CamsX

Hello, I've decided to create my own thread, since I haven't been able to find one that refers entirely to my problem.

To go straight to the point, I believe my car is consuming a lot more fuel than it should. I am not able to reach 300 kilometers (not miles) on a full tank of city driving. What would you suggest I should check in order to improve this?

Ok, feel free to skip the long story below.

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I got the car back in May, as I wanted a fun car to daily drive to and from work. I live 10 minutes away from work, but if the traffic is heavy it can become a 25 to 30 minutes commute. The car is a 2005 AP2, which I'm pretty sure has a salvage title in the USA (haven't paid for the carfax report), but that's usually the case with most sport cars imported to my country that were never sold here at the dealership, so I'm ok with that.

With a little bit over 40K miles, it has several things done on the cheap side which might be affecting it. I've changed the oil and sparkplugs, cleaned the K&N drop-in filter, and done other things not relevant to the engine. It has a very crappy ebay exhaust and an even worse custom test pipe, which I will be replacing with a Berk HFC asap. Once I save enough I'll be getting a Tanabe Medallion Touring exhaust and a new Clutch kit, as I don't know what it was done to it, but it has a hideous buzzing sound on decel.

I park my S2000 on a small hill outside of my garage, so it stays under the sun during the weekends (parked inside my office building during week days), but I usually notice that it drops 2 or 3 lines on the fuel gauge overnight. Could there be a leak somewhere? I don' smell any fuel and I hardly ever get to open VTec on my usually short route.

What do you think?

civdaddy

Parking on a unlevel surface seems to be almost certain why your finding the meter reading lower in the morning. It should go back up once you get the car level again.

Slowcrash_101

Things that will affect gas mileage, O2 sensor, Air filter, clogged injectors, bad PCV valve, clogged breather, underinflated tires, excessive toe, and a slipping clutch.

Clutch buzz is caused by the friction disk, if you replace the clutch, GO OEM ONLY, you can get a non OEM flywheel, but for the rest, go OEM if you want it to last more than 20k miles.

cdelena

When my car was stock ('00) and driven with a heavy foot in city traffic (lot of stops, etc.) it was not unusual for me to need gas in less than 200 mi so that is comparable mileage to yours. This car will get horrible mileage in some conditions (I used to get 8mpg on the track) and surprising mileage at times (I easily get 30mpg at a steady 55mph).

What you are seeing may have to do with driving conditions rather than mechanics.

jkelley

To add to the comments already made, the shorter your route, the worse your overall MPG will be.

CamsX

Thank you for your comments. Will still look into it, even if it means replacing or cleaning general maintenance items, so no harm in that I guess.

I'd figure the angle of the parking had to do with that, but the issue with the gauge is that what is "gone" overnight doesn't seem to return back to normal on even ground.

Got new tires and standard alignment 2 weeks ago. Will look into cleaning PCV when I get home. Where is this clogged breather you mentioned? New O2 sensor is out of budget right now. How would I know if it's bad?

For clutch was planning to go OEM plus ACT pressure plate. Is it worth the $200 difference?

Slowcrash_101

You can tell your O2 is bad if you have a strong stench of gasoline on your engine oil. The breather is the tube that goes from the valve cover to the intake, the pcv valve is in the middle, a new non oem one is $5 change them with your oil.

The thing about non oem that is usually garbage is the bearings. Non oem friction disks tend to have a horrible buzz to them, ACT pressure plate isn't worth the extra to me quite frankly, not if you're going to stay all motor.

A new primary O2 sensor is $90ish.

CamsX

Crap. I knew I was missing something important. The car has an S-AFC 1 installed. Had a tune when I got it, but I reset all settings to zero. Not sure if this could be messing everything up. By any chance anyone knows the default settings so that it is like it wasn't installed? I lack the skill to mess with the wiring and uninstall it. Doubt it was done using a proper harness.

Checked the metallic PCV (unscrewed it from the right side of the Cylinder head cover) and it looks as good as new. No dirt, and it rattles nice inside, like I read on some other thread. Failed to check inside the tube as I hadn't read your comment then. Thx.

Jdg784

Also if your car is anything like mine an 02 w/92.5k on it (apparently relatively common from what I gather) the cylinder 3/4 injectors have a tendency to develop a slight leak. This causes a low idle, mild smoking, and poor gas mileage. I swapped mine out (all 4 even though apparently only the rears cause issues_ for new OEM injectors a few days ago and it made a HUGE difference. All the smoke is gone, all hesitation is gone, as are all idle issues and I've logged roughly 26.5 mpg since then w/some serious vtec usage. Granted a considerable portion of my driving is highways (damned job!).

alSpeed2k

When I drive exclusively in stop and go traffic in the city my gas mileage is almost as bad as yours. I get better gas mileage during spirited canyon runs. Pure highway driving I can get 600+ kms. So if your 10minute commute actually takes 25-30minutes, I think the stop-and-go traffic is your culprit.