Vitz 2003 Fuel Trims

[pwuser157677247953]

Hi, please look at the following figures and suggest what is causing -ive fuel trims.

*Horizontal axis represents RPMs

Coolant Temperature

[rajaatta]

Fuel trims are in -15 that indicates that your engine is consuming a lot of engine oil check for possible oil smoke and rectify as needed

[pwuser157677247953]

No oil reduction seen also by removing o2 sensor smoke test was done .. and thr was no sign of smoke.

[rajaatta]

Ok then reset the vehicle ecu by removing the battery wire and drive the vehicle for 70 kms on semi long routes.
Then recheck again and post the short term and long term fuel trims

[pwuser157677247953]

ECU was reset and after drive of 120KM on GT Road with 13Km/L fuel average.

[rajaatta]

Still -15 means a mis metering of fuel due to faulty fuel injectors or mass air flow

[pwuser157677247953]

Ok nxt i will chk fuel pressure and fuel injectors

[zakiuddin]

If it's common rail injection, Remove all spark plugs, prime the car by switching ignition to on without starting. Peek inside the spark plug holes and see if you can spot fuel leaking by an injector on top of piston head..
Or
Warm up the car, note the fuel rail pressure and switch off the car. Move the switch to on position and start noting the fuel rail pressure. It should double in next 5-10 minutes. If it doesn't, you may have a leaky injector.

[pwuser157677247953]

[Update]

Performed the following tasks:
1. Exhaust leak checking before o2 sensor
2. Injector leak checking nd cleaning
3. Fuel pressure regulator checking
4. Temperature sensor checking
5. O2 sensor checking
6. MAF sensor checking nd cleaning
7. Checking air filter assembly fr leak
8. Clean grips of o2 nd maf sensors wit contact cleaner
9. Engine compression test

and resetting ECU a dozen time after every step

Alkhmdulilah at last i got solved the issue today and it was loose intake manifold bolts due to which unmetered air was entertaining the engine.

Nw ltft is within the range of -3.91 and 3.12