93 Honda Civic Mileage gone bad

Thanks for the link!

Mike

"Michael Pardee" wrote

the O2 sensor is

miles. I doubt many

all expect to

on or not). If

we suspect it, I

done with it.

party sensor

early models. I

and repost it.

I bought one for my 91 Civic from these folks about a year-and-a-half ago. Good service. No problems. I think their prices are competitive for more recent models, too.

From my reading on the net last year, people say to only buy OEM. Aftermarket are not as reliable.

For the original poster: Check that timing! I monkeyed with mine a bit a month ago, and I think it's why my mileage dropped a bit below 40 mpg on the last three tanks. So darn hard to see the timing marks lined up, especially with middle aged eyes. Or I didn't let the car warm up enough.

"Danny Beardsley" wrote

shipping mark.

After market, hmm. Let the group know how it goes. I'm afraid the aftermarket coils I've had did not last nearly as long as the original, OEM one.

Way to troubleshoot!

"Elle" wrote in news:jE7nf.2739$ snipped-for-privacy@newsread2.news.atl.earthlink.net:

Thanks much for the URL. I looked,and they did not list the 94 Integra GSR motor,just the RS,LS,SE models. I suspect the O2 sensor would be the same,though. Also,quite a big price difference between the OEM sensors and the universal.I guess you would have to "adapt" the wiring on the uni sensor.(no connector match)

In my experience, universals come with crimp splices to re-use the connector of the OEM.

Mike

| > the best thing to do is put in a new one and be done with it. Then why not buy new car & sell off old car ? I heard [i] japs export all their cars >5yr old, in whole or as components, to less developed countries with lower labour cost [ii] in Japan, new cars are cheap & repair costs high. Doesn't USA have the same situation ?

| will a 3rd party sensor suffice? only if it has the same capacitance value ( usually in µH i.e. micro Henry ) as the OEM part, so your ECU will not detect any difference

"TE Cheah" wrote in news:439de9e6 snipped-for-privacy@news.tm.net.my:

UH,microhenry is an INDUCTANCE measurement,capacitance is in microfarads,or picofarads.

the O2 sensor might be rated in millivolt output (per oxygen unit).

Right about the units, and the output is rather a moot point. The capacitance is immaterial, since it is used as a DC device. All use the same chemistry and are as very nearly identical, with the exception of the heater characteristics. Even at that the heaters are all 12V DC.

The essential characteristics (as I understand them):

*open circuit when cold, they are biased to 0.45 VDC to signal an inoperative condition *once they reach something like 450 degrees, they become conductive. If the exhaust has enough CO compared to the outside air, the device becomes a fuel cell and the output rises to approx 0.9 VDC. If the exhaust is lean, the output drops near zero (about 0.1 V is the figure usually given).

If the mixture is close to correct initially, the ECU drives the mixture back and forth across the transition point as rapidly as the feedback allows - thus the need for rapid response. Seven transitions per second is considered good, but I don't have a good handle on how slow is really considered bad. Maybe four... three?

Mike

Top Notch Shipping. Ordered itSunday night, recieved it Tuesday morning.

Anyway, it looks exactly like the coil that was in there already, it measures in spec (resistances of the coil), and has worked fine now that I've put it all back together.

Well.. I seem to have found the problem.

It was, as many have suspected, an old Oxygen Sensor. I was getting about 25ish MPG, and then I replaced the O2 sensor and now I have gone about 150 miles with the needle still above the 3/4 tank mark. I'll let you know the actual mileage when I finish the tank.

Thanks to everyone.

Especially thanks to Elle, who has been championing the O2 sensor issue for a while now. I'm coming to believe there are a lot of cars that are suffering degraded O2 sensor performance that haven't degraded enough to set the "check engine" light. My daughter's '93 Accord with 220K miles is a prime example. It doesn't make sense to assume a sensor that old is still working well. I hope to replace that one this spring - it's just too chilly now.

Mike

cars older than 1996 when OBD2 went into effect might *never* trigger the check engine light. i know my moms 1993 eagle summit never did.

im sure someone here with more knowledge would know whether itll even blink a code if/when checked.

"Michael Pardee" wrote

was getting

now I have gone

mark. I'll

sensor issue for

Yeah but I may have messed him over by casually mentioning my temptation "to pull off the ignition wire of the suspect cylinder (with the suspect fuel injector) and see if engine power sounds like it goes down." Shoulda been more complete; told him to follow a manual or Tegger's site on this point (which I believe mentions your experience on this, Mike); warned him about cranking the engine with any wire disconnected. It may very well have cost him the coil as well as time lost.

Gotta come clean, so maybe, with enough repetition in the archives someone else won't have this happen.

Sorry Danny.

you have convinced me to change mine as well (probably i'll check it first then change) as i am sporting a '93 civic si @ 195k with original sensor

btw is the accord having any oil trouble ? i am loosing about 1/2 qt between oil changes ?

was ther a final consensus on where to get good quality O2 sensors ?

robb

"Rob B" wrote Re oxygen sensors--

i'll check it first

sensor

about 1/2 qt

How much times is that in miles and months?

Doesn't sound too serious, but I'd still be checking for leakage around the valve cover; under the distributor; and into the spark plug tubes. How old's the valve cover gasket and the several other seals in the valve cover (spark plug tubes, oil filler cap, rubbery washers for the hold-down bolts)? Ever had the distributor O-ring seal (IIRC) replaced?

I did all of these not long ago, and my 173k mile, 1991 Civic's oil consumption seems way down, from about 1/2 quart between oil changes. Plus the exterior of the engine and the spark plug tubes are cleaner. :-)

sensors ?

In 2004 for my 1991 Civic, I used

for an OEM oxygen sensor ata significantly better price than the usual online OEM partssites. Good service. The sensor seems fine--still getting 40mpg most of the year on my 1.5L engine, manual tranny. So Ihave been recommending this company here when the subjectcomes up.

around 4500 mile oil changes, usually quite charcoal'd by then

takes about 10 months, it doesn't get the miles like it used to, recently went from 15k yr to about 5k yr

well i already had answered his in my head as (no leak) but i checked anyway and there was a freek'n leak coming somewhere from vicinty of valve cover and distributor base .... I can not believe i missed this on last oil change, it has a fine film oil all over that side if engine, wililnvestigate further

the distributor was replaced about 3 yrs ago so something has gone wrong

I'll check those as well

just looked there, i will compare with local foreign auto parts shop for sake of curiousity

thanks for info robb

"Rob B" wrote

loosing

then

used to, recently

For 10 months, that sounds like a leaky gasket somewhere, as I listed earlier.

My manual says to change the (non-synth) oil every 7500 miles or 6 months. Sometimes I hit the 6-month limit first. I'd say half a quart was what I was going through over that time--before I replaced certain gaskets.

I assume you're comfortable with the 10 months. If not, consider 6 months, which I think is what your manual also says.

and

gasket

plug

but i checked anyway

vicinty of valve cover

on last oil

engine, wililnvestigate

has gone wrong

My distributor housing was replaced about 2.75 years ago, and I think I'm seeing a little oil leakage down beneath the distributor. I cleaned up there (for the first time) a month ago, then checked again recently. I will probably replace the distributor O-ring within the next six months. That's not a hard job.