"There is no pintle in the prechamber. The pintle is part of the injector."-Danny

There is what we on this site have been describing as a pintle in the precombustion chamber. It is below the hole for the glow plug and is a rod across the middle of the precombustion chamber with a rounded section in it's middle... the purpose is to help break up the spurt of fuel from the injector... before it reaches the 5-7 radial holes in the bottom of the precombustion chamber....
In the archives you will find descriptions of people taking out the injector and looking down into the precombustion chamber and seeing only a little ball loose in the bottom... that is the center section if the rest of the rod gets burned away... and of course really messes with the tiny holes meant to spread out the fuel in the combustion chamber.
The only way to clean the precombustion chamber properly is to take it out of the head.
Greg