I have a 1999 Volvo S80 that has sat for about 3 months with a dead battery. now the car will not start. the starter turns and cranks the engine but it will not fire. the compression is good in all cylinders and has fuel pressure of about 50 something PSI.

 

What are the compression numbers?

 

If it is the immobilzer it should reset over night.

 

Ya know, Kent, I'm sure he appreciates your input, but if he hasn't figured it out in 7 1/2 years I bet he's given up on it and just doesn't care.

Just a guess on my part.....



PS - the immobilizer prevents the car from cranking. The OP's car cranked.

 

Do you know if you have spark? Does the sun roof open and close? If not then it may be the siren. Mine was full of water and corroded. I think I just unplugged it and the car started, but I may be wrong about that. If it is a security issue with the siren the sun roof won't work. Hope this helps.

Another strange issue I had was with the battery to the starter. I put a 2 foot cable from the starter to the fuse box in front of the engine and the car starts much more reliably. I can't tell you why, but it was two years finding that solution. The battery in the trunk appears to be that problem.

 

Yep, I am leaving. Thanks for pointing that out. I just answered him again. Hell, I was looking for answers myself so maybe the things I wrote will help someone else. Sorry to wake you up.