Alright I am getting desperate. I have been having idling issues, and have combed through literally all the threads on the issue on this forum but have not found a solution. I will start by giving a description of my car, followed by what steps I have taken to remedy each idle issue I have faced.
Initial Car Description:
- 05 Facelift DC5R
- Owned for 5 years
- Spoon 421 header
- Fuji mid-pipe and muffler
- Stock airbox
- Stock throttle body and sensors
- No tuning
Problem 1 (3 years ago)
- Idle hunting+checklight
- remedied by changing with a second hand throttle body and second hand TPS sensor
Problem 2 (2 years ago)
- Changed stock airbox to mugen
- Checklight on.
- Attributed to primary O2 sensor. Seems that it could not 'keep up' with new intake characterstics
- remedied situation with new primary O2 sensor
Problem 3 (1 year ago)
- Idle hunting
- TPS seemed to not be able to hold lower bound voltage
- Changed TPS to Ktuned V2
- Cleaned TB, IACV
- Problem cleared after ECU reset
Problem 4 (0.5 years ago)
- Rev hang on cold start, rev maintains around 1200 after warm up, sometimes reverts back to normal 800-880
- Checked IAAV, no blockage
- Checked ECU wirings, all OK
- TPS holding voltage
- No audible/visible air leaks using carb cleaner
- TB and IACV removed and cleaned
- ECU reset and coldstart was ok for the first day, but after a day of driving, above symptoms returned
- Changed Spoon header back to stock as the location of the primary O2 sensor is slightly different, and the Spoon header doesn't have a cat like the stock header setup.
- ECU reset, ok for the first day of drive, problem returns after.
- Bought new IACV (2 weeks ago)
- Problem persists
Current Car Description:
- 05 Facelift DC5R
- Stock header
- Fuji mid-pipe and muffler
- Mugen airbox
- Stock throttle body, Ktuned V2 TPS sensor, new IACV
- No tuning
What's next?
- As you may agree, I have done quite a fair bit to sort this out. My engine is healthy (getting about 10.8km/l mileage on average), with 130,000 km on the clock.
- The throttle body does not seem to have any leaks, and I have stopped short of buying a new one for about 600 quid ($1000+ in my Singaproe currency)
- My mechanic is at a loss of how to remedy the situation and postulates it may be ECU related and the chip controlling idle is faulty
- He has proposed I borrow another stock ECU to diagnose, but I have never ever heard of swapping out an ECU. The only modification I have to the ECU harness is a lead to my RSM, so it's practically undisturbed. Can repeatedly resetting the ECU take a toll?
- I have had large periods of good idling with the Spoon header and Mugen airbox, and I would think the ECU should be able to compensate for the AFR in these conditions.
I would appreciate any input in solving this. Thanks in advance.
Initial Car Description:
- 05 Facelift DC5R
- Owned for 5 years
- Spoon 421 header
- Fuji mid-pipe and muffler
- Stock airbox
- Stock throttle body and sensors
- No tuning
Problem 1 (3 years ago)
- Idle hunting+checklight
- remedied by changing with a second hand throttle body and second hand TPS sensor
Problem 2 (2 years ago)
- Changed stock airbox to mugen
- Checklight on.
- Attributed to primary O2 sensor. Seems that it could not 'keep up' with new intake characterstics
- remedied situation with new primary O2 sensor
Problem 3 (1 year ago)
- Idle hunting
- TPS seemed to not be able to hold lower bound voltage
- Changed TPS to Ktuned V2
- Cleaned TB, IACV
- Problem cleared after ECU reset
Problem 4 (0.5 years ago)
- Rev hang on cold start, rev maintains around 1200 after warm up, sometimes reverts back to normal 800-880
- Checked IAAV, no blockage
- Checked ECU wirings, all OK
- TPS holding voltage
- No audible/visible air leaks using carb cleaner
- TB and IACV removed and cleaned
- ECU reset and coldstart was ok for the first day, but after a day of driving, above symptoms returned
- Changed Spoon header back to stock as the location of the primary O2 sensor is slightly different, and the Spoon header doesn't have a cat like the stock header setup.
- ECU reset, ok for the first day of drive, problem returns after.
- Bought new IACV (2 weeks ago)
- Problem persists
Current Car Description:
- 05 Facelift DC5R
- Stock header
- Fuji mid-pipe and muffler
- Mugen airbox
- Stock throttle body, Ktuned V2 TPS sensor, new IACV
- No tuning
What's next?
- As you may agree, I have done quite a fair bit to sort this out. My engine is healthy (getting about 10.8km/l mileage on average), with 130,000 km on the clock.
- The throttle body does not seem to have any leaks, and I have stopped short of buying a new one for about 600 quid ($1000+ in my Singaproe currency)
- My mechanic is at a loss of how to remedy the situation and postulates it may be ECU related and the chip controlling idle is faulty
- He has proposed I borrow another stock ECU to diagnose, but I have never ever heard of swapping out an ECU. The only modification I have to the ECU harness is a lead to my RSM, so it's practically undisturbed. Can repeatedly resetting the ECU take a toll?
- I have had large periods of good idling with the Spoon header and Mugen airbox, and I would think the ECU should be able to compensate for the AFR in these conditions.
I would appreciate any input in solving this. Thanks in advance.