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Latvia, Riga
1 Level
720 Review
64 Karma

Review on πŸ”₯ Denso 234-4741 Oxygen Sensor: High-Performance Solution for Efficient Fuel Combustion by Melvin Belton

Revainrating 5 out of 5

Replacing the O2 sensor makes an amazing difference in fuel economy!

My 20G Evo 9 2.3 liter stroker with 20G Turbo lit up from time to time, especially in traffic. The code was P0170 Fuel Trim Bank 1 / Faulty fuel system. My LTFT fuel trim was +25% so the warning light came on. This indicated the engine was running lean but at WOT there was a huge puff of black smoke coming out of my exhaust indicating it was rich. Further examination of my spark plugs found them to be cakes of black soot and dry carbon, again indicating they were very rich. My bumper was also covered in exhaust stains. My knock sensor also flashed sporadically when accelerating. I've read that detonation can also occur in a "too rich" scenario. My range with a full tank and relatively light foot was 300-320 km (6.5 km/l) with 70-80% highway and 20-30% city approach. Stop the movement. Turbo spools from time to time but never over 4k RPM. I then installed AEM UEGO Wideband to make sure I was rich and not needy, and indeed I was. Smooth acceleration would read 8 or 9 AFR on 98 RON and even while cruising on the freeway I couldn't get better than 11 or 12 AFR. I then decided to change the O2 sensor and lo and behold, on my second full tank I got 390 km (8.5 km/l) before the 'empty' light came on. I could easily drive 400km before the lights come on. My riding style hasn't changed and I was still shifting between 3,000 and 3.5,000 rpm. AFR at WOT will now read 9-10 and in cruise it will now read 13-14. The part number is correct on the sticker on the Denso box, but the numbers engraved on the sensor itself are different. Compared to my old sensor, the numbers were also different (not sure if the old one was changed from the factory or before). But the thread and length matched perfectly, there were no problems. The warning light is gone and my knock sensor is now picking up a lot less bumps.

Pros
  • So far satisfied
Cons
  • Write later