Occasionally while driving my 2000 Skoda Octavia the engine stop, revs fall to zero, the “no-charge” indication lights up and a piercing sound signals a NOK situation. Consequent attempts to start up the engine see the starter crank, but the engine won’t fire. After some minutes and only when the “heating plugs” indicator appears the engine miraculously starts. Any ideas how to approach?
On the surface, it sounds like the electrical system is somehow letting you down, Todor. The no-charge light comes on because the engine has stalled and is not driving the alternator, so that’s probably not the root cause here. But only when the glow-plug light appears (which it should every time you turn the ignition on ready to crank the engine) will the engine fire. That’s the clue that whatever glitch is at work here has settled down and is allowing the electrical system to work properly. Of course, a diesel engine doesn’t have a spark (electric) ignition system, so we could be barking completely up the wrong tree here. That said, the modern diesel engine does use a series of electric fuel pumps, and a faulty pump could easily cause the problem you’ve described.
With that in mind, the absolute best advice is to take the car to a workshop with the necessary diagnostic gear and have the car scanned to see what fault codes it coughs up. Until you do that, and can isolate the problem, you can run around in circles for months changing perfectly good components in a costly process of elimination.