Few questions, I have a year 2000 civic vti 1.6 dohc, it drinks a bit of petrol...

1. I have a decat so assuming my secondary sensor is missing, how does this affect the car and the mpg, or is it the 1st sensor that controls the fuel?

2. my 1st o2 sensor was replaced 2 years ago, 18k miles but my car burns a bit of oil so should i clean it? and if so how do i do it?

also any other factors to high fuel consumption? ... my driving style is economical, tyres are pumped up, brakes aren't binding, air filter clean. Bit of oil on the plugs just.

Cheers for the help folks

 

Only the primary O2 sensor contributes to the fuel trim.

Have you done an ignition system tune up - plugs, wires, cap, rotor, ignition timing?

Any CEL codes?

 

And you should also get the burning of oil fixed, that'll be he biggest thing to help it stop burning so much fuel

 

Havent had timing checked, and needs new plugs now as theyre caked in oil. No codes. The burning oil is my next fix, going to check PCV valve then get leakdown test done. Hope its not my piston rings, only smokes on changeover to vtec.

 

if it smokes under load, it's most likely rings.

 

Oil soaked plugs also point strongly to rings, or valve seals.

 

It doesnt smoke under normal load, just as it hits vtec i see in my mirror is puffs some out, cant tell the colour. ITs got 93,000 miles with full service history, services at 5k intervals. Hoping its just the seals and or PCV valve otherwise im not fixing it.