xiong28

I bought my 93 civic ex coupe auto trans last summer. When I first bought the car I consistently got about 30 mpg. I always reset my trip odometer every time I fill up and I always filled up all the way and drive until it's empty. My car usually took about 8.5-9 gallons to fill up all the way from E and I would go about 270 miles before i was back at E.

My mpg has gradually declined for a while now. Now I get about 220-230 miles per full tank. I just gassed up today and this last tank was my worst. I barely got 190 miles out of that tank.

I tried resetting the ecu by taking out the fuse, waited 15 mins, put it back in, and turn on the car let it idle for 15 mins. It seemed like it worked for a half a tank then the mpg went back down.

I haven't changed the air filter, plugs, fuel filter. I checked the air filter it could use a change but I don't think it should impact my mpg that much.

I'm thinking it is because my car is revving so high, on the highway at about 60 mph my car rpm is about 2.3k if not higher. Usually my car revs pass 4k if I am trying to merge into traffic on the highway. I took a video of my car from a stop and this was me driving conservatively, not granny style but no heavy foot either.

http://www.youtube.com/watch?v=0u6oBFXR2P0


Another problem I have is after driving I have a pinging sound. I'm not sure exactly where it's coming from. Sounds like it is coming from the cat but I'm not sure how that could be the cause. It's coming from the general area of where the cat is or more towards the driver side, if anyone has a clue what it could be.

http://www.youtube.com/watch?v=xpKuzElTiR0


Lastly my front driver wheel has been heating up a lot with a burning rubber type smell. It's on and off. This morning driving to work my car was pulling to the left if I let go of the steering wheel. Driving from work to school and from school home the alignment seemed to be fine again and no smell or hot tire when I got home. I changed the brakes not too long ago, I thought that could be the cause. The car used to shake a lot randomly and while braking before I did the brakes. The axle boots are ripped, I'm too lazy to change them, it's a pain to change them, and it's too cold. Can I get through the winter without replacing them?

Also the car sways back and forth on the highway when I have a heavy load. It's actually pretty scary and hard to control the car. It runs fine if it's just me by myself though. Lastly my car squeal when taking a corner, its the same sound of someone taking a corner too fast and the tires squealing on the pavement as the tires slide but for me it happens at slow speeds. I'm not sure what it could be, it seems the springs and shocks are fine but who knows. The tires have a lot of tread left and are wearing evenly. This car gives me headaches, I almost want to get a new car but my car still has so much life left with only 107,000+ miles. Plus I could use that money to do other things.

Former User

Any CEL codes?

Mileage - do a tune up (plugs, wires, cap, rotor, ignition timing)

Hot wheel - the caliper is seizing, likely due to bad or unlubricated slide pins.

Pinging - your engine is probably misfiring, leading to release of raw fuel into the exhaust system, where it is burning and making the exhaust system very hot. It's the expansion and contraction of the exhaust system that you may be hearing.

Swaying - check the suspension and struts.

TOO MUCH TORQUE

your gas mileage is probably because of your brakes dragging...

that will make your transmission shift higher rpms

xiong28

No check engine light. I haven't pulled any codes if I understand you corrrectly. I definitely need to do a tune up but can that effect my mpg that drastically?

How can I fix the brake issue? After I installed the brakes from time to time I did have some vibration but that went away after about a week.

Lastly how can I check for the misfiring?

Thanks for the replies.

StreetsideStig

A tune up can definitely improve your mileage. Old spark plugs, wires, cap, and rotor can lead to the aforementioned misfire, wasting fuel. You'll also use more fuel than needed if you have an old air filter. I would start with a tune up.

Edit: Actually, start with the brakes, because that's bad news. Then do the tune up.

xiong28

So where is a convient place I can order new pins from? Also what do I use for lubrication?

Former User

fungus mungus

You might also want to replace your O2 sensor. I had a bad one and my MPG went into the toilet.

fm

xiong28

Wouldn't a bad O2 sensor give me a check engine light?

fungus mungus

I know they do on an OBD2 car for the secondary o2 (the one after the cat), but I don't think the o2 will necessarily throw a CEL in an OBD1 car. I had a bad o2 that I recently replaced on my '94 GSR swap...no CEL. But checking it with datalogging on my Hondata, I confirmed that it was bad.

fm

StreetsideStig

I threw a code in my '90 Accord for the upstream sensor.

fungus mungus

So your mileage may vary...the lesson here is don't assume that the fact you have no code means your o2 sensor is good. Mine was definitely not working.

fm

xiong28

Can't I unplug the O2 sensor and see if that makes a difference in my mpg?

fungus mungus

You could try that. As others have indicated, you may or may not throw a code. But if the o2 sensor is bad, you won't see a change in your mileage. If it's good, it'll get even worse.

fm

Texas4door

When you do those brakes, have the rotors turned or replaced, cuz at over 100k miles, I can almost guarantee they'll be warped to some degree...might cause repetitive brake problems down the road as well as that bad vibration when you hit the brakes.