normal exhaust temperature
12-02-2020, 04:46 PM
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normal exhaust temperature
i just picked up a '93 4Runner for my son's first vehicle and am working on getting it back up and reliable. It sat for about 5 years so i started by dumping the fuel, cleaning the tank, replacing the filter and plugs. Also cleaned the injectors over the weekend. I finally got it running halfway decent but noticed a few things. the exhaust is really hot almost immediately after starting it. After about 5 minutes of idling both the catalytic converter and muffler are over 215 degrees.
The only code i am getting is 52, so maybe a knock sensor or wire? unless it is 5 and 2 (in that order, which i would think they would be in numerical order??) is the knock sensor causing the exhaust to be that hot? Is the catalytic converter blocked? any ideas?
i am new to the 3.0l but not toyota. I ran an FTOY for a few years in the rocks and have had a few tacomas and a newer 4runner. just trying to get this one back up is kicking my butt
The only code i am getting is 52, so maybe a knock sensor or wire? unless it is 5 and 2 (in that order, which i would think they would be in numerical order??) is the knock sensor causing the exhaust to be that hot? Is the catalytic converter blocked? any ideas?
i am new to the 3.0l but not toyota. I ran an FTOY for a few years in the rocks and have had a few tacomas and a newer 4runner. just trying to get this one back up is kicking my butt
Last edited by Spacecwboy; 12-02-2020 at 04:51 PM.
12-02-2020, 05:02 PM
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215 degrees is not hot. Converters often work at 1000 degrees F, and higher.
Even at idle, the exhaust manifold might read more than 215 degrees and the cat substantially higher than the exhaust manifold by several hundred degrees, if it is functional.
Code 52 will cause the engine to run rich, and a functional cat might well be expected to run extra hot.
Even at idle, the exhaust manifold might read more than 215 degrees and the cat substantially higher than the exhaust manifold by several hundred degrees, if it is functional.
Code 52 will cause the engine to run rich, and a functional cat might well be expected to run extra hot.
Last edited by millball; 12-02-2020 at 05:04 PM.
12-02-2020, 06:16 PM
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Code 52 is designed to make the engine run with ignition retarded. (I don't know if retarding the ignition would make it run rich, too.) Running retarded will definitely produce a very hot exhaust (like, red manifold, sometimes).
Code 52 is sometimes difficult to solve, but the most likely problem (and definitely the first step) is to replace the "pigtail" from the knock sensor in the valley to the connector just under the driver's-side edge of the plenum. You'll need to remove the lower intake manifold; since you cleaned the injectors, you already know the way.
Code 52 is sometimes difficult to solve, but the most likely problem (and definitely the first step) is to replace the "pigtail" from the knock sensor in the valley to the connector just under the driver's-side edge of the plenum. You'll need to remove the lower intake manifold; since you cleaned the injectors, you already know the way.
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