Usually most of sentra have almost 25~30 MPG. Maybe 20 miles even if pretty bad one.
I expect mine is too. But…
It’s almost 11 miles per gallon. Surely somewhere is wrong particularly fuel system or delivery parts.
I have to do something for that.
So, I decided to change Spark plugs and O2 sensors by myself. I thought labor is too expensive considering difficulty level of work. And very easy to find “how to~” guides.
▲Bought parts on eBay and Amazon.
- NGK Laser Platinum spark plugs
- NTK Oxygen Sensor
- Lucas Injector cleaner
And I realized the biggest problem remained. I don’t have any tools. -_-;;;
So, ordered some tools and air filter too.
- 5/8” spark plug wrench socket
- 7/8” O2 sensor wrench socket
- 10mm wrench socket
- Socket extension
- Denso air filter
▲Here is my engine. Let’s start spark plugs first.
▲Install new one
Spark plugs change done.
Engine light does not on at that time.
But I want check these O2 sensors are really work. So, connect output terminal of the O2 sensor to multimeter and check voltage level.
The result is
I thought problem is two downstream sensors’ failure. after this work, engine check light on suddenly…-_-...
Anyway I'm not surprised by that because I already knew something wrong with O2 sensors. Even, I expect that code makes me sure my analyze.
So, I tried to read OBD-2 code using by “pedal dance” and found two codes.
- 0031 (Heated Oxygen Sensor (H2OS) Bank 1 Sensor 1 problem or circuit)
- 0051 (Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 problem or circuit)
O2 sensor’s fuse was good. That means, both Up stream sensors are in trouble.
“Ok, let’s replace up streams’ first.”
Sensor 1 (up stream) s are blue wire and black wire.
▲Remove old sensor
▲Unboxed brand new sensor.
▲Replace left sensor was interrupted by cable guide. So remove guide.
Ok. OBD-2 codes are solved.
▲Refilled engine oil ; Castrol 10W40 part synthetic
Fill up 3 Gallon when gas gauge mark on “E”. Reset an odometer as well.
Ok. It’s done.
So, Total cost was
NTK 24573 and 24645 O2 sensors cost are $ 141.26
Except these two sensors, actual total cost is $ 254.82
All these for $254.82. sounds not bad.
- Replace two Upstream Oxygen Sensors (NTK 24297 & 24298)
- Replace all spark plugs (NGK Laser Platinum)
- Replace Air filter (Denso)
- Put Injector Cleaner (Lucas)
- Refill Engine Oil (Castrol 10W40 part synthetic)
I've never done this before. even didn't know how to change Engine Oil. but I’ve done a pretty good job.
Thank you so much for all of your help. thank you guys.
Let’s see what happen next.
Solved Problem!!!!!!!!! ▼
Last edited by white glove; 06-20-2011 at 09:54 PM.
most of the time its just fouled spark plugs and a dirty airfilter that will reduce your mpgs, that and driving habits.
Hope you had fun.
"Be polite, be professional, but have a plan to kill everybody you meet." General James Mattis
That oil I think is to thick. I would have stuck with what is recommended; 5w30.
Can anyone read spark plugs? I wonder what story yours will tell. Also did you index your plugs? As in, have them all facing the intake side.
If you want to run 40 weight, then get 0w40. Mobil 1's 0w40 has some of the highest zinc and phosphorous at 1100 and 1000 ppm.
your plugs looked just fine. the tips had good color, now if they were dark brown to black i would have been worried but yours looked almost lean.
your real problem was that you drive a gxe/1.8 hahaj ust kidding man. damn nice right up and way to go with jumping in and doing your own work! i bet you felt great when you were done.
Last edited by superspec; 06-24-2011 at 03:37 PM.
4 o2 sensors???? holy crap
Very good write up. And that oil should be fine, but I would personally go for 10w-30--if you're not burning any oil. It could save you an mpg or two.
Become the Master of the Sixth Speed.
2006 Nissan Sentra
171 HP • 190 LB-FT • 14 Mods
Modifications - Exhaust (4), Suspension (3), Tireswheels (2), Drivetrain (2), Air Intake (1), Brakes (1), Ignition (1)