Hey all, I have a 2000 Prelude SH, It's seems my gas economy is decreasing, I orginally got about 300 miles to the tank, after I put a K&N typhoon cold air intake it droped down to about 250, which I expected. Recently it's been getting about 200 miles to the tank and sometimes it doesn't even make it to that. Does that seem like a average gas economy for my car with a cold air intake? If not is there anything I can do to improve gas economy? Thanx in advance or any and all info.

 

Check your spark plugs?

 

wow i get like 350 per tank! i have a little more done to my can than you, although not much more. but my girlfriend also gets like 330 per tank and she has a cold air and ngk spark plugs. you should check your spark plugs, distributor cap and rotor, spark plug wires, air filter, and check your oil level too (as basic as it sounds). there's more, but i just can't think of it right now.

 

Ok, I ordered new NGK plugs and respective plug wires. If I'm supposed to be getting 300+ miles from the tank thats a pretty big gap since I'm only getting 200 -. I did a little research, would the oxygen sensor not working cause such a large gap ?

 

Change your fuel filter... any basic mechanic shop can do it... it should cost around 50-70 dollars... depending... Or if you want to do it yourself... It costs 12 bucks... For an ok one... haha. Good luck... Fuel efficiency is a big deal right now.

White

 

I have a 99 w/ a CAI & I get between 280-300 on average, but if I drive cautiously I can get 330ish.

 

yes an o2 sensor can make a difference. if its old or you burn oil it might be bad. i was thinking about replacing mine because lets say its 100 bucks and it gets me an extra 2 miles pergallon it saves me about 4 dollars a tank. so it will be paid off in no time the miles i drive.

 

Does anyone know how I access the O2 sensor and/or the fuel filter on a 2000 prelude SH? I believe both are pretty easy to install, I just dont knwo exactly where they are on the car.

 

i get about 280 - 300 depending on how much i boost

 

theres an o2 sensor on the cat. i think the other one is on the header.

 

I want your OEM air intake resonator & associated hardware

 

an intake should have little to no impact on gas mileage, if anything i'd think it would improve. first off stop racing around listening to your intake that'll save tons of gas, and if proper preventitive maintenance hasn't been done, do it.

 

the feul filter is located on the firewall kinda under the throttle body. it looks like a big black can with a few hoses coming off it. and the O2 sensor you want to replace is the one connected to the header.

 

Damn! That sucks bad. I get 350 miles to the tank if i go tearing around town everywhere. I can get over 400 on the highway. And I am so far from stock it is not even funny...

Pirate

 

I've been getting around a measly 270 but I need a tune up badly. Phil drive here and give my car a tune up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AzCivic1.6 &raquo;</TD></TR><TR><TD CLASS="quote">an intake should have little to no impact on gas mileage, if anything i'd think it would improve. </TD></TR></TABLE>
What he said.

 

i only get 300-340 per tank on 90% highway driving. i run A/C 100% of the time here in phoenix and its an automatic. I dont romp on it and I usually drive under 75mph. only mods are CAI and it has fresh plugs and cap and rotor.


neil

 

You might want to check out the 02 sensor to make sure it hasn't gone bad on you for some reason. If you fail emissions it would be a good sign of a bad 02 sensor, that could really kill your mpgs.

 

When rolling down a hill its better to leave the car in a high gear and just use your brakes while going down right? becuase your not adding any fuel, but if you leave the car in neutral it has to keep the car idling.... correct me if im wrong.

 

It is best to take it into neutral because it takes it down to idle rpms instead of 2500 or whatev you're spinning at going down the hill.

 

yeah but doesnt your car need fuel to keep it at idle, i was under the impression that you cut off all fuel while in gear while not pressing on the gas

 

I get about 350-400 a tank and I do not drive conservatively. I have way more than a CAI also.....

 

A clogged fuel filter would starve your engine, not make it burn more fuel. If your going to change the O2 sensors you need to remove them while their hot. They will break loose very easy when hot. I'm not of the opinion that the O2 sensor is the root problem. I think it is the consequence of the problem. It is much more likely that you have a vacuum leak somewhere that is causing your O2 sensor to think your mixture is lean.I agree that it is important too keep plugs, wires, and the cap and rotor fresh, but, if these items were bad enough to cause a 7 to 10 mile per gallon drop in fuel economy your car would be stumbling and bucking and missing. Vacuum leaks dilute the post combustion gasses and the O2 sensor compensates by increasing the pulse width to the injectors. If the leak is large enough it will also reduce the reference vacuum to the MAP, fuel pressure regulator, EGR, among others depending on your model. I guarantee you that replacing the O2 sensors will not give you back your gas mileage. Everyone on the civic or prelude site always want people to replace the distributor or the O2 sensor. It's their stock answer for 90% of the questions posted.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ideal &raquo;</TD></TR><TR><TD CLASS="quote">yeah but doesnt your car need fuel to keep it at idle, i was under the impression that you cut off all fuel while in gear while not pressing on the gas</TD></TR></TABLE>

No, if it cut off the fuel it wouldn't be able to keep running. It puts as much fuel in as it needs to keep it at the rpm you're at when you're going downhill, so coasting and lowering that rpm helps because you're going 50 mph or whatev but only using gas like you're idling.

 

it is true that it cuts gas when throttle is closed and going downhill. it might not cut it off 100%, but its alot less than idle. if you dont believe me, try this: drive down a street at 40mph. turn the ignition to acc while in gear. it will act the same as if you left it in gear with the ignition on.

neil