Chrysler Repair: 1990 6 cyl 3.3 L runs when cold, stumbles when warm, coolant temp, volt ohmmeter

Question
I have a few questions. My cars starts and runs until it gets warm. Then it acts like it is flooded out. I have checked the fuel pressure and it is 45 to 50 psi. I have checked a lot of things. I checked the codes that it throws (this time it is 27), and it says injector control problem, but what does that mean? I have tried about everything I know to look for, so help me out. Thanks. Carolynn

Answer
Hi Carolynn,
Except for the code I would suspect that the coolant temp sensor is not changing resistance as it gets warmed up. It should read 7-13K ohms when cold, and gradually drop to 700-1000 ohms when the engine reaches 200F. If not, then change the sensor. The code 27 means that one of the three injector circuits doesn't exhibit the normal impedence kick that it should every time it is pulsed. This could be due to a faulty injector (staying on). The circuit could be open or grounded, an injector could have failed with its circuit open, the ASD voltage to the injector bank could be open, or the powertrain controller could be failed. There are a number of tests that can be done with a volt/ohmmeter to check out which of those is the reason. But check the coolant sensor first before going through all those tests.
I would wonder why it would work fine when cold, if it were the injector circuit. I can give you some ideas on how to check the injector circuits if necessary.
Roland