I've seen harnesses where the cross wire the two injector outputs. I am sure that is why you are seeing one injector bank grounding the other.
Does the ECM have power?
If the ECM has power it will light the SES light key on engine off.
If it is getting power the ECM will turn on the fuel pump relay for two seconds when you first turn the key to on but don't crank. Note this test does not apply if the key hasn't been off for at least 45 sec so don't take alarm if it doesn't do the test in rapid succession.
Does the ECM get ignition pulses from the ICM?
After the ECM has passed the above two tests then just bump the starter. Don't crank it since that will close the fuel pump relay and confuse the test. Just turn it to crank enough to barely start to engage the starter. Since the engine turned at least 1/3 rotation the ECM should have seen an ignition pulse and the ECM should again turn on the fuel pump relay. The relay should stay on for two seconds and then turn off. If it does that then the ECM is getting ignition pulses from the ICM.
If the ECM is working, and is getting ignition pulses but not firing the injectors - It still could be a TPS problem. If the ECM is reading the TPS as 100% then the ECM is programmed not to fire the injectors. This is only during start up. Unplug the TPS to see if this is potentially the problem.
If none of the above then I would replace the ECM. Make sure you swap your PROM from the suspect ECM into the replacement ECM.
[This message has been edited by phonedawgz (edited 06-12-2014).]