A6 2,5 TDI springt nicht mehr an | Posts 16+

I can't say for sure yet, as a friend is getting it for me. However, the cost will depend on the extent of the repairs needed for the faulty ESP (Electronic Stability Program).

Hello.

Unfortunately, I have to contact you again.
This weekend, I received a call from the owner of car A6, who said that the car is not working again.
He drove it for two or three days and refueled in between (I hope he didn't put the same bad fuel in it as last time).

Today, I watched it again.
The same errors are stored in the engine control unit, transmission control unit, and ABS control unit as before, with the difference being that the engine still starts.

I then took a 20-liter diesel canister and, using a fuel pump from a motorcycle (BMW), I ran the engine directly from the canister. As soon as I give it gas, the engine runs unevenly and produces a lot of white smoke.

While monitoring measuring block 4 with VCDS, the target injection timing only matches the actual value at idle. However, the duty cycle of the injector control valve changes when accelerating, but as mentioned, the injection timing itself does not change.

I then adjusted the ESP (Electronic Spark Advance) so that it runs at approximately 8° BTDC (Before Top Dead Center) at idle. It also revs up normally without any load, but the actual injection timing still fluctuates slightly when accelerating.

Can someone tell me if, according to VCDS, a change in the duty cycle of the fuel injector adjustment valve actually indicates that the needle valve within the fuel injector adjustment valve is changing the cross-section of the inlet bore to the fuel injector adjuster piston? Or can you only say that it's being activated?

My diagnosis would be that either the solenoid valve (fuel injector adjuster) is stuck, or the fuel injector adjuster piston (cam ring) itself is faulty, or that the internal pump pressure is incorrect.

If I'm right about this, the question then arises as to why something is stuck. When I installed the pump, I drained the tank, flushed the lines/hoses, and replaced the diesel filter.

"I've also noticed something. When the pump is set to 8° BTDC (Before Top Dead Center) and I initiate the basic setting, it goes back to 0° late, and it also shows 0° early. Then, when I switch back to the measurement blocks, I have to press the accelerator a few times for the display to go from 0° back to the set value of 8° BTDC."

PS: It wasn't a new pump, but an exchange.

Then the replacement pump is probably also defective...

You can tell if something is happening by checking if the desired value matches the actual value, or if it doesn't. If the error is within a certain range, you could also try tapping into the cable and measuring the average voltage.

Was the pump new or used?

chli1976 wrote:

"Something else I've noticed is that when the pump is set to 8° BTDC (Before Top Dead Center) and I initiate the basic setting procedure, it resets to 0° late, and also shows 0° early. When I then switch back to the measurement blocks, I have to press the accelerator a few times for the display to go from 0° back to the set value of 8° BTDC." P.S.: It wasn't a new pump, but an exchange.

It's strange that it's showing either 0° before top dead center (BTDC) or after top dead center (ATDC), which could indicate a faulty knock sensor. However, that error should also be stored in the fault memory.
Or the (start of funding) shows the value because it simply falls outside the tolerance range.
I would also suspect a faulty pump.

The NHG (likely referring to a specific type of product or component) was replaced approximately three-quarters of a year ago.

Hi,

What does the MWB 18 code indicate about the condition of the fuel injection pump? And was the pump new or used? Thanks.

It was a bar-type pump.

I checked the MWB 18, and it's showing all zeros, so there seems to be no error.