Audi Starting Problems? ESP Failure Diagnosis.

Hello,

I need your help again; I'm stuck.

A friend came to me last Saturday because his Audi A4 with a 66kW AHH engine, manufactured in 2000, was taking a very long time to start. I initially suspected a leak in the diesel fuel line, but that hasn't been confirmed today.

The problem is as follows: The car was running without any issues, without any hesitation or loss of power, until suddenly, after driving approximately 70km and being stationary for 1-2 hours, it required a very long cranking time to start. Last week, I checked the fuel injection timing, which was fine, and then I discovered defective glow plugs during a general inspection (I wasn't sure they were the problem, as it also had difficulty starting when warm). I replaced them with new ones. The engine started after about 30 seconds of cranking and, compared to before, ran more smoothly in the cold state and immediately on all cylinders. After about 2 minutes, it turned off on its own and hasn't started since.

Today, I disconnected the supply and return lines directly from the ESP and connected the supply line externally so that it is supplied with diesel, and the return line is connected to a container. The pump was bled. However, it still won't start. In the diagnostic module 1, field 1 shows approximately 220 rpm when turning, field 2 shows an amount of 38 mg/H, and field 3 shows a voltage of 7,... V, which is within the normal range. However, in diagnostic module 19, the voltage in fields 1 and 2 is permanently at 0.000 volts.
Could it be a defect in the pump or the flow meter?

P.S. After the problem started, the engine would only start poorly after being left idle. That is, it would start after a long cranking period, but if you turned it off and immediately restarted it, it would start immediately. And after the problem first appeared, only about 120 km were driven, and the engine was started maybe 10 times.

If anyone has any ideas about the cause of the error, please report it. Any help is appreciated.

What temperature does it display when it's cold? It sounds like it might be the coolant sensor.

"Why temperature sensors? Could that be the cause? I suspect a faulty ESP (Electronic Stability Program) is the reason. The error code G62 is stored as intermittent. In diagnostic block 7, all three fields are close to each other when the engine is cold."

It reminds me a bit of the problem I had when I started.

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It was just as difficult to start my car after parking it as it was after a long period of inactivity.
"In my case, the engine started on its own (without the use of starting spray)."
It sounded like it was struggling to get going from low RPMs. It had less power at lower engine speeds.

It's also possible that the return springs for the booster pistons have broken.
It has happened before.

I would say try removing the screw at the front of the HD part. That's probably the easiest way.
The rest gets more complicated.

Hello,

"Daily soup" - Which screw are you referring to exactly? The one at the back of the ESP, between the connector supports for the injectors?

I've now removed and disassembled the high-pressure pump. The two high-pressure springs are not broken. Otherwise, I didn't see anything unusual from the inside. However, I noticed something: when you turn the pump at the drive, you can hear a strange scratching sound between the four pressure build-up points.

Have the ESP checked by the Bosch service on February 1st. However, I am open to suggestions for troubleshooting in the meantime.

Wishing everyone in this forum a HAPPY NEW YEAR.

Yes, that's the one I mean. The large, triangular one.

The scratching sound could be caused by a leak at this screw, where air is being forced through.

Bosch service? I think you'll get better and cheaper results if you try to find the problem yourself first, or if you buy a used pump.

The mechanic at Bosch seems very competent, gave some helpful advice, and most importantly, he didn't talk nonsense like the guy at the dealership.

The inspection of the VP37 is expected to cost approximately 30-40 euros.

30-40 eggs?

For that, you will receive a maximum of one external visual inspection .
Or maybe you have a good relationship with the Boschmann.
Accurate pump tests with a pressure curve cost 200 euros or more.

I had the ESP (Electrical Submersible Pump) checked today, and the result was that the pump is working correctly. The inspection, including a new seal kit and adjustment, cost 240 euros.
And the worst part is that the error persists, and the engine still won't start.

Does anyone know of any other possible causes?

What also caught my attention is that in the MWB 13, during the organ's operation, the displayed injection quantity for all nozzles is 0.0 mg/H. Is this normal? Does it only display the injection quantity when the organ is running?

Does the VAG diagnostic tool display the engine speed correctly during organ-pipe sounds? Very rarely, the crankshaft position sensor can fail. I once had a similar problem in a modified street car with an industrial TDI engine.