I looked and cant find any timing marks. Do I have to pull the engine to check?

*Update* I have replaced the crank position sensor, and wrapped all starter power lines with aluminum foil. also checked for spark: positive. fuel injectors: positive. the computer is giving no engine/mechanical related error messages. It cranks just as fast, but only cranks for about 10 seconds or ...

***Update Okay After getting a new battery it cranks much faster. Probably normal speed now. IDK So I made a video. But no luck. The tach still jumps so Tomarro I am going to replace the crank position sensor. Here is the video. You can see at 1:09 it backfires. I was hitting the gas. at 1:36 you ca...

Hello, New here. I recently bought a 2000' S80. I bought it in hoped of making it run. However I am getting quite I head ache, and this forum seems to be the best place on the web. 2.9 NON turbo. When try to start the engine, it spins SLOW. So I tryed to turn over with NO compression( spark plugs ou...