BMW: E34 / 530i 6 cil. starting problems, fuel pressure regulator, vacuum line

Question
Hello Josh,
As you say you have a lot of experience with the 6 cil. enigine and I have a question about my 1988 BMW 530i automatic. Since a few months it is having starting problems. In the beginning when it has been still for a week or longer, then after a few weeks it was having starting difficulties after being still for a few days and recently after a day it allready is having troubles starting! The trouble is that I have to start and start and it gives some pufs from a singel cilinder and sometimes after 5 or more minutes of (interupted) starting it starts running on 3 or 4 cilinders and after 10 seconds the others start running too and then it suns completely smooth! During the drive it does not have any trouble at all. The starting problem is not really influenced by the weather. It occurs when it is cold (minus 5 celcius) or when it is nice spring weather (plus 8 with sunshine) so, what could be causing the problems? Thanx!Guurt

Answer
Guurt,
 This is nothing out of the ordinary, either your plugs are not firing good, or your injectors get gummed up after sitting.  I would check the distributor cap to make sure there is no condensation on the inside.  Sometimes a small crack or hole will let water inside and it will cause problems with firing.  If that checks out ok, it could be the injectors gummed up from sitting.  You can try some injector cleaner that you put in the gas tank, these work most of the time.
 there is another procedure called a "Hot-Soak".  I see that you are overseas, so I dont know if you can get this product.  It's called "Seafoam", it's a mineral oil, that cleans the inside of the cylinders and the injectors.  you can put this into the gas tank to clean the injectors as well.  To do the "hot-soak", get the engine up to operating temp and then remove one end of the vacuum line running to the fuel pressure regulator.  Put this end into the can of seafoam and let the engine suck this cleaner up.  Once about half the can is removed, cut the engine off and let it sit for 5-10 minutes.  The heat and the cleaner will remove all of the carbon deposits on top of the piston and clean the combustion chamber.  After letting the engine sit, start the engine again.  This may take several tries, but it will eventually start.  When it starts it WILL smoke some, so dont be alarmed.  This will continue smoking for about 10 minutes while it blows all the carbon out of the cylinders.  
 I have done this and it makes the engine run much smoother afterward.
 Hope this helps,
 Josh