FYI,

I have an 92 Honda Ex with 280K miles that was showing a code 43 onthe check engine light. The car ran like new without any issues. Light would only come on after car was 100%wormed up. Replaced O2 sensor with aDenso and all is good again.Had the carsmog tested and passed again with flying colors.These cars are amazing durable.

 

Good to hear things are going well for the car

 

Never mind, code 43 came back after a few days. failed emissions test. Hi Co at Cruise test reading. CO registered 10.33 Limit is: 3.00 All other test passed. More testing to follow......

 

Update, I discovered that the new O2 sensor plug was saturated with oil inside leaking from the engine above and running down the wire. I wonder if this could cause an electrical disconnectionor short since my check engine light did not reappear within a week ofreplacing the sensor. Since re-cleaningthe sensor plug, filling it with dielectric grease and reattaching it in aposition where the oil will drip away from the plug, hopefully this works.Since the repair, no check engine light has reappeared.Will have the emissions rechecked againtoday and see.

 

Sure, oil leaking onto the plug can cause that.

You also want to prevent oil from leaking down onto the sensor. The O2 sensor actually measures oxygen DIFFERENCE from inside to outside. So oil on the outside of the sensor can throw off the measurement. So can exhaust leaking & blowing onto the outside of the sensor.

 

Thanks for your response Jim! Sure enough, it turn out to be the O2 sensor wire connection being full of oil causing the short. Just pass the emissions test with flying colors. I’m always amaze how well this car runs with 280,000 miles! Now just need to fix those pesky little oil leaks.