Four Oxygen Sensors?!

PKRWUD · 09-18-2001, 09:20 PM

MYTH?!?!?

Frank, I just lost all respect.

Have you heard about all the newer, cheap japanese engines that are for sale? In Japan, the standards for maintaining a vehicles registration are so extensive that it's not practical to keep a vehicle for more than 5 years. Most are less than 3. They then dismantle them and sell the parts overseas. There are dozens of places that sell nothing but imported japanese engines with low mileage, and they're very inexpensive. As it turns out, that's because most of them are trashed. The running logic there seems to be "why change the oil if I'm going to junk it @ 75k miles". I have removed oil pans from these engines, with less than 75k miles, and only 3 or 4 years old, and there was a "shell" formed by the crusty, sludged up oil. It had to be pryed away just to see the crank. The bearings in these engines looked like they had been used for 300k miles. Everything was extremely worn and/or damaged, and gave the impression of being from a 300k mile work truck.

Anyway, it's not a myth.

As far as not changing the O2 sensors until the check engine light comes on, that's about the worst advice I've seen today. That's just like not checking the oil until the engine light comes on. When the O2 sensors return signal isn't what it should be, the ECM will let you know, but it's not black or white, pass or fail, good or bad. They deteriorate as they age, and while they deliver a signal to the ECM that the ECM determines to be acceptable, it's not accurate. Tha average recommended O2 sensor life span, for a stock drivetrain, is 30k miles. Start screwing with the ECM by installing a lower temp t-stat, or setting the TPS voltage at .999, and you can cut that expectancy in half. It could still take 100k miles or more before the ECM decides it's bad, but by then you've paid the price with bad fuel mileage and accelerated engine wear. Older vehicles have an O2 sensor replacement warning lamp that is tied into the odometer, because it was too difficult for the ECM to determine accurately the condition of the O2 sensors and when they would need to be replaced. If yours have more than 60k miles on them, I would go ahead and replace them.

Take care
~Chris

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09-18-2001, 09:20 PM	#10
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	MYTH?!?!? Frank, I just lost all respect. Have you heard about all the newer, cheap japanese engines that are for sale? In Japan, the standards for maintaining a vehicles registration are so extensive that it's not practical to keep a vehicle for more than 5 years. Most are less than 3. They then dismantle them and sell the parts overseas. There are dozens of places that sell nothing but imported japanese engines with low mileage, and they're very inexpensive. As it turns out, that's because most of them are trashed. The running logic there seems to be "why change the oil if I'm going to junk it @ 75k miles". I have removed oil pans from these engines, with less than 75k miles, and only 3 or 4 years old, and there was a "shell" formed by the crusty, sludged up oil. It had to be pryed away just to see the crank. The bearings in these engines looked like they had been used for 300k miles. Everything was extremely worn and/or damaged, and gave the impression of being from a 300k mile work truck. Anyway, it's not a myth. As far as not changing the O2 sensors until the check engine light comes on, that's about the worst advice I've seen today. That's just like not checking the oil until the engine light comes on. When the O2 sensors return signal isn't what it should be, the ECM will let you know, but it's not black or white, pass or fail, good or bad. They deteriorate as they age, and while they deliver a signal to the ECM that the ECM determines to be acceptable, it's not accurate. Tha average recommended O2 sensor life span, for a stock drivetrain, is 30k miles. Start screwing with the ECM by installing a lower temp t-stat, or setting the TPS voltage at .999, and you can cut that expectancy in half. It could still take 100k miles or more before the ECM decides it's bad, but by then you've paid the price with bad fuel mileage and accelerated engine wear. Older vehicles have an O2 sensor replacement warning lamp that is tied into the odometer, because it was too difficult for the ECM to determine accurately the condition of the O2 sensors and when they would need to be replaced. If yours have more than 60k miles on them, I would go ahead and replace them. Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!