Q2 have a 2000 9100 ism has low voltage at fuel pump and evm will not power up to read codes it has 2.7 at pump with everything off and 8.7 with key on have all ready tried a different ecm same problem.
At key on, you should get the yellow "CHECK" , or "WARN" engine light along with the red "STOP ENG" light coming on for a bulb check. These lights are actually turned on and powered from the ECM. If these lights do not come on then your ECM is not powering up, or not getting ignition power at key on. Check your main ECM power fuses. There are two possible locations. The power harness either feeds off of the positive post on the starter, or they come from the batteries. So the fuses will be near either the starter or at the batteries. Should be two of them, usually 15 amps each. Check for good 12 volts and follow the harness as best as possible to the ECM and inspect it for any bad spots. There is usually another connector or two along the way, especially if the harness is direct from the batteries. If your warning lights do come on then I would suspect a harness problem to the pump solenoid.