoms in extreme cases. However, the average mg values seem too high for that to be the likely cause.

If you don't hear from me for a while: we're going on vacation. Bye!

Hi,

Our pump specialist is going on vacation *sob*.

@Markus:

Take a look at Ulf's article (diy-ruckelabhilfe) and experiment with it: it's not really that difficult. If you can access the ESP screw, it's not a problem. However, mark the position of the pump's upper part using a scratch line or similar. It's best to do this in two or three places. This isn't millimeter work, but rather tenths-of-a-millimeter work. You'll need a few attempts. I have mine set to approximately 6 mg/stroke. Be careful: the pump is leaner when the idle value is higher (yes, the programmers), and the higher this value, the leaner the throttle response .

With VAG-Com, you can also adjust the fuel quantity within certain limits under the "Adaptation" section. First, you need to enter "12233" for login... (Unfortunately, I don't have access to my laptop right now, so I don't have the program in front of me at the moment - using the search function).