96 grand cherokee 5.2 (sister's jeep). While she was driving the power steering pump blew up, causing the serpentine to fall off. She pulled over and shut the engine off before it died. I replaced the pump and belt but now the jeep won't start. It cranks slowly and makes a popping noise (release of compression?) through the exhaust. I have spark and fuel pressure to the schrader valve on the fuel rail. Battery is good, cables are tight and starter tested ok. Any input on what steps I should take next to diagnose?