bad milage on honda accord.

[hectorladron]

hey guys, my gf has a 91 honda accord and lives in an area with pretty cold weather during the winter (-35 C). she is getting 350 kms on a full tank in the winter, and 400 kms in the summer. the milage has been droping during the past year. Its an automatic transmision, and the vehicle has 215 000 kms.
she really is getting fustrated, since she is a full time student and bought the car 2 years ago due to the good reputation that hondas have.
i am aware that the milage drops during the winter, but i still think its pretty low.
she will be putting an injector cleaner in the gas tank pretty soon, hoping that it will work.
the car just got tuned, so spark plugs are outta the question.....(i hope). so the only other things i can think of are a fuel system cleaner (to remove deposits, etc) and the oxygen sensor.
the vehicle drives normal, with no loss in power, and there are no warning lights coming on the dash.
do u guys have any simular expiriences, and can u recomend something?

thanx a million in advance.

 

[grant5127]

Any indications that the car is running rich??........When the MPG drops the first suspect is the water temp sensor. A bad water temp sensor will made the MPG go bad yet the check engine light will not come on. Water temp sensor is fairly easy and cheap to fix. The reason is that water temp sensor tells the computer that the car is COLD or not warmed up. And if the car is NOT warmed up, then it has to run RICH (like as if the choke was on).

The next two are O2 sensor and MAF sensor (but often these makes the check engine light to come on - but not always).......

 

[hectorladron]

Any indications that the car is running rich??........When the MPG drops the first suspect is the water temp sensor. A bad water temp sensor will made the MPG go bad yet the check engine light will not come on. Water temp sensor is fairly easy and cheap to fix. The reason is that water temp sensor tells the computer that the car is COLD or not warmed up. And if the car is NOT warmed up, then it has to run RICH (like as if the choke was on).

The next two are O2 sensor and MAF sensor (but often these makes the check engine light to come on - but not always).......

thank u very much for ur reply. i will pass it on to my gf.
ur response makes perfect sence and i hope it will work.

 

[hectorladron]

Any indications that the car is running rich??........When the MPG drops the first suspect is the water temp sensor. A bad water temp sensor will made the MPG go bad yet the check engine light will not come on. Water temp sensor is fairly easy and cheap to fix. The reason is that water temp sensor tells the computer that the car is COLD or not warmed up. And if the car is NOT warmed up, then it has to run RICH (like as if the choke was on).

The next two are O2 sensor and MAF sensor (but often these makes the check engine light to come on - but not always).......

is this the same sensor that turns the fan on and off?, or is it something totally different, also, u wouldnt happen to know where it is located, would u?

 

[Jimmy B]

A bit late,but along the same line as grant5127 on cold running motor,has she noticed it takes the car longer to warm up first thing?,longer for the heater to work,check for a faulty thermostat also,if it is stuck slightly or fully open,this could have a effect on milage,take it for a run on the highway and see what the temp guage does,if it does not have one run the heater a full blast and see if it puts out hot air and it will cool down as you run down the highway.I have gotten in the habit of blocking half the rads with cardboard during the winter on my trucks and notice quicker warm ups and better running temps similair to the warmer months.Never have had any overheating problems even on long highway runs.