Q: My s80 cranks but wont start.

Check carefully under the hood to be sure there are no air large air leaks in the intake system, such as the big boot at the throttle body or any other large vacuum hoses. Sometimes these rubber parts fail and the resulting air leak is enough to keep the car from running. Since you say you have already tested the fuel pressure, the next move would be to hook up a scan tool and read the codes. Two common failures that would cause a no start and would show up in the scan would be a crankshaft position sensor or an ignition module. Resist the temptation to simply replace one or both of those parts until the problem can be verified, however as there are other possibilities and you don’t want to spend money on parts that you don’t need. By contacting Your Mechanic, you can have a technician come to your home or office to diagnose your Volvo and let you know just what it will take to solve your problem.