Expert: Sean Halliday - 12/27/2008

Question
i have 90 lumina 2.5 that stared running on 2 cylinders 1&4.removed and replaced crank postion sensor, module and coil. reinstalled. now i have no spark on any cylinders. checked continuity of wires to module, ok. replaced ecm. checked all fuses, ok. still no spark. found i have no voltage to bypass wire at ignition module, sould be 5 volts. any idea of where to look next?  

Answer
Check ignition relay and all fuses.Its nearly always the ignition module that goes bad but if you changed that then back track from the module and look for bad connection or broken wiring.The fact it went on 2 cyls tells me its bad wiring.Look at connectors in the loom where the wires come through the firewall.If all looks ok then you will need a wiring diagram and start with the pcm to check each pin and continuity on each one.