| Subject: | Rought idling |
| Question: | Anthony: Can you help me diagnosis this car. 2001 Mitsubishi Galant ES 2.4l,Electronic Auto Tranny This car us only working on#1 & 3 cylinders. Ihave check all wiring to and from cpu and are ok. I bench test all injecctors and they are ok too,I getting 12.7v at battery with engine off,12.6 with eng on, hot side of inject with key off i also get 12.6v with key on i also get the same v on ground side of inj with key on eng off. I swap around inj saying i may have miss diag them but the same thing happens only #1 & 2 cylinders are working. any assistance will be greatly appreciated. |
| Answer: | Brian, It sounds very strange that the voltage across your battery is actually less when the engine is running compared to when it's off. A voltage of about 12.7V is just about right when the car is off. But with the engine running, your voltage should be closer to 14V. That alone shows a problem with either your alternator or voltage regulator. Having both of those go bad on a car that's only two years old is almost unheard of unless those parts were dudds when the car was purchased. If swapping the injectors around changes which cylinders fire, that is very strange. You may have a faulty power transistor module or even damaged plug wires. You may want to try to use new injectors. If you do that, make sure you get injectors with a good return policy so you can return them if that doesn't work. Injectors are NOT cheap. If all else fails, have your car's computer checked out. It's
possible your ECU got fried some how. Again, all this is
rare for a car that's only 2 years old, but I've seen some
pretty strange things that people do to their brand cars. |