525i 2002 Crank but No Start
I have a 2002 525i that will not start at times, it's been progressively getting worse. When it happens, the car will crank strong but not start. The strange thing is that when it starts, I can drive the car all day. On weekends, I zip around town handling errands, etc. Once it starts in the morning, it will start every time during the day. During the week, it also starts every time after completing my 8hr work shift.
This only seems to happen in the morning, the car will not start after sitting over night. Sometimes when it doesn't start, I need to wait about a week before I get it to start. Sometimes only after a few days and a few times did not start in the morning but was able to start it in the evening on the same day. The times when the car starts, it starts up rather quickly and strong on the first crank.
The car has 83k miles on it and is garaged most of the time, since this is my 2nd car. I put about 4k miles per year on average. I purchased the car used with 68k miles back in 2009 and was fine up until about 4 months ago when this intermittent problem surfaced. As mentioned, it's been gradually getting worse. Worse meaning, I need to wait longer before the car starts again. Even then, when it starts, I'm able to go all day without any issues starting throughout the day.
I'm no mechanic but willing to do my research to narrow down the possible causes. Once I have a good idea of the problem, I will then shop for a mechanic to replace specific parts. Too expensive for my budget to have them diagnose, I've been took before and decided to take different approach this time around. If simple enough, I can even attempt to replace the part myself, that it, once determining what's involved and deciding if I can do myself. I've heard similar issues with 95 model being either the Fuel Pump/Filter, Fuel Pump Relay or Crank shaft Position Sensor. Not sure if this would be a similar case for my 2002 model. Any helpful leads on identifying the cause of this problem would be greatly appreciated! -Martin