98 Volvo S70 Not starting, white smoke, popping

[roscoerich]

Hi everyone,
Well the black bat pooped out on me the other day at Starbucks. Will start once a day, run for a few then out again. Noticed at idle the engine was revving up and down. Cleaned the MAF sensor, throttle body, checked the fuel relay and still no go, so I changed the fuel filter which was long overdue. Engine is trying to fire up, but sounds like it's hitting real hard. Last attempt with a crowd of neighbors watching it started to fire up, then made a popping sound and shot the oil dip stick out and started spewing white smoke. Any suggestions on the cause of this? A little weary of trying to start it now in case I'm doing any further damage. Please, any advice would be greatly appreciated.
Thanks in advance.

[tryingbe]

Checking the basics? Fuel, spark, compression. Check the engine codes? Check the timing belt and cam timing?