Front Passenger Floor Heating up - Bad catalytic converter? (1 Viewer)

[ClassyJalopy]

Wife complaint about the area under her feet heating up to unbearable levels. The heat is radiating from the floor and comes through the carpet and the weathertech mats! I looked underneath and the right side catalytic converter is right below the footwell.
My first instinct is to just add additional insulation under the carpet but I am concerned if the cat is even supposed to heat up to this extent? The heat shield on the cat are rusty and held on by hose clamps.

Also, just in case it might be relevant, about 3 weeks ago I had a local shop replace the tiny flex pipe that was leaking. Could that be somehow related?

 

[gatormark91]

Exhaust leak or plugged cat. Check that the exhaust isn't touching anything on the chassis. Even a tiny leak at 800 degrees will bake feet.

 

[ClassyJalopy]

Exhaust leak or plugged cat. Check that the exhaust isn't touching anything on the chassis. Even a tiny leak at 800 degrees will bake feet.

Took it in to a muffler shop this morning. No exhaust leaks anywhere! I even went under the truck myself when they had it on the rack. The heat shields on both cats are rust but all in one piece and clamped on solid with the hose clamps. There are also two aluminum shields right above the cats that attach to the underside of the body and those are in great shape too!

Should I just add insulation and padding on the inside and call it a day? Could it be something else making my catalytic converters run extra hot? How do you check the cat temp?

 

[Eyedaho]

Took it in to a muffler shop this morning. No exhaust leaks anywhere! I even went under the truck myself when they had it on the rack. The heat shields on both cats are rust but all in one piece and clamped on solid with the hose clamps. There are also two aluminum shields right above the cats that attach to the underside of the body and those are in great shape too!

Should I just add insulation and padding on the inside and call it a day? Could it be something else making my catalytic converters run extra hot? How do you check the cat temp?

What Causes an Overheated Catalytic Converter?

If the catalytic converter is getting unburned fuel in the exhaust stream, it will combust in the presence of the platinum catalyst, causing excessive heat and damage to the cat. Check tech steam for fuel trims and O2 sensors, and scope the cat to look for damage. You can use an IR gun to check surface temps.

 

[HitTheDirt]

I had this same issue last summer on the way to and from Moab and though it was the cat etc. It was actually that I had turned on the rear fan to give my friend AC in the back, but the rear climate control was set on hot and we never realized it. The heat was incredible!! There was a disc brake rotor sitting on the floor by the rear console vents and it was so hot you could not even pick it up. It even melted my friend's shoe that was sitting back there. Also I rode shotgun while my other buddy drove and the passenger floor was super hot and uncomfortable. We had all these theories, and then my buddy tried turning off the rear fan and 30 min later, the heat was gone. The other poor bastard sat through about 10 hrs of unbearable heat for nothing

I suggest looking at this first, I was so relieved it wasn't something with the cat!

 

[Eyedaho]

I had this same issue last summer on the way to and from Moab and though it was the cat etc. It was actually that I had turned on the rear fan to give my friend AC in the back, but the rear climate control was set on hot and we never realized it. The heat was incredible!! There was a disc brake rotor sitting on the floor by the rear console vents and it was so hot you could not even pick it up. It even melted my friend's shoe that was sitting back there. Also I rode shotgun while my other buddy drove and the passenger floor was super hot and uncomfortable. We had all these theories, and then my buddy tried turning off the rear fan and 30 min later, the heat was gone. The other poor bastard sat through about 10 hrs of unbearable heat for nothing

I suggest looking at this first, I was so relieved it wasn't something with the cat!

That's a good thing to check! I guess the heater can probably get blasting hot in the summer!

 

[HitTheDirt]

That's a good thing to check! I guess the heater can probably get blasting hot in the summer!

I could not believe the heat coming out of the system, I was sweating like a pig in the passenger seat with the AC on high!!

 

[ClassyJalopy]

It is definitely not the rear heater! I have the truck interior completely stripped right now and it is very easy to see what is blowing what. I have the rear AC blasting icy cold air so it shouldn't be the issue.
I will check the fuel trims, I used to get P0171 code on and off but it has disappeared for a little while. The probe requires pulling an O2 sensor?

FWIW the muffler shop doesn't think the cats are blocked, and smack-the-cat-test didn't reveal any clunking so there doesn't seem to be any broken stuff inside either.

 

[HitTheDirt]

It is definitely not the rear heater! I have the truck interior completely stripped right now and it is very easy to see what is blowing what. I have the rear AC blasting icy cold air so it shouldn't be the issue.
I will check the fuel trims, I used to get P0171 code on and off but it has disappeared for a little while. The probe requires pulling an O2 sensor?

FWIW the muffler shop doesn't think the cats are blocked, and smack-the-cat-test didn't reveal any clunking so there doesn't seem to be any broken stuff inside either.

Ha! Bummer for you I guess then

 

[ClassyJalopy]

Checked temps with my new IR Thermometer. Ambient temp was 82 deg
- Bare Passenger floor was registering 160 deg
- Both Catalytic converters were at about 400 deg at the shields
- rear exhaust was emitting around 300 deg.

Are these in acceptable operating range? Do I just need to cover the top half of cat conv. with some additional heat shield to save the interior from cooking?

 

[jerryb]

I've only measured the 2" pipe, where it transitions to horizontal just before the bell where the cat/ heat shield is.
Never pointed at the passenger floor. anyway, i usually had 1150 F or so on the pipe. If you want I will check the floor shield above the passenger side on mine, it looks new and that side has no fiberglass wrap on it.

edit, thenut size is 10mm need a deep socket to remove the shields and either side can be removed without removing any pipe. I'd figure out why its hot though. whats the drivers side same location reading temp wise. That's one give away. Rear o2 techstream temp might show something weird, those should both be close to same and around 610-650.

 

[ClassyJalopy]

I've only measured the 2" pipe, where it transitions to horizontal just before the bell where the cat/ heat shield is.
Never pointed at the passenger floor. anyway, i usually had 1150 F or so on the pipe. If you want I will check the floor shield above the passenger side on mine, it looks new and that side has no fiberglass wrap on it.

edit, thenut size is 10mm need a deep socket to remove the shields and either side can be removed without removing any pipe. I'd figure out why its hot though. whats the drivers side same location reading temp wise. That's one give away. Rear o2 techstream temp might show something weird, those should both be close to same and around 610-650.

Thanks for the info. Both cats read around 400 degrees on the sheild that goes around the cat. There is another aluminum sheild above the cats attached to the body floor with 10 mm nuts.. I didn't read the temps there.
Both passenger and driver floors were reading 160 degrees on the inside right where front seat mounts to the floor!

 

[jerryb]

I was implying that you could measure where I have, or I could measure where you did. MAybe you have a hole at 12 oclock on the shield letting heat out. Maybe the shield at 12 oclock is the same temp as a regular running cat. Did you look at it with a mirror?

 

[ClassyJalopy]

I was implying that you could measure where I have, or I could measure where you did. MAybe you have a hole at 12 oclock on the shield letting heat out. Maybe the shield at 12 oclock is the same temp as a regular running cat. Did you look at it with a mirror?

Good idea! Will do later today

 

[ClassyJalopy]

As I have posted earlier, the cats on my truck get super hot to a point that I was reading about 160 F on the inside floor on passenger and driver side. The heat shields on the cats are rusty but still in one piece and the shiny aluminum heat shields mounted to the floors from the outside look all intact. I even had an exhaust shop confirm there is not leak in the exhaust anywhere.

Today I pulled the cats from my parts truck and was surprised to see there were no shields on them? Are they even OEM? would it be a good idea to swap out these with the one on mine to see if the heat issue goes away?

 

[ItGoesTo11]

As I have posted earlier, the cats on my truck get super hot to a point that I was reading about 160 F on the inside floor on passenger and driver side. The heat shields on the cats are rusty but still in one piece and the shiny aluminum heat shields mounted to the floors from the outside look all intact. I even had an exhaust shop confirm there is not leak in the exhaust anywhere.

Today I pulled the cats from my parts truck and was surprised to see there were no shields on them? Are they even OEM? would it be a good idea to swap out these with the one on mine to see if the heat issue goes away?

View attachment 2416920

View attachment 2416921

View attachment 2416922

Well...what did you ever find out?

 

[ClassyJalopy]

Well...what did you ever find out?

I ended up just putting extra insulation under the carpet to mask it for the time being.
I still need to replace the O2 sensors and get the fuel injectors serviced

 

[winecruiser88]

I ended up just putting extra insulation under the carpet to mask it for the time being.
I still need to replace the O2 sensors and get the fuel injectors serviced

Hi, I wanted to see if you have been able to come to our permanent solution. I’m having the exact same issue. We just came home from a camping trip where my wife sat in the back passenger side seat with the kids. Her feet along with anything on the ground were burning up.

I did notice that turning off the rear climate control helped reduce some of the hot air blowing on her feet (from the vent on the backside of the center console), but the floorboards were still majorly overheating. This is probably just because the air passing in the vents were getting super heated by the cat.

I know it’s not an exhaust leak because the overheating only occurs periodically. And all my heat shields are intact.

A while back I got an error code P0155 (bank 2/passenger side, sensor 1). I replaced the sensor, but I completely forgot to reset the ECU. I drove the car for quite a while after that point with the check engine light still on (

 

[winecruiser88]

A while back I got an error code P0155 (bank 2/passenger side, sensor 1). I replaced the sensor, but I completely forgot to reset the ECU. I drove the car for quite a while after that point with the check engine light still on (

My 19 month old accidentally hit enter before I could finish my post.

After replacing the sensor I drove with the check engine light on for all quite a while. It was at this point I noticed one occasion that the cat overheated on a long drive. It didn’t happen again for many months after. Then this weekend on a camping trip it was overheating almost the entire drive. This leads me to believe that bank to censor one is causing a bad fuel mixture and dumping excess fuel into the exhaust which is combusting in the cat.

I learned only then from a friend that I forgot to reset the ECU when I replaced the sensor many months ago. I did a reset, but the problem still occurs and the check engine light came back on. What’s really interesting though is that the new code is P0135 which is bank one sensor one, the driver side, not the passenger side.

Does anyone know if a bad bank one sensor can affect the fuel mixture going to the bank two side of the engine? I’m hoping it is a simple as replacing bank 1 sensor 1.

 

[ClassyJalopy]

First of all, the ECU relearns as you drive, so you don't really need to reset it. If you do want to reset it, then just take off the positive battery terminal for about 10 min and that should do the trick.

So in my experience putting the extra insulation took care of the immediate discomfort issue - no more burning feet! Ultimately, I think what ended up fixing the issue (i also had a p0171 error code) was replacing the intake gasket. Mine had a small leak in it that was causing it to suck extra, unmetered air in causing the ECU to notice that mixture was too lean. That made the ECU to dump extra gas in!

If you have Techstream or any other OBD II reader you can read short term and long term fuel trims. Take a picture of those readings and post here. The long term fuel trims should be close to zero (0). Non-zero long term fuel trims indicate whether the engine is running too lean or too rich.