So I’m having trouble starting my 2005 Honda s2000 with 125k miles. The fuel pump is priming, checked all the fuses and the timing seems fine. Did a compression check and all four cylinders are low. Cylinder 1 and 2 and 4 have 100. Cylinder 3 has 0 compression. Also the car is getting weak spark, but recently I just changed the plugs and coil packs, so they are pretty new. If anyone has any ideas please let me know. Thank you!

 

Would check valve clearance

 

I'd do a leak-down test, on all 4 cylinders.