A6 AEL: Won't Start After ESP Replacement

Hello everyone,

Like many other people, I have/had the same problem with the typical poor cold start performance at low temperatures of my AEL engine.
Adjusting the fuel enrichment setting didn't improve the situation because the ESP (Engine Stability Program) was malfunctioning.

Okay, I replaced the fuel injection pump with a used one. I set the start of injection to the target value (0.25mm) using a measuring gauge and tried to start the engine, but nothing happened; it wouldn't start.
Okay, I quickly found that error. The crankshaft was at TDC (Top Dead Center), but the camshaft wasn't.
Okay, so I set everything back to the original settings, reset the start time, and tried to start it again.
Well, that's no good, it won't turn on, nothing happens.

Interestingly, when you disconnect the fuel line to cylinder 1 and try to start the engine, diesel fuel sprays out.
That would indicate an incorrect start to the funding period.
After attempting to restart the fuel injection process, it no longer delivered any fuel through the line to cylinder 1.
Following this, there was a suspicion that the wing cell pump might be stuck, as the ESP (Electronic Stability Program) had likely been unused for a long time.

Okay, I disassembled the old pump (which I didn't really want to do), sealed it, and tried again. No, even with the sealed pump, the engine doesn't make a sound.
Attempts were also made to start the engine using jump cables, even with an increased voltage of 15.5V.
The engine isn't doing anything. The pump was pre-filled and bled, and diesel was also drawn from the filter into the pump.
I overlooked that when I bought the used ESP guitar.

Now I suspect that I may have made a mistake when assembling the ESP.
I noted the value of the throttle valve travel and verified it using VCDS before the first start-up attempt, and it was correct.
I'm not entirely sure if the position of the ESP's impeller is correct, as it can also be installed rotated by 180 degrees.

Could someone perhaps tell me what I'm doing wrong, or am I forgetting something?
The position of the aforementioned rotor disc is important so that I can also rule out this error.
I would be very grateful for any tips and tricks.

Best regards,
Christoph.

"Bleed off fuel from the ESP (Exhaust Gas Recirculation) system and, during the starting process, bleed all the injectors."

Thank you for the reply, it worked, it's running.
The only funny thing about it is that the start of injection is now precisely adjusted using a measuring instrument, but VCDS tells me "Injection start too late for display."

So, I'll have to keep checking and adjusting it until it fits, right?

Best regards,
Christoph.

Schweigi92 wrote:

Thank you for the answer, it worked, it's running. The only funny thing about it is that the start of injection is now precisely adjusted using a measuring instrument, but VCDS tells me "Injection start too late for display." So, I'll have to keep checking and adjusting it until it fits, right? MFG Christoph

Important for dynamic adjustment .
Pay attention to the coolant temperature .

Regards, Mpire.

Thank you for the tip.

Okay, the coolant temperature is now correct, but I was way off before.
I've been trying to adjust it in small steps to get it closer to the correct time, but I'm still not even within the tolerance range.
Adjusting the pump to set the start of the pumping process is not a common method, and it is generally discouraged.
Now I'm already getting annoyed by those long-necked guys.
I will now use VCDS to adjust the start of the boost and then measure it again because I'm interested in seeing what value I get.
Is it possible to install or assemble something incorrectly on the pump, which would cause the statically set value to be incorrect?

Best regards,
Christoph.

Possibly, the timing belt is misaligned on the pulley by one tooth...?