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Hello to everybody in the forum. Looking forward to talking to you. I have a Honda Accord EX 1993 with excessive fuel consumption of 13.7 mpg compared to a standard of 22 mpg.
Two (2) years ago with 13.6 mpg I had a major tune-up with a local shop where the spark plugs, distributor cap and rotor, fuel filter and oxygen sensor were replaced. After that I got
about 15-16 mpg, a slight improvement. Now I am back to about 13.8 mpg. Also, the Engine Check icon in the dash is lighting when I am on the freeway. My mechanic did Diagnostic
Test and got an error code 43. He replaced the speed sensor on top of the transmission. I am bringing him back the car for further evaluation because it still lights up. I am thinking this must be related to the excessive fuel consumption. I would appreciate your comments.

Welcome to CleanMPG!

WOW! That's bad mpg!

What is your driving style. Explain your speed, starts, stops, length of commute, etc.

Was a compression test done by the mechanic?

Does the car idle smooth? How about on the road?

Jack the car up and check all 4 wheels to see if the roll free. Could be a brake (or 4:D) dragging.

There has to be something really wrong.

If you put your hand over the end of the exhaust with the car running, can you feel considerable amount of exhaust flow?

excerpt from this link (http://www.superhonda.com/forum/f49/error-code-43-fuel-supply-system-help-290567/):

the fuel supply code 43 is set and has 3 different diagnostic trees, two of which lead to replace o2 sensor.

at the dealer when a car comes in with a 43, it's an automatic start with heated o2 sensor. hook up the multimeter, run the engine at 3000 rpm, and watch the voltage. if it's switching between .1V - .9V too slowly, it's loosing it's touch. replace it. never use an o2 sensor not designed for your car, especially an OBDII lambda sensor in an OBDI engine.\


How many miles on the car? Automatic or straight drive? Has it ever had the timing checked? Or the timing belt replaced? What mods or aftermarket parts are on it?

As msirach suggested/asked: Have you had a compression test done on all cylinders. What is your style of driving?

What kind of gas are you using? Have you ever had it in the higher rpms (redline)? Has it ever been in an accident that might have damaged the exhaust system?

So many questions need to be answered to get a better idea of the problem. - Dale

I was going to suggest that the mixture might be rich due to a bad O2 sensor... but Dale beat me to it. :)

My mileage is about 142000 miles and am the original owner for 17 years. I am a conservative driver, no sudden starts or stops and light on the throttle pedal and drives at normal speeds. My car is automatic and I use Regular gasoline. I usually drive a radius of
about 10-15 miles from my place. No compression test yet on my car and the idle is smooth. Timing belt and other belts were replaced at 89000 miles and runs ok in the road.
All 4 wheels roll free. No aftermarket parts installed. Never reached the redline and no
accidents. There is pressure on the exhaust port when I feel it. The mechanic observed oil
in the oxygen sensor connector yesterday and cleaned it.

I would do the compression test next to see if you have worn rings. Does your car smoke either when you start it up, when accelerating or during normal driving? If it does what color is it?

If you have low compression in one or more cylinders it could be caused by:

1. Cracked head. 2. Blown piston 3. Cracked Block 4. Blown head gasket 5. Broken valve component - spring, cracked seat, bent valve, bad lifter.

Not saying this is what it is but a compression test will guide you/us to the next step.

Which oxygen sensor did he find oil on? - Dale

The oxygen sensor located on top of the exhaust pipe.

There are usually two. One before (closest to the engine) the catalytic converter and one after the cat (closer to the rear of the car). If your getting oil to either one from the exhaust manifold then this will show up in a compression test.

Does your car "use" oil? I mean do you have to put in a quart every month or two to keep it topped off? Or do you change it often and it's always a little or a lot low?

Notice any smoke coming out of the exhaust?

:cool: - Dale

I have never topped the oil anytime and the oil level is ok. At start-up and idle the exhaust
is clear and colorless. No unusual smoke observed.

good sign - Dale

Last week my mechanic replaced the heated oxygen sensor and it is covered with black soot which I believe indicates a rich fuel mixture. The Check Engine icon stopped lighting up thereafter. I also increased tire pressure from 32 psi to 35 psi after reading Better Mileage as per Dale. I also washed the engine to better determine the oil leak origin into the oxygen sensor connector. I will monitor gas consumption to see any improvement on my mileage. I will give updates also. Thanks for all your advice particularly Dale.

Widerland,
Thanks for the recognition. msirach and Right Lane Cruiser are both mechanically knowledgeable and I wouldn't hesitate to say that both could teach me a thing or two themselves. I have the "fortunate" experience of buying cars that always "need things" so my skills are out of necessity. I'll soon be your one stop Ford Aerostar specialist if you ever have the bad judgment or karma to actually own one.

If replacing the O2 sensor completely fixes your problem I would be a little surprised, with that much of a drop in fuel economy there may be some other issues still unresolved either from the O2 sensor or in addition to it. I would also pull the EGR valve off and have it cleaned (not replaced) with carb cleaner, replace the PCV valve (positive crankcase ventilation valve). These things are easy (EGR) and cheap (PCV). If you still have problems then do the compression test and give us the numbers for each cylinder. If there still is an existing problem then your CEL (check engine light) will most likely come on within 75 miles of driving it since it was last off.

If mileage is still low then keep us posted. :D - Dale

welcome to the forums mate and goodluck with your ride. :DGood bye spammer (http://temerc.com/Check_Spammers/index.php?name=&email=&ip=203.87.178.16&submit=check)