I sent my PCM off to get unlocked, got it back and now the #3 injector is reading 15.00 on the balance rate, and has a pulse width of.900. Before I sent it off everything was running fine, had a surge at 1900 rpm going down the highway. Now it is missing out at all rpm's, and the number 3 injector isn't firing. How can I chrck to besure this injector is bad before I tear into it? Seems like just changing the computer shouldn't do that. I don't believe in coincidence that the injector went bad between starts. No mods....

 

When I accelerate the balance rates all go to zero. The average balance rate is -2 to +2 except number 3 which is 9.6

 

sounds like a clogged or stuck injector.

+15 is what it will be if no fuel is getting into the cylinder and the ECM is trying to increase the fuel to balance the idle.

anything more then +-4 in park and +-6 in drive is considered bad. the balance rates will only show when you are not moving and no throttle input, ie: while idling.

i have heard of some people, my self included, clearing stuck or clogged injectors by commanding max fuel psi for a short bit while idling.

doing the GM injector cleaning procedure wont hurt ether.

 

My ECM came back damaged.

 

glad you figured it out. while it didn't seam likely i guess it is always a possibility.

 

Yeah, I didn't think something like that would happen. Of course, I didn't think to write the serial number down as it didn't cross my mind that they might send me a different one. I'm really stinking mad about it. Paid them to ruin my computer.