Hi everyone. I have a cat 320D. Serial is CAT0320DABZP02215. The problem is that the machines rpm itself goes up and down even in idle position. I have replaced all the filters. Replace all injectors. The fuel pump is good. The rail pressure is 495kpa. There is no error code. The machine all functions work well but only problem is the rpm ups and down
Thanks for the bit of information that you have posted, few questions: Did you or someone else have ET hooked up to decide you needed the injectors. Have you checked all battery connections to the ECM along with the grounds ( Do you know how to test computer ground ) ? What is the state of your battery box and machine in general. How many hours on the machine. Have you tested all the frame grounds, cab grounds monitor grounds, engine block to where ever the cable goes ground. Do you have schematics for the machine. Do you know how to check for Alternator output and AC Ripple voltage. There is a lot of possible problems, do you have a quality multimeter.? Maybe tell us more about your tests so far. Maybe post a picture of your dash, monitor. Simon C