Check Engine Light

I would appreciate some feedback on the following issue I have with my Honda Accord. First, some info. on my car:
It's a 1994 Honda Accord EX 4-door Sedan with the VTEC engine. I am the
original owner and have used it primarily as a 2nd car and mainly for city driving and relatively short trips. Therefore, It only has 76,000 miles on it. I have taken good care of this car, for the most part, and it hasn't needed much more than regular maintenance. I have changed the oil on average about every 4,000 to 5,000 miles. It has not yet had the original timing belt replaced. The Honda specialist who services my car says it's probably OK for now, based on the limited mileage I have put on the car.
About 9 months ago, the yellow "Check Engine" Light started coming on intermittently. Usually, it comes on either immediately or shortly after starting my Honda when the engine is cold. If I shut the engine off and re-start it, the "Check Engine" light will go away until my next cold engine start. However, if I don't shut down and re-start the engine, the light will stay on as long as I drive the vehicle (until I shut off the engine). Sometimes the light comes on well after I have started up the cold engine. But again, It will go away (temporarily) if I shut down and re-start the engine.
During this time, I have had a comprehensive tune-up (including valve adjustment) done on the car and replaced the muffler assembly. Neither one of these things solved or even reduced the problem.
My owner's manual says that if the light goes off after shutting off and re-starting the engine, that it is not as serious as the light staying on continuously even after re-starting the engine.
From reading this newsgroup, it seems like many different things can cause the "Check Engine" light to come on, some serious and some not so serious. Anyone have any idea what could be causing this problem and how I could diagnose/fix it? Could the warning light just be a false positive due to the age of the vehicle and the sensor not working properly?
Thanks for your help!
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Vikings Fan wrote:

(Oxygen Sensor) will be the cause.
Phil
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Thanks Phil, but is the problem likely as simple as that? I hope so . . . I'll start there.

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Vikings Fan wrote:

================================= Your timing belt is OVERDUE, based on TIME. Phil may be right about the sensor . . Having the code read is the logical place to start. You don't need a Honda dealer to do either.
Read this part of Tegger's FAQ regarding the belt http://www.tegger.com/hondafaq/faq.html#interference
'Curly'
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<snip>

A 1994 Civic is not OBD-II. AutoZone's free code reading service will be useless determining the error stored in the ECU, unless they do OBD-1 as well (do they?). In any case, AutoZone in California will not do free code reads for you, if you happen to live there.
Check here: http://www.tegger.com/hondafaq/faq.html#retrieve Start from Page 13 of the PDF. You need to short the Service Connector with a paper clip and read the flashes of the Check Engine Light.
There may be both long and short blinks, and the sequence will be delimited by a long pause. A long blink is 10, and a short is 1, so the sequence long-long-short is code 21.There may be more than one code stored, so watch carefully!
If you do not have a free PDF reader, click here: www.adobe.com
You need to get the error code and post back here. If the CEL keeps coming on, there is a persistent problem that needs attention.
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TeGGeR

The Unofficial Honda/Acura FAQ
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Guess I should give the URL to the actual PDF, no? http://www.iequus.com/assets/manuals/3173_ICCR_E_14JAN03.pdf
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TeGGeR

The Unofficial Honda/Acura FAQ
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Download Foxit PDF reader. Much less CPU demanding than Adobe's 11MB reader.
Foxit reader home http://www.foxitsoftware.com/pdf/rd_intro.php
Download http://www.foxitsoftware.com/pdf/pdfrd.zip 1.3 MB
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Vikings Fan wrote:

basically, the temp sensor in the head doesn't get properly immersed, so it registers low - thus causing the engine to over-inject gas. this causes the exhaust to remain too rich and the oxygen sensor registers an error.
first, get the code for the error to confirm what the ecu thinks the problem is.
second, check the coolant in the radiator [when cold, remove the cap and look inside] - do /not/ assume that because the expansion bottle is full, that the radiator is full.
third. find yourself a better "honda specialist". valve adjustment and muffler replacement are just so low down the list of probable cause, you can pretty much disregard them.
once you've done that, get on with the proper diagnosis. use whatever the ecu says is code to start, then work from there. respond back to group with the code[s] and any further diagnosis you've had.
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