23 votes
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What's the purpose of having the cat right after the exhaust manifold

The main purpose of putting it right after the manifold is heat. The cat functions best when hot. Placing it as close as possible to the manifold helps the cat heat faster and stay hotter, which ...
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22 votes

Why does a catalytic converter have to connect to the engine electronically?

It is not a simple filtration system. It is, as the name implies, a catalyst system. In order to work properly, the catalyst must be maintained in the correct condition, which means, being fed the ...
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15 votes

How can I tell if I have bad cats?

Cats can stop functioning in a couple of ways: physical deformation due to high temperatures According to this article, the catalyst melts at temperatures above 2100 °F (1200 °C). In the event of a ...
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13 votes

How can I tell if I have bad cats?

Even before a cat plugs, you can test your cat using a laser thermometer. You are looking to compare the inlet and outlet temps on your cat. Do the following: Run the engine up to operating ...
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13 votes
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How does raw fuel damage the catalytic converter?

A catalyst is a chemical that contributes in a chemical reaction but remains unchanged after the whole reaction is complete. In a catalytic converter platinum is the catalyst that converts unburned ...
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  • 1,502
13 votes
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Is it a good idea to remove the catalytic converter?

tl dr: There would be no issues with the running of the vehicle. If the car in question is equipped with OBDII (or the international like), where the cat is being monitored by a second lambda sensor (...
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8 votes
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Can a car operate without a catalytic converter?

Most vehicles which are OBD-II compliant (newer vehicles are a little different) use just the O2 sensors located before the cat to adjust the air/fuel ratios. The in-cat or after-cat O2 sensors are ...
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7 votes
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How to install a California oxygen sensor into a federal catalytic converter assembly?

Looking at the description of the California O2 sensor for your car, the only thing different on it (besides the internals) is the electrical plug. The wrench which you tighten it down with is 7/8", ...
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7 votes
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Can a head gasket leak cause the cat to plug?

According to this website, the cat can surely be plugged by coolant entering the catalytic converter. Here are the reasons given on the website: Engine Tune-Up Required. A number of problems could ...
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7 votes
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Breaking in a new catlytic converter?

This website seems to answer all of the questions you have asked above. http://www.easterncatalytic.com/education/tech-tips/proper-break-in-can-prevent-future-problems/ The website discusses proper ...
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7 votes
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Locating the O2 sensors and the cat along the exhaust

Picture 1 is the downstream 02 sensor. Upstream is located on the exhaust manifold. Picture 1 contains both convertors. Picture 2 is the exhaust resonator.
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7 votes
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Can A Catalytic Converter Fail Due to Age?

It looks like usually, catalytic converters, if totally undamaged and treated correctly, shouldn't die with age. The article you referenced says, The truth is, on modern vehicles, the catalytic ...
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7 votes
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Should catalytic material be between upstream and downstream o2 sensor?

I suspect you diagnosed the situation correctly: that cat looks backwards. It’s a little hard to tell from the pictures but it looks like a straightforward manufacturing defect: the cylindrical ...
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6 votes
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Will Driving 100 Miles With a Misfire Damage My Car?

You should be fine. Though I would recommend unplugging the connector to fuel injector #7 to minimize the amount of unburnt fuel that makes its way to the catalytic converter.
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6 votes
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Can a universal catalytic converter be legally fitted to my Prius in California?

In short: no. To pass smog in California (and other CARB adopting states) the catalytic converter must be the one from the dealership or one that is in the Aftermarket Catalytic Converter Database. ...
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6 votes

What exactly is a catalytic converter and why does it need to operate within a certain range?

A catalytic converter incorporates a structure that is coated in precious metals. When catalytic converters first came out that structure was ceramic balls coated in the metals. This didn't work so ...
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6 votes
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What exactly is a catalytic converter and why does it need to operate within a certain range?

All of this comes from: http://auto.howstuffworks.com/catalytic-converter2.htm Ok, attacking each of these in order: What exactly is a catalytic converter? It is a device in the exhaust path of your ...
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  • 9,286
6 votes
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Coolant in the cat, can it be saved?

The concern is valid. Liquid coolant is not of particular concern when at ambient temperature. At higher temps the Phosphorous, used as a corrosion prevent agent in coolant, is a concern. It binds ...
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6 votes
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What socket fits the Catalytic-converter-to-Exhaust-manifold stud?

It's called a double D or shock absorber socket
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  • 1,326
5 votes

Removing catalytic converters on a 2000 v6 Mustang?

tl;dr: I can't find any evidence that removing the catalytic converters on this model will improve the car. It will definitely confuse the ECU (and obviously pollute more). I've looked hard for any ...
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5 votes

How can I tell if I have bad cats?

If an exhaust restriction is suspected a pressure gauge pre-catatlyst works just fine. My maximum cutoff pressure is 1.25 psi but most good systems will be well below that. The intake manifold vacuum ...
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  • 11.5k
5 votes

How to install a California oxygen sensor into a federal catalytic converter assembly?

Just to add to the other answer as I ran into this same issue, what kind of emissions do I have on my mitsubishi galant? I had this code: P0421 and I had to replace my O2 Sensor & the catalytic ...
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5 votes

What exactly is a catalytic converter and why does it need to operate within a certain range?

• Why does it need to operate within a certain chemical range? The gasoline engine catalyst feedgas (exhaust gasses) must remain in a very small window of fuel mixture because the chemical reactions ...
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5 votes
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2003 Toyota Corolla, 185k: erratic OBD codes, fuel smell, other symptoms

If you have rattling on acceleration and the fuel economy is depressed, it is very likely that the catalytic converter core has cracked and it is blocking the exhaust now. You can try to measure its ...
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5 votes

1998 Honda Civic - O2 sensor or catalyst failure?

Excellent graphs. The after catalyst sensor shows normal mixture readings. The PCM can and will operate the system lean or rich depending on operating conditions. The voltage will rarely be held at ...
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5 votes

I just removed ALL of the catalytic converters on my 5.7l Toyota Tundra. Now What?

If you're not worried about the check engine light (which will more than likely turn on since the 02 sensor will be receiving an excess amount of exhaust reaching it now) or environmental ...
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  • 1,948
5 votes

Can a permanently stoich or lean running engine ruin a catalytic converter?

A lean burn won't necessarily ruin your catalytic converter. What it may do long before that happens (depending on how lean you're running) is burn the exhaust valves, piston crowns and overheat your ...
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  • 2,645
5 votes

Incomplete Catalytic Converter Monitor on otherwise flawless old Tacoma

The monitors are usually run easily on this engine setup. The following pre-conditions must be met for running the monitor: Coolant temp above 176 deg F, Intake air temp above 14 deg F. No trouble ...
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5 votes
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Removing Broken Bolts

First of all, get some penetrating oil. I like PB Blaster but there are other brands. WD-40 is not a good choice. Liberally spray both sides and give it some time to penetrate. Overnight is a ...
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  • 8,829
4 votes
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How does push starting damage the catalytic converter?

unburnt fuel can damage the catalytic converter. By tow starting the car you could cause large amounts of unburnt fuel to be pushed through the engine and into the catalytic converter.
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