Intermittent starting problem - 2000 V70XC

[tmounib]

Dear Volvo owners.
I had very hard time finding a logic answer for the hard to start when cold problem
I been reading many many many posting regarding this problem but no one (( I MEAN NO ONE )) ever really came up with solid answer on how to resolve this headache.
I am not a mechanic but I analyze everything in logical way and I think I might find a very good answer (hints) to resolve this nightmare and help others.
I bought 2001 V70xc with about 190Kmiles and it came with hard to start (specially when cold ) problem, I did the usual things , Tuneup, plugs etc, etc,
Next day same problem,, came on line and start to read,, you tube, every available resource and still no luck.
I even replaced the ignition coils and still no difference
Finally I start to go little deeper in the problem which is the spark plugs ,, every time I rook them out they are fully covered with soot,, not light coat but a lot.
I realize it is RICH running issue, too much gas, less air and did every possible vacuum leak test you can think of, everything is tight. now time to think more about the gas, the supply, the fuel pressure and related matters. I started with the filter was unusually heavy (after I drain the gas from it) which indicate tons of dirt inside, then checked the fuel pressure at the fuel rail during running engine it was 55 PSI , Next day start fresh early morning,, fuel pressure is ZERO when the car is cold,, turn the ignition on and the fuel pressures remain ZERO. ,, I even changed the antenna ring, no luck still.
back to the wiring diagram and replaced the fuel relay under the dash board ,, now I got about 40 PSI when the ignition is on but still hard to start,,
My last resort was the readjust the fuel pressure and the idea came from watching something related on YouTube
I purchased ((ADJUSTABLE FUEL PRESSURE REGULATOR)) from EBAY, under $20.00 and for extra assurance I purchased in-line CHECK VALVE for $6.00 from ebay
that was the answer for my problem,,
Damn I hit it right,, after 4 months of searching and trying different things ,, OMG what a release
Please review the attached pictures and see what I did,, that might help the next V70xc with a headache (NO START ) owner
Good luck