2001 s40t engine turns over won't start

[kddcbw1963]

Purchased a 2001 Volvo S40 with 190,000 miles, car ran fine for a couple of days, then the car overheated, added water and used blue devil to seal heads. I know this is a temporary fix, but seems to be working, compression is good with no water or antifreeze where they shouldn't be. My problem now is my car won't start, the engine will turn over but won't start. I have replace the coils and spark plugs and I got the car started, but after it sat overnight, it won't start again. I cleaned the cranking sensor and the car started, after I drove about 5 to 10 miles and let it sit for an hour, the car wouldn't start again. So, I replaced the cranking sensor and the car started right up, Again, after sitting overnight the car wouldn't start again. I read other forum questions on this site and it seemed like others that had the same problem needed to replace the fuel pressure regulator. So I went and borrowed tool to check pressure, I researched and found PSI should be about 0.044 (??), check that and my PSI was about 0.055. Should this pressure go down after I turn ignition off, logically it seems like it should after the fuel pump is turned off. Also my battery is about 5-6 years old and keeps drainging everytime I try to start, quickly also, I know I should get a new battery. Was wondering if weak battery could effect starting of my s40 and if the PSI is correct for FPR? Please if anyone can help I would greatly appreciate any information. I have been a mechanic for over 30 years professionally and hobby and my dad has been a mechanic for over 60 years and still at 78 years old works and on cars, but both of us have never worked on Volvo's. He seems to think its the computer, also the cigarette lighter, charger outlet has been pull out of console hole, I was told if this is out of console hole, computer has been out because wiring harness is so short it pulls on plug. Could the computer be causing my car not to start?

[alschnertz]

I believe the fuel pressure should be around 44 psi. Maybe you're reading the scale wrong.
The fuel pressure will eventually go down after shut-down, but should come back up to that 44 psi shortly after cranking.

As for the battery, modern electrical systems are more sensitive to battery voltage and amperage. Not saying you should go out and buy a battery, but maybe you could put yours on charge or borrow one from another car while you're testing.

[kddcbw1963]

Thanks for the info, but I can't get car to start to see if psi will go back to 44. I was told if the batter is old it could be causing the problem.

When I purchase a battery, what should the cold cranking amps be on the new battery. I have been told this has a lot to do with the car not starting. Thanks.