Diagnosing a Failed Emissions Test - High HC, CO and NOx Causes and Repairs

In this video I go over how you can diagnose excessive amounts of Hydro Carbons (HC), Carbon Monoxide (CO) and Nitrogen Oxide (Nox) in your exhaust. I go over how a rich or lean condition can cause one or more of these gases to be high and therefore causing you to fail emissions. Also I go over some components like the Catalytic Converter, Oxygen Sensor (O2), Ignition Coils, Spark Plug Wires, Spark Plugs, EGR Valve, which are part of your emissions systems on your car and how they effect different levels of each gas.

Here are some other video's you may find interesting:

If this video helped you out please don't forget to subscribe, give it a thumbs up or if you are feeling generous leaving a tip by clicking the " i " button on the top right corner of the screen. Thank you very much for your support!

Disclaimer:
Due to factors beyond the control of Ratchetsand Wrenches, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Ratchetsand Wrenches assumes no liability for any property or personal damage that may arise from doing a repair on your vehicle after watching any of my repair video's. Due to factors beyond the control of Ratchetsand Wrenches, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Again Any injury, damage or loss that may result from improper use of tools, equipment, or the information contained in this video is the sole responsibility of the user and not Ratchetsand Wrenches.

[wysetech]

I have been an automotive tech for 47+ years and that has to be one of the best exhaust emission explanations I have ever seen anywhere.  I just subscribed to your channel.

[johnneszmery]

This is the best resource ever!! Using this knowledge, today my 1990 Volvo 240DL with 246K miles passed with flying colors! The mechanic/tester was amazed at the low numbers. I've subscribed and thanks for everything, Man !!

[osielzamora]

Thank you for your videos, you have a great way of putting all repair in a simple and clear manner. Coming from a person who has 24 year of automotive service . 👍🏽

[apuuvah]

Very informative, thanx. Especially liked...

1) If NOx is a pass at idle, but a fail at higher rpm, EGR valve is faulty
2) If NOx is WAY above the limit (2-3x or more) catalytic converter is busted

[BellaRocko]

You make excellent informational and DIY videos!  It's clear that you have a very good understanding of all auto related functions by how well you can explain them.  The only thing that confuses me is why you don't have hundreds of thousands or millions of views and subscribers!  Thank you very much for your videos!

[c.c.]

thanks for straight answers with no frills, some people are just unable or unwilling to do that and wastes everyones time.

[lanazaakat]

Please also keep in mind to use simple language for the common persons who don't have much auto experience and can't find an honest mechanic, especially in these times. . Thanks !! Good Job. I was able to change the timing belt, water pump, all pulleys etc. just by watching your videos and taking notes. !! My 1997 Camry 2.2 L now runs like a charm. I just passed smog. Time, knowledge, and tools are what one needs...Appreciate.

[wilsonbent]

great video man... the way you explain poor test results to the problem is phenomenal! thank you

[jag]

I’m sold man. You are way above my pay grade!!!! Thanks and as a diy guy, I appreciated the information.

[jesusgastelum]

I never comment or even subscribe. But I subscribed awhile ago. Ever since I was working on my Audi. You've saved me numerous times. Great work sir!!!

[meperson]

I had issue with high hydrocarbons on my 1995 Toyota Corolla. I followed your instructions and replaced spark plugs and the problem was solved. Just for a good measure I used engine cleaner, put a new high mileage oil and high quality gasoline. Passed the DQ without any issues. Thank you very much!

[jonnapatricia]

It’s a great and reliable video. Was facing this kinda issue back then with my emission test so I had to look for a way, which was how I came across Stray Admin who has got years in experience of helping lots of citizens pass they’re Smog test too.

[testplatform]

Thanks so much for sharing this info. You probably have saved hundreds of people from dishonest repair shops.
More power to you Bro!

[joelmccoin]

Excellent Video!!! Very well explained, very clear, helpful & useful. You are a good teacher, Thank you.

[johnevon]

This is really great information for the consumer, Thank you for your time and effort in putting this all together.

[omnidivisible]

Superb presentation. Good thing that I saved my emissions reports. Now I can use the information I learned from you and use the emissions reports to troubleshoot and maintain my car.

[TwoCarGaragez]

I always replace everything that’s cheap first. Check for vacuum/air leaks and exhaust leaks. Change your engine oil and oil filter. Change your air intake filter if it looks old. Change the O2 sensors. Add some Lucas fuel cleaner. Check your tire pressure (can make a difference on dyno smogs). Lastly, take it for a 20-30 min highway drive before getting it smogged. Leave it running until it’s tested.

[nathanaelnewton]

Very clearly explained-It just shows how a good explanation does not require all the other 'how great am I' platforming BS. Well done and thank you.

[ArelSprite]

You should be a professor in YouTube university
This was the greatest Emissions video I’ve ever seen

[richardpotter]

Very good explanation. One other point is that if you have a thermostat that is stuck open and the engine runs colder than it should, the EMS will over compensate the fuel mixture and the engine will run too rich thus increasing the Co2 levels.