How I Figured Out Exhaust Restriction (Clogged Catalytic Converter)

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Publicado 2018-08-21

In this video I'll show you how I figured out that this 2001 Ford Escape 3.0L had an exhaust restriction or a clogged catalytic converter. I started by connecting a vacuum gauge to the intake manifold and measured the vacuum present when the vehicle was at idle. Usually a normally running engine will have somewhere around 18"-22"hg of vacuum at idle. I had around 12"hg at idle. I also revved the engine and held the throttle at around half throttle. When I did this the vacuum immediately went down to 0 and stayed there. On a normally operating engine the vacuum would go down initially when opening the throttle but is would quickly go back up. As mentioned the vacuum stayed at 0 when the throttle was held. So, I knew I had a restricted exhaust. The next step was to find out where the restriction was. I suspected a common restriction just because of the very poor performance of the engine. But, for grins and giggles I checked the cat converters by removing the O2 sensors and inspecting them with a bore scope. I did not see anything obvious so the next thing I did was run the engine with the bank 2 sensor 2 oxygen sensor taken out. Both the front head and the rear head are joined together by a "Y" pipe so removing this O2 sensor would alleviate any back pressure for both heads. (Note: You have to be very careful when doing this as you can damage your vehicle by exposing parts to the extreme temperatures of the exhaust gas that will come out of any O2 sensor port. You could even catch the vehicle on fire. If your O2 sensor port is in an enclosed area and exhaust cannot be safely vented from said exhaust port without damaging close by parts or catching the vehicle on fire then It would be my suggestion to NOT DO IT! Try finding the restriction by some other means such as taking sections of the exhaust of and inspecting sections internally with a bore scope.
USE THE METHOD OF RUNNING THE VEHICLE WITHOUT AN O2 SENSOR IN AT YOUR OWN RISK!! YOU CAN DAMAGE YOUR VEHICLE AND START A FIRE!! Also Note: I had to remove a splash shield so that it would not become damaged) Back to my story.... So I ran the vehicle without this O2 sensor in and it ran very well. So, I had a restriction in the exhaust that was common to both banks of the engine. Back cat, the cat converter after the two front cats, was suspect. Conveniently the back cat has a flange just in the front of it. I disconnected this flange and there it was. Cat converter material from the front cats had clogged the exhaust at this location. New converters and cleaning the material from exhaust was needed. And that's it in a nut shell.

Note: keep a fire extinguisher near by in case of fire.

Now, this video just shows how I discovered that the exhaust was clogged on this particular vehicle in this particular way. Though I show some diagnostic techniques this video is not comprehensive when It comes to showing you how to properly diagnose your vehicle. The video has very good information but it is not comprehensive. I would suggest using a repair manual.

Also, as a rule of thumb, I would suggest waiting at least an hour before handling exhaust and exhaust components after the vehicle is ran. If you don't you could end up with a very serious burn.

Also, It is good to note that there is usually a root cause of the exhaust becoming restricted. So, further diagnosis may be needed.

DISCLAIMER
Barbour's Auto Help is not responsible for any damage or personal injury incurred in the process of performing any auto repairs done by you the viewer. Automotive repair is extremely dangerous. Repair your vehicle at your own risk. It is the viewers responsibility to verify all information and procedures as outlined in YOUR REPAIR MANUAL AND OWNERS MANUAL FOR YOUR VEHICLE. Owning and using a repair manual suited for your vehicle is essential for correctly and safely performing ANY repair to your vehicle. Always wear safety glasses and heed all instructions for use applicable to any piece of equipment you may use. Due to circumstances out of the control of Barbours Auto Help, Barbours Auto Help makes no guarantee that by the use of the information given in this video a quality repair will be made. Barbour'sAutoHelp makes no guarantee that the information provided is totally complete, syncronized and accurate. Verify everything using an appropriate repair manual. Follow the repair manual over this videos content. You can do it. Do it right and do it safely.

Repair your vehicle at your own risk! Barbour's auto help does not guaranty a proper repair using these techniques.

Todos los comentarios (21)

@Rakki_Haitatsu hace 11 meses

Something that alot of catalytic converter videos won't tell you is that when you have two catalytic converters as opposed to one, you're going to have different symptoms. Check both cats with a laser heat gun and check temps at both front and back of cat underneath the heat shield. If there is less heat on the back side than the front, Chances are it's clogged
@ShahidVelji-uk1bz hace 1 mes

Hey I wanted to say thank you very much for this informative video. I have been dealing with this check engine light in my vehicle and every videos I see they say the same thing “it could be a bunch of things but most probably it’s your catalytic converter”, but you are the first person who actually takes the time to show what a clogged catalytic converter looks like, and from this I now understand why check engine lights can be thrown. Thank you very much this was very helpful and informative.
@andreyzagoruyko5390 hace 1 año

Neat, haven't seen a video yet where it's all apart and in pieces to see; very valuable thank you!
@kylefowler5082 hace 5 años

Great video, I wanted to add an early sign of cat problems can also be cylinder misfire codes. My poor friend replaced his coil packs twice before he figured out the cats were falling apart when the car couldn't do anything more than idle before dying!
@lasers4less hace 1 año

Great Detective work. Thanks for posting this.
@servihomestead4324 hace 3 años

Very helpful and well-done video. Thanks for sharing. I'm about to try this on our 09 Nissan Quest.
@tauruscarclubphoenixaz1425 hace 5 años

Wow right on point!!! I had boulders falling out along with some coal it looks like charcoal but runs wwaayy better now mind my car has 300k on her and of course is a taurus has pep in the step now and my rpms ain't shooting up after launching
@wilborth5th hace 5 años

Now this is a great video, I see people including myself looking for vacuum leaks everywhere and sure enough never to be found, and then is the pipes that are full of debris from cats converters, unbelievable, thanks for sharing
@steveblottenberger1097 hace 3 años

Good job partner you were very feral and you can understand you keep up the good work I got the same problem with my Nissan Pathfinder bogging down take the exhaust apart and check it
@oby-1607 hace 5 años

I have a 2008 Escape with the 3.0 engine. I will be checking the back cat and probably may have to clean it out. When they melt like that, I don't know how the engine can breathe. Thanks for sharing.
@jinglesalas hace 3 años

I just discovered this exact thing on my 2001 toyota sienna xle. Engine power was nearly non existent. Removed the front wideband sensor and power returned. Separated the exhaust right before the final catalytic converter and the same stuff you showed in your video fell out. I knocked it all out of there and reconnected everything. The van has very good power now, and it has not thrown a CEL yet. Kinda strange. BTW, I have over 350,000 miles on this van.
@jookiva hace 4 años

This video helped alot especially the trick to remove the oxygen sensor to see if your pipe is clogged or not! Thank you!
@davebarajas5308 hace 5 años

It appears that your exhaust pipes had honeycombs for breakfast. Nice video
@anthonybrown3481 hace 1 año

Thanks for the video. Very very useful info.
@doctorofparadox4469 hace 5 años

Keith! Cool Channel. I believe that I have a restriction in the same place on my Lexus Rx 300.But, I used an infrared thermometer to check temp differences on various exhaust system components. The temperature at the entrance to the third cat (primary muffler), was >600F:whereas nothing else on the exhaust exceeded 400F. Iv'e changed everything myself and the truck still bogs down upon acceleration with random misfires throughout - no specific. Doesn't seem to have any exhaust leaks, but I'm about to create one by pulling the rear O2 to see if it runs like normal - slightly louder though. I saw you video then I saw you! Fantastic. - Keep in touch - Greg Totty
@CHIBA280CRV hace 4 años

Wow that is me clogged cat 🐱 , thanks for the informative video.
@TomBuikema hace 4 años

THANK YOU SO MUCH. I changed everything on my car trying to figure out why my acceleration and top rpm sucked. Your video is the only one I found that illustrates the same engine behavior that mine had.
@therockwhispers hace 1 año

Thanks for your video. I had water in my catalytic converter and a lot a honeycomb I was wondering what causes them to go bad this was less than a year old?
@TheTrooperGirl hace 2 meses

Great information and a wonderful refresher.
@dianeprice1153 hace 9 meses

Thank you thank you for your video just confirms what I knew was going on with mine the same thing in my 06 Dodge Charger you just save me a lot of money you saved me from getting a motor