My wifes 850 has a no start issue. Turns over fine has spark at the plugs and fuel pressure at the rail. By passed the fuel pump relay to double check and still the same no start. Pinched fuel return line also but no start. Have not put fuel in cylinders yet to check if it would run momentarily yet. Checked for codes and none were listed

 

Hmm, you spark at the plugs and gas going into the engine but all it does is crank? Did you check to see if the timing belt broke? I can't think of any other reason why the car would not start at least for a couple of seconds.

 

If the timing belt were broken the cam position sensor would not detect the cam moving and would not allow spark. I might think that the fuel injectors are not firing.

 

I had a situation once where all of a sudden my T5 refused to start (it is always an instantaneous starter). I looked at everything I could think of, but still couldn't get it to fire. Then I read about this guy who had experienced this problem and he eventually got his 850 started by simply grinding away on the starter.

Not overly convinced I gave it a try and pulled the plug at about 35 seconds.

I was still stuck with a vehicle that wasn't going, so I was encouraged by one of the forumists into giving it another go. I fully charged up a spare battery and connected it to the one in the vehicle. I also took my wrist watch off and put it on the dashboard so I could get some idea of the time when, and if, things happened.

Then, full of determination, I jumped into the cabin and pushed the accelerator pedal hard to the floor and kept it there, then turned the ignition key and the car started to crank.

She cranked over for about 40 seconds then seemed to want to fire for about 5 seconds or so, before going back to the cranking over only mode however, it was either Sydney or the bush for me - so I kept the acceraltor pedal down and the key hard over and kept cranking. At around 80 seconds it started to attempt to fire once again and then, finally, the engine burst into action at around 85 seconds.

Apparently this being hard to start thing has something to do with oil getting under the hydraulic lifters and decompressing the cylinders - Tech would know more about this than me.

Also, I read in another post a person had taken about six minutes before their Volvo eventually fired up - so the starter motor in 850s must be pretty strong.

This may or may not be your problem, but it certainly solved a very mysterious 'no start' situation on my T5.

 

Well, look at it this way. A gas engine needs 4 things to start: Fuel, air, spark, and it all must occur in proper time. If you are sure you are getting fuel and spark, then the only other things that could inhibit a start are air and timing. If you are sure the timing belt is intact and did not break or jump time, then I would look for an obstruction in the air intake. If that checks out, then I would give the "crank it like hell" method a shot, as I too have heard in the past that it works on occasion.