2001 Mazda Protege DX 1.6l engine sluggish when turning and won't start.

I just changed the timing belt and water pump on my friend's 2001 Mazda Protege DX 1.6l. I made sure the timing marks were all aligned for each individual cam and the crankshaft gear. I even turned the engine with a breaker bar a couple of times to make sure the marks stayed lined up. Took out a spark plug in cylinder No. 1 to ensure TDC, everything is perfect. But when I go to fire it up, even with jumper cables hooked up to his battery, the engine is really sluggish to turn like it's struggling. But I'm able to use the breaker bar to turn the engine fairly easily, with the usual resistance of the cam lobes you feel when you turn it. We took off the starter, took it to the parts store and they bench tested it and said it was okay, I checked for continuity in the power and ground from the battery, we even changed the oil because it was overfilled (he took it to Pepboys for an oil change and started noticing problems ever since, go figure). I'm just at my wits end here with this one.