I have a 92 Lt-1 and with key in the off position, when using a test light to 12v and placing the lead on either side of the connector for a single fuel injector the light comes on. This only happens on the right bank of injectors. This bank also pours fuel into the cylingers. what's going on? any help is appreciated

 

I think 12v is applied to one side of all the injectors [key on but not running] and each injector is activated through the computer by applying ground to the other side of the two wires that go to each injector. Sounds like you could have a short in that side of the harness if you 'see' ground on all of them on that bank. (can't find my schematic for the computer right now though)

 

This is speaking from a L98 perspective, but I can't imagine that the LT1 is much different as far as the basics are concerned.

The injectors have 12 volts on them from the INJ fuses (one for each bank). Normally you would ground your test light and see it light when you connect to both sides of the injector connectors. The reason for this behavior is that 12 volts is connected to one side of the injectors. The ECM grounds the other side of the injector to turn it on. When the engine is not running that ground connection is open and there is no current flowing in the injector circuit. With no current flowing there is no voltage drop across the injector and that's why you see 12 volts on both injector wires (with the connector on the injector). When you disconnect the connector from the injector you will see 12 volts only on the INJ fuse side (you have to disconnect all the injectors on that bank to see this -- otherwise you're seeing the connection through the injectors that are still connected).

Going by your description (connected test light to 12 volts and it lights on both injector wires), you have a short to ground in the injector circuit. Either the wiring between the injector and the ECM is shorted to ground or there is a short inside the ECM (probably the injector driver for that bank is shorted). You can test for a short in the ECM by disconnecting the connector at the ECM and again probing the injector wires. It's possible (though unlikely) that you have a shorted injector. To check for that unplug all the injectors on that bank and probe the connectors.

Also, the only way you could get a light on both wires (with the test light connected to 12 volts) is if the fuse for that bank is open or the wiring between the fuse and injector is open (assuming there is 12 volts on the fuse). You can test the fuses by grounding the test light and probing both sides of the fuse (there are two small holes in the top of the fuse that you poke your probe into). The light should come on for both sides of the fuse (ignition on, of course).

 

A noid light is much better for testing power to the injectors.

 

Thanks to all who replied to my 1992 fuel injector electrical issue. The ECM was Bad. I replaced it with one out of a 93 Camaro. I put the FPROM from my Bad ECM into the Camaro ECM and all is well.