Chrysler Repair: check engine light on, orange wire, engine controller

Question
I have a 94 duster 3.0. The check engine light went on and the code came up as the o2 sensor. I replaced it and the light went away. Two days later it came on again, now giving the code 27, injector control circuit. In the morning the light is off, after about 20 minutes of driving it comes on again. When it does, it idles/runs a little rough. It never dies. I'm running some injector cleaner through it in hopes it will help. Any suggestions or tips would be apperciated. The light is driving me crazy!
Thanks,
Tony

Answer
Hi Tony,
I believe the reason that the engine idles rough when the light comes on is that the controller enter a "limp-in" mode where instead of running on the basis of all the sensors it shifts over to running on pre-determined parameters that are just designed to keep the engine running. I would be inclined to check the wiring harness: from the pins on the plug at the end of the fuel rail to each of the injectors, and from each injector pin to the pin for the common 12v supply wire (dark green/orange) at that same plug, and from the other side of that plug back to the SBEC (engine controller) in order to make sure that none of the wires or injectors is 'open' or "shorted". The colors for the injectors are: #1 white/dark blue, #2 tan, #3 yellow/white, #4 light blue/brown, #5 gray, #6 brown/darkblue, and they connect to pins 16,15,14,13,38, and 58 at the 60-way plug of the engine controller, respectively.* The way the injectors work is that 12V is supplied to all the injectors from the autoshutdown relay via dark green/orange wire at the injector harness, and then each injector is grounded momentarily by the engine controller using the 6 different wires, in turn, as the engine rotates. If one of the injectors or its wire is "open" or "shorted" to ground that would likely set off the 27 code. So measure the resistance from each of the pins on the 60-way to each of the injectors, and also measure the resistance across each injector to see if you can identify one of the six circuits that is different in resistance and thus check its wiring or the injector more closely. With all those wires being located above the hotter parts of the engine, one of them may have melted its insulation and thue be setting off the code. To identify the pins on the 60-way plug, hold it horizontally with the pins facing you, (short tab up) and count from left to right of the top row(1-20) then cycle back to the left for the middle row (21-40) etc.
That is my best advice if the cleaner doesn't do it.
*To identify the actual pins on the 8-way plug at the harness for the injector's connector, find the corner pin that is for the common dark green/orange wire by measuring from each of the four corners to one of the injector plugs for that wire. Once you have id'd that pin, injector 1 is at the diagonally opposite corner, and goes along that side of the plug to injector 4, then diagonally accross the plug for injector 5, and 6 is adjacent to that. There is one pin (between 6 and the common 12V line) that is not used.