Question about 1987 Honda Accord

1 Answer

Nocs too high on 2nd ga emissions test

Already replaced catalytic converter, oxygen sensor, tune-up. Nocs too high on heavy load test by 600 points. Performed tests suggested in manual on Air Intake system. Solenoids don't seem to have vaccum but don't know if shouold replace the two solenoids or it iselectricial. Volt test lowon solenoid. Rewtired honda man confined to wheelchair with MS unable to perform all tests in manual. Any suggestions. Not running hot nor is trans slipping so don't think it is EGR.

Posted by on

Ad

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that gotĀ 5 achievements.

    Governor:

    An expert whose answer gotĀ voted for 20 times.

    Scholar:

    An expert who has written 20 answers of more than 400 characters.

  • Expert
  • 123 Answers

Getting your hands on an EGT sensor would help, along with hooking up an A/F gauge, A faulty coolant temp sensor could cause this issue without a doubt. Even using a infrared temp gauge would help, hitting each cylinder checking outside temp could indicate a lean or rich cylinder condtion.

Posted on Sep 21, 2008

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

2 Answers

Location of code p1137 on 01 alero


catalytic converter .
In order to control emissions, a catalytic converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide.
The powertrain control module (PCM) has the capability to monitor this process by using a rear-heated oxygen sensor (HO2S 2). The HO2S 2 , located in the exhaust stream past the catalytic converter, produces an output signal which indicates the storage capacity of the catalyst. This in turn indicates the catalysts ability to convert the exhaust emissions effectively. If the catalyst is functioning properly, the HO2S 2 signal will be far less active than the signal produced by the front oxygen sensor (O2S 1).

Feb 12, 2017 | 2001 Oldsmobile Alero

1 Answer

Code p0420 acura m'dx


1996-newer (OBD-II) vehicles use oxygen sensors and a catalytic converter to reduce emissions. There is one O2 (oxygen) sensor in front of the catalytic converter (called upstream), and one behind it (downstream). When the engine is warmed up and running normally the upstream oxygen sensor reading fluctuates and the downstream one is fairly steady. In the case where both readings are fairly steady, a P0420 check engine light code is set.
Possible Causes: Oxygen (O2) sensor not working correctly
Damaged or leaking exhuast (pipe, manifold, catalytic converter)
Damaged catalytic converter
Diagnostic Help:
To diagnose a P0420 trouble code we begin by checking for exhaust leaks under the vehicle. Then use an oscilliscope to check the waveforms of both upstream and downstream O2 sensors. The front reading should vary, the rear should be steady. Replace as necessary. Check the rear Heated O2 Sensor. Check the catalytic converter, replace if necessary. If necessary, check for wiring and component concerns. See our article "Automotive Circuit Testing 101", if you need more assistance with this. Remember to refer to an model-specific repair manual for proper instruction.

Jan 20, 2014 | 2005 Acura MDX

2 Answers

P0420


Hi there:DTC P0420 - Catalyst System Efficiency Below Threshold (Bank 1)



The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar.



This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.


A code P0420 may mean that one or more of the following has happened:



Leaded fuel was used where unleaded was called for
A damaged or failed oxygen sensor (HO2S)
Downstream oxygen sensor (HO2S) wiring damaged or connected improperly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe
******** spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Leaking fuel injector or high fuel pressure
Cylinder misfire
Oil contamination


Possible Solutions: some suggested steps for troubleshooting a P0420 error code include:


Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
Inspect the downstream heated oxygen sensor (HO2S), replace if necessary
Replace the catalytic converter
Overall probably the biggest mistake vehicles owners make when they have a P0420 code is to simply replace an oxygen sensor (H02S). It is important to do proper diagnosis so you're not wasting money replacing parts unnecessarily.


We strongly recommend that if you need to replace the catalytic converter that you replace it with an OEM unit. Second choice would be a high-quality replacement part. There are many stories in our forums where folks replaced the cat with a cheaper aftermarket one only to have the code return shortly thereafter.


One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.


Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Aug 22, 2012 | Chevrolet Cars & Trucks

1 Answer

Check engine with code p0420


Generally, this code is from a failed converter. Most exhaust or diagnostic shops can perform a converter back pressure test to confirm if the converter is failing.


DTC P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar.


This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Some suggested steps for troubleshooting a P0420 error code include:

  • Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
  • Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
  • Inspect the downstream heated oxygen sensor (HO2S), replace if necessary
  • Replace the catalytic converter

Overall probably the biggest mistake vehicles owners make when they have a P0420 code is to simply replace an oxygen sensor (H02S). It is important to do proper diagnosis so you're not wasting money replacing parts unnecessarily.

We strongly recommend that if you need to replace the catalytic converter that you replace it with an OEM unit. Second choice would be a high-quality replacement part. There are many stories in our forums where folks replaced the cat with a cheaper aftermarket one only to have the code return shortly thereafter.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.


Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Jun 22, 2012 | 2002 Chevrolet Impala

3 Answers

2001 Nissan Sentra. Car starts with no power, but after a few restarts, gain power again. Code is PO420.


Hi, P0420 code means a catalytic converter fault.
The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
  • Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
  • Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
  • Inspect the downstream heated oxygen sensor (HO2), replace if necessary
  • Replace the catalytic converter

Jul 22, 2011 | Nissan Sentra Cars & Trucks

2 Answers

P0422 general evap failure i tested gas cap and it failed replaced gas cap and repaired a vac hose to the purge soilniod light comes back on within 10 min of clearing it


P0422 Buick - Catalyst below threshold.

Catalytic converter is clogged or out of medium.

Replace it.


ACTUAL DIAGNOSTIC:

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

Symptoms

* Check Engine Light will illuminate
* In many cases, no abnormal symptoms may be noticed

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 Sensors 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



Thanks for using FixYa - a 4 THUMBS rating is appreciated for answering your FREE question.

Sep 28, 2010 | 1999 Buick Regal

1 Answer

My check engine light came on with P0422 and P0455 codes. Any suggestions as to the cause.


P0422 - Catalyst below threshold.

Catalytic converter is clogged or out of medium.

Replace it.


ACTUAL DIAGNOSTIC:

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

Symptoms

* Check Engine Light will illuminate
* In many cases, no abnormal symptoms may be noticed

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 Sensors 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



Thanks for using FixYa - a 4 THUMBS rating is appreciated for answering your FREE question.*&#$%

Aug 04, 2010 | 2008 Saturn VUE

1 Answer

My 1991 4runner failed emissions test with high CO and HC levels.


Not sure, but did you replace the oxygen sensors. Is your catalytic converter still good?

Aug 21, 2009 | 1991 Toyota 4Runner

1 Answer

1999 beetle P0422 which O2 is bad the o2 before the cat or after


P0422 - Catalyst below threshold.

Catalytic converter is clogged or out of medium.

Replace it.


ACTUAL DIAGNOSTIC:

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

Symptoms

* Check Engine Light will illuminate
* In many cases, no abnormal symptoms may be noticed

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 Sensors 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



Thanks for using FixYa - a 4 THUMBS rating is appreciated for answering your FREE question.

Jan 27, 2009 | 1999 Volkswagen Beetle

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

98 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honda Experts

yadayada
yadayada

Level 3 Expert

79865 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

Kevin Daniels

Level 3 Expert

1455 Answers

Are you a Honda Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...