ESP Issues: Troubleshooting and Solutions

Hi everyone,
We had a fault code 550 (regulation deviation...) on our Golf 3 TDI with the AFN engine, 110 hp, and 170,000 km. Following the excellent guides here on the forum, I searched for the actual fault and eventually found the injector pump. The plunger was damaged on one side. After a long search, I bought a new ESP (Electronic Servo Pump) and finally installed it last night. Everything went well so far: assembled, adjusted approximately to the old position, bled, and it started. Now, here's my problem: After a short warm-up phase, I turned off the engine to correct the injection timing by rotating the ESP. But it didn't work. I can't get the car running again... Does anyone have a tip? I also have a diagnostic tool, but it doesn't report any errors. What could it be? Can a diesel engine 'flood'? I thank you in advance for your helpful answers! And by the way... A big compliment to your forum; you rarely find such willingness to help these days... many VW workshops could learn a thing or two from you...!!!!

Hello, Bubbes!

You reported that the engine started running immediately after the ESP replacement. However, the machine no longer starts after the ESP is rotated.
Have you tried reverting it to the old position? I suspect you might have adjusted the ESP in the wrong direction (probably "late").
Was the starting point marked? If so, it should be easy to restore that position.

Why did you actually adjust the pump? What was the injection start setting in the basic settings mode in VAG-COM?

I'm just mentioning, based on my own experience, that even a slight rotation of just a few tenths of a millimeter can cause a noticeable change in the injection start. If you've rotated the pump, for example, just a fraction of a millimeter in the wrong direction, that could be the cause of your starting problem.

Quote:

Can a diesel engine also "flood"???

No! "Flooding" in gasoline engines is primarily caused by a "wet" spark plug, which prevents the spark from firing.

Good luck correcting the pump timing!

Regards,
Alex.

Unfortunately, I didn't mark the spot. But I'll try again later. Thanks.

Hi,

Basically, I would double-check the synchronization of the camshaft, pump, and crankshaft. If that's correct, the engine will run.
But the best way is to manually rotate the engine again by turning the crankshaft bolt.
Then, manually fill the pump with diesel, which will save you from having to crank it repeatedly, and don't tighten the pump yet.

You should now be in pairs. One person starts the engine, and the other presses against the pump as hard as they can. They should push the pump towards the engine while the engine is running.
Then the engine should start eventually.

Greetings.
Thomas.