Horrible gas mileage on Honda

Hey guys, I'm here again, this forum always seems to have well balanced knowledge, so I'm coming to y'all. My daily driver is a 1996 Honda Accord. 4 cyl sedan. This car has a pretty big gas tank, 17 gal. But I only get 200 miles on a tank, I've don't some testing where I use the engine lightly for a while tank, and then with a new one I push the car hard for the majority of the tank. There's only a 10 mile difference on the whole tank, so don't worry, this doesn't have anything to do with my driving style. But getting 11 mpg on a honda seems very wrong. What do you guys think? Haha my friend with a Hummer gets better gas mileage than me.

 

How many miles/km on the clock?
Is it well serviced?
Blowing smoke/leaking?
Engine bay clean or oily?
Any vibrations or weird noises?

 

Is been well maintained, there's no blown baskets or anything. The only thing that's different about the car besides the mileage is the exhaust sound terrible. The engine Roma are normal. But it sound like an exhaust leak. Kinda like the exhaust isn't quite making it all the way through the muffler, and just escaping else wise.
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Do exhaust leaks affect gas mileage?

 

I'd assume so but not a huge amount, otherwise people with straight piped cars would be talking about it.

 

To be fair, fuel economy isnt the first thing that comes to mind for people with straight piped cars...

Though, I will say for most vehicles with emission systems on them, exhaust leaks might affect how much fuel the car uses, based on where the oxygen sensor is, since it might send bad info to the car's computer, for instance, if there's too much of an oxygen flow, it will tell the car to add more fuel to compensate for that to try to keep the air/fuel mix steady, and that might be where the poor fuel economy is coming from.

(though, don't hold a gun to my head if i'm wrong)​

 

Your Honda is 21 years old, of course it doesn't run as well as it used to.

 

for how old it is, it only has 230,000 miles, It may have to do with what @RiXeN_ has to say. I'll try to check for leak on the exhaust, I'll let y'all now later.

 

The exhaust leak will suck mileage away but I don't think by that much.
Things you need to check for:

• Check engine light - is it on? If it is, chances are because it's so old, the car goes into gimp mode shutting off efficiency sensors. Find out what it is and troubleshoot and replace it. Scanners go for as little as $20 on ebay.
• Coolant level/color - CHECK IT COLD, DO NOT CHECK IT HOT. If it's yellow or almost rust color, you could have a broken head gasket and this means your engine is burning coolant. Keep in mind, if it's yellow, it could just be old. Another way to check is a high temperature on the gauge and extra steamy exhaust. A way to check is by pulling out your spark plugs and seeing if they look crusted in a white substance or they look rusted.
• Oil level, color, and consistency. If it's low, your piston rings or valve seals could be bad and letting oil into the engine and burning it. This would make a blue smoke and smell bad. A good way to see if you're burning oil is by pulling out your spark plugs and seeing how they look. If they look tinted blue, you're burning oil.
• Catalytic converter dead? This is hard to check for without pulling it apart. By dead I mean clogged so this kills airflow and hurts efficiency.
• Timing belt (or chain? I think Hondas used belts) Could be well overdue for maintenance.
• Ignition system: Could also be well overdue for maintenance (distributor, cap, and rotor, and wires, spark plugs too.)

How is the engine performance? Is it fairly responsive or does it feel sluggish?

I hope this helps.

 

Oxygen sensor can also be faulty, that can cause ECU to enrich mixture by maximum value possible, if it is 20% or 5% depends from ecu then.

I had to fix one of such econobox ones, spark plugs were all black as it was running so rich, for some reason oxygen sensor read lean, but with ECU enriching mixture it read enough good for not causing a fault. We swapped new sensor in and it started working fine.

Once there was then car that had failed emission checks, guy says he checked air filter, we trusted his word and could not find what is wrong, then as we pushed guy a bit he opens air filter box and shows that filter is clean, it turned out to be clean side of filter facing up that he had checked and there was all kind of growth underside of the filter, replacing that made car run much better.

Sometimes it is little things, but can be fuel tank leaking too, gasoline disappears so fast that there is no puddle, sometimes bit hard to find out, especially outdoors.

 

"Only" Are you joking?

 

What do you mean, that is just decent run in and you can start using it bit harder now?

 

Keep up the maintenance and a car with that many miles will run like new

 

I'm not joking, hondas in my area easily get 320,000+ Miles

@iheartmods the car is very responsive, nothing is wrong with it or seems off besides the gas mileage.. no check engine light.

 

My friend just picked up 94 Integra gsr. 240k miles on the original motor. He's averaging mpg in the mid 30s. Something is wrong here for sure. Clogged filter? Clogged cat converter? Check engine lights? I have a decent exhaust leak and I get mid 30s too.

 

I had a similar problem with my car, turned out the cable of my O2 sensor was torn. Probably worth a look.

 

200,000 is a lot of miles...
It took my mom 11 years to get 100,000 miles on her daily, a 2005 ford escape. Now she has a Grand Cherokee.

 

O2 sensor sounds to be the culprit. Common to go, easy to replace, cheap. Really about the only thing I ever replaced other then normal maintanance on my '93 accord which had just over 400k kms on it.

Also could be the air filter, even on my 2013 Fit I noticed back gas mileage, bit of shudder on start, and much more carbon then usual coming from the exhaust pipe. My air filter was nearly suffocating my engine it was so bad, even only being a month old thanks to the local forest fires.

And of course tire pressure, and oil.

 

Does the engine light actually come on the second click of the key before starting it? Someone took the bulb out of my first car, not that it affected it in any way, probably a bad lambda sensor on the cat.

My first port of call would be to service it, spark plugs, air filter, oil & filter won't make any difference just make your engine last longer.

It has 230,000 miles, and 21 years old, I'd be rallying it around not caring about MPG. If you want high MPG and good fuel economy get a little diesel. Here in Britain the 1.4 TDCI's are slow as hell, but get very good MPG, like 400 miles to a tank if not more.

 

can screw with o2 sensor readings and hence cause engine to start rich or lean burning, if it opts for rich then that would be negative impact on fuel economy.

And when most cars average 10000miles per year, i wouldnt call 230000 "only". Seems normal. Combine with most cars only having a design lifespan of 150000. Its had a good run.

 

A clogged fuel filter, injector, fuel line or stale gas can cause horrible gas mileage.
(My mothers SUV gained 3 MPG by having its injectors cleaned and fuel filter replaced.)