I have a 93 accord and it is getting like 16mpg before that it was getting 25mpg.
What would you guys suggest to change. I already have new plugs and wires, air filter, changed oil used k&nn oil filter. Should i change my fuel filter?
THANX

 

yeah those usually go along with the tune up. check ur old plugs and c how ur engine was running before hand.

 

Might test your oxygen sensor, they usually won't flip a CEL until they come close to failing altogether. Also make sure your EGR ports aren't clogged if you get really aggressive, but let me know if you do this cuz I been thinking about doing it.

Here's an awesome DIY w/pics
http://home.comcast.net/~em-engineering/T2T013.pdf

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I have a 97 Accord EX wagon, 4 speed automatic with 55k on the odometer. I bought it used 10 months ago with 48K. Have had poor gas mileage since I bought it and of course the guy I bought it from doesn't want to know anything about it. I've since had it tuned and the timing belt done using only OEM parts (Honda). Still getting the same poor gas mileage, usually 18-20 mpg, best was 23 mpg and that was an anomale. Took car to dealer and got the usual - "Can't find anything wrong". Too bad because I like the car and it runs very well. I'm looking for any advice or ideas to help remedy the problem. EPA estimates for my car are 23 city/30 highway. I'd be grateful for the 23 ANYTIME. Anyone out there with ideas/comments/suggestions? Please help or feel free to write me direct at: mdirollo@sbcglobal.net. Thanks to all !

 

Both of you should pay close attention to the suggestion Schmitey
made about your O2 sensor (in F22a1stick's case) and O2 sensor(s) (in Mdirollo's xase) (it's an OBD1, OBD2 thing)
The O2 sensor is the "Go-to" sensor the ECM uses to sample the final product coming out of the engine (it samples free oxygen). Depending on what it sees, it will adjust injector timing and duration to either add or subtract fuel from the intake charge to maintain optimum a/f ratio's and other perameters.
The sensor(s) can become lazy over time (for lack of a better term), and often will not set a code dispite being a little "off"
Adding fuel injector cleaner to a tank of fuel, and running a can of "SeaFoam" (a De-carboning agent) thru may help to clean them. If you see no improvement, anticipate replacement

P

 

You have an air leak somewhere. On that generation car, I ran on computer default for 6 months and got 23 MPG. If you have a vacuum guage, hook up to the intake plenum and see what you get at idle. Should be 21 - 23 in-Hg. Hook up to the vacuum inlet of the boost valve. If the vacuum climbs, replace it. Hook up to your EGR and pull a vacuum on it. If your engine doesn't stumble or noticably react, your ports are clogged. Now, many people on this site will argue over the pro's and cons of EGR and I will agree that it does not effect power if the ports are clogged, however, there has to be a difference in what the O2 sensor sees when, instead of 100% fresh air + fuel entering the combustion chamber, you have for illustration puposes 85% fresh air + 15% exhaust + fuel. This has to be seen by the O2 as a rich condition which it will remedy with a leaner mixture. On that age car, all of the orings and seals for all of the valves on the thottle body and the injectors are hard, flat, and brittle. They are cheap and easy to replace, especially if you go ahead and pull the intake off to replace the gaskets and clean those EGR ports. There is a bypass solinoid and vacuum diaphram beside the battery that also need to be checked to make sure they are not leaking vacuum. The cruise control has a vacuum system that should also hold vacuum. Checking for leaks is more than looking at the hoses.

 

make sure your tires are inflated properly as well. i have had everything mentioned plus the distubtor rebuild, new rotor and cap and still pretty much the same. i get about 220-230 before i hit 1/8 of a tank left. before i did any mods it was like 280.

 

good tips here with checking vaccuum and tire pressure!

As easy as it is I would really suggest just plugging the oxygen sensor(s) into a volt meter rather than messing with seafoam and the like. If they're bad they're bad, seafoam won't tell you either way.

 

O2 must be at 600 or 650 degrees to check. This car runs on default until it reaches temperature.

 

yeah hence you check the sensor and the heater element at the same time