Install walker 15538 catalytic converter '91 nissan

Common Problems That Trigger the P0422 Code

Defective Catalytic Converter
Engine misfires have damaged the Catalytic Converter
Internal engine damage resulting in high oil consumption and/or a leaking Head Gasket has damaged the Catalytic Converter
Common Misdiagnoses

Oxygen Sensor(s) are replaced when the real problem is a damaged Catalyst
Catalyst is replaced when the real problem is internal engine damage, which is producing elevated emissions levels
Catalyst is replaced when a misfiring engine is the real problem

Catalytic Converter? - Nissan Titan Forum

www.titantalk.com > ... > Titan Performance Modifications
May 31, 2010 - 15 posts - ‎10 authors 2004-2006 4wd = 4 cats, you can remove (or gut) the two rear cats with no issues...just..... I have a 06 2wd I am about to do the exhaust. Hello Titan Owners! NEED HELP . Catalytic Converters ...
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Friend, your car has only one (1) catalytic converter. It may have one or two mufflers. Tenneco makes the Walker brand of mufflers and catalytic converters and have many for most cars. Check their online catalog to see it a system is available for your car. I would recommend you replace the one or two Oxygen sensors at the same time... poor gas mileage is often the result of failed Oxygen sensors. Most cars have two, some have only one. One may screw into the exhaust manifold (header pipe) and another after the catalytic converter. Good luck ;)

Replacing a catalytic converter ranges from easy to moderate for most DIY mechanics. It is best to take off the entire exhaust system (not the exhaust manifold or headers) for a through inspection when doing this job as a bad catalytic converter is a sign that other parts of the exhaust system may be requiring replacement as well including the muffler(s) and tail pipe(s). Tenneco's Walker Muffler site has detailed schematics for both domestic and foreign cars. TRW Aftermarket may carry them too. (If you own a very expensive car; you plan on keeping for a long time , see about a stainless steel exhaust system... Borla, Remus, Supersprint, Bosal, and ANSA make many for foreign cars.) The other thing(s) to check and remove before taking the exhaust pipes off are the 1 or 2 Oxygen sensors... they will affect your gas mileage significantly. Unplug the wires to them and unscrew the front one and look at it. If it's filthy fouled replace it and the lower (if there are 2) one too... the information from both of them influences the car's ECM/ECU computer to adjust the air/fuel mixture.. (NGK, Beru, and Bosch make oxygen sensors for most cars.) Ensure you buy new exhaust pipe hangers and mounting bolts, if your hangers don't include them. Use Penetrating oil on a COLD exhaust system to help free up the bolts that join the lower part of the exhaust manifold to the first part of the exhaust system. Letting it sit overnight seems to work best. You may need a new gasket there so prepare and buy a new one to replace it. (When replacing, tight is good, too tight is bad as you may break off the stud or bolt.) IMPORTANT!!! Old catalytic converters need to be disposed of as hazardous waste as they contain several gridded wafers of electroplated platinum base metal. (Contact the new catalytic converter seller to see if they will take your old one or contact your city or county disposal office to see how to properly dispose of a used one.) Exhaust pipes typically fail where there are bends as the metal is stretched and thinner there... look for holes and rust. Typically, a ratchet set, rubber mallet and hacksaw may be required to cut a catalytic converter out and then crush the round inner sleeve remaining inside the exhaust pipes ends with a thin flat chisel, pulling it out of the "good" exhaust pipes using locking pliers (a.k.a. Vise Grips tm). (Alternatively, a rubber mallet may be used to strike the catalytic converter to break it loose from the exhaust pipe ends... DO NOT DO THIS if the catalytic converter is in the disintegration stage. Do Not use the mallet on the exhaust pipes as they will bend!) Use crocus cloth or sand paper to smooth the inside of the exhaust pipe connections and ensure by trial off the car that the new catalytic converter goes in the pipe ends easily before mounting the separate pieces on the car... terrible to learn it won't go in, due to carbon soot or rust when you're on your back underneath!

When replacing your converters you can eleminate the second converter, shops in different states have different rules that may prevent them from losing the 2nd converter but you as an end user can but an aftermarket converter that will fit your car and install it yourself. This will require a sawzall or a good hacksaw to remove the old units so as to leave enough pipe coming down from the exhaust manifolds for the new converter to clamp on. Once the new converters are installed any muffler shop can hook up the rest of your system.

Take it back to who ever is guessing what the issue is and tell them to fix the intake gasket. IT was not installed correctly or torqued right. Depending on the mileage you may get a free catalytic converter. They are rated for 10 years. Contact a dealer about it. But if you had a blown head gasket and coolant got into the exhaust, the cat should be replaced. Silicon additives in coolant ruin catalytic converters

P0420 NISSAN - Catalytic Converter Efficiency Below Threshold Bank 1

The most common cause for the OBDII code P0420 on Nissan vehicles is the three way catalytic converter Bank 1 has reached the end of its useful life.. Since this is a very expensive part you need the code fully diagnosed as some other things like exhaust leaks or poor engine tune can cause it as well

Front Pipe REMOVAL & INSTALLATION Pipe Without Catalytic Converter

1. Before removing any component of the exhaust system, always squirt a liquid rust dissolving agent onto the fasteners for ease of removal..
2. Raise and support the front of the vehicle on jackstands.
3. Remove the exhaust pipe-to-manifold nuts.
4. Support the catalytic converter, then disconnect the pipe from the converter. Remove the pipe.
5. Remove the exhaust gaskets. To install:
   
6. Be sure to use all new gaskets when required. Assemble the system, check the clearance and tighten the bolts to about 15-30 ft. lbs. (20-41 Nm). Fig. 1: Front exhaust pipe connection common on vehicles with the catalytic converter not included
   
   
7. All clamps should be tightened to about 18-25 ft. lbs. (24-34 Nm). Do overtighten the clamps. If pipes become dented they can leak.

Pipe With Catalytic Converter

1. Before removing any component of the exhaust system, always squirt a liquid rust dissolving agent onto the fasteners for ease of removal.
2. Raise and support the vehicle.
3. On some vehicles you will need to remove the brace from the transaxle.
4. Remove the exhaust pipe nuts from the manifold.
5. Support the catalytic converter pipe bolts from the rear of the converter.
6. Lower the catalytic converter/front pipe assembly from the vehicle. To install:
   
7. Be sure to use all new gaskets when required.
8. Attach the new catalytic converter/front pipe assembly to the vehicle. Tighten the pipe to manifold nuts to 20-40 ft. lbs. (27-55 Nm).
9. Attach the bolts at the rear of the catalytic converter/front pipe. Tighten them to 30-35 ft. lbs. (41-47 Nm).
10. Connect the brace at the transaxle if removed.
11. Lower the vehicle.

I think you need to verify that the catalytic converter on the drivers side isnt plugged. If there is an exhaust leak, it could cause problems also. So is the intake gasket leaking or not?

Catalytic Converter Removal & Installation 2.2L Engine To Remove:
Catalytic converter 2.2L engine

1. Raise and safely support the vehicle.
2. Disconnect the heated oxygen sensor (HO2S) electrical connector.
3. Remove the exhaust manifold pipe flange mounting nuts from the catalytic converter.
4. Remove the catalytic converter flange mounting nuts from the muffler.
5. Remove the catalytic converter from the muffler.
6. Remove the catalytic converter from the rear hanger bracket insulator.
7. Remove the catalytic converter.
8. Remove the (HO2S) from the catalytic converter.

To Install:

1. Install the (HO2S) to the catalytic converter.
2. Install a new gasket and the catalytic converter to the muffler.
3. Install catalytic converter to the catalytic converter hanger.
4. Install the catalytic converter flange mounting nuts to the muffler flange.
   • Tighten to 26 ft lbs (35 Nm).
5. Install the catalytic converter flange mounting nuts to the exhaust manifold pipe flange.
   • Tighten to 26 ft lbs (35 Nm).
6. Connect the heated oxygen sensor (HO2S) electrical connector.
7. Lower the vehicle.

------ Catalytic Converter Removal & Installation 4.3L Engine To Remove:

1. Raise and safely support the vehicle.
2. Raise and support the transmission.
3. Remove the transmission support
4. Disconnect the left and right pre-converter heated oxygen sensor (HO2S) electrical connector.
5. Disconnect the post-converter (HO2S) connector. Muffler flange and gasket
   
   
6. Remove the catalytic converter flange mounting nuts from the muffler.
7. Remove the catalytic converter from the muffler.
8. Remove the exhaust manifold flange mounting nuts from the catalytic converter. Catalytic converter 4.3L engine
   
   
9. Remove the catalytic converter from the support bracket insulator.
10. Remove the catalytic converter and gaskets.
11. Remove the heated oxygen sensor.

To Install:

1. Install the heated oxygen sensors as needed.
2. Install a new gasket and the Install the catalytic converter to the support bracket insulator.
3. Install the catalytic converter to the exhaust manifold flange. Install the mounting nuts.
   • Tighten to 39 ft lbs (53 Nm).
4. Using a new flange gasket, install the catalytic converter to the muffler. Install the mounting nuts.
   • Tighten to 30 ft lbs (40 Nm).
5. Connect the left and right pre-converter heated oxygen sensor (HO2S) electrical connectors.
6. Connect the post-converter (HO2S) electrical connector.
7. Install the transmission support.
8. Lower the transmission.
9. Lower the vehicle.

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It looks like you can cut them and replace them with new bolts and nuts.