I have noticed that the diesel car idles high (1400-1600 RMP) in Idle. This is occasional and some times the engine check light comes on and goes off. scanned the system, but was not able to find any errors.
during the high idle, the engine sounds rough, and while accelerating, the performance is higher without any turbo lag but with huge amount of smoke.
does any one knows what the issue is and is there any proper cause for this issue?
I have a Tata Tiago and i encountered the very same problem about 6 months ago (my car was idling at around 2300 K). The guys at the service center ran all kinds of checks and diagnostics and came to the conclusion that there was something wrong with the accelerator sensor. So, they changed it. But it didn't make any difference. Finally, the electrician on the team popped the bonnet and started inspecting the wiring of the accelerator sensor from one end to the other. He found a patch on one of the wires where the insulation had worn off. As a result, the wire that was exposed was coming in contact with the metal body of the car, resulting in a short circuit. This was causing the sensor to malfunction. All it took was some insulation tape to cover the exposed wire and things were back to normal. Finding the patch were the wire was exposed did take some real effort, though.
