Catalytic Converter Issues

[Clintusaf]

Hey all, I just picked up a 2014 Limited. I went to smog it here and Nevada and it failed(they only scan ODB2) due to codes. I have a generic scanner and get the following codes:

P0420 - catalyst system efficiency below threshold bank 1
P0430 - catalyst system efficiency below threshold bank 2
P0128 - Coolant temp below thermostat regulating temperature

I measured the temps (at operating temp and 2500 rpm) before and after the cats with an IR temp gun and got about 480 F before and 380 F after the cats, leading me they are both bad.

If cats are supposed to be lifetime products, what causes them to go bad on these?

For the thermostat, I’m assuming it has failed and gets stuck in the open position sometimes. Ive seen at normal operating temp before but sometimes it only reads cold when driving around town with enough time to warm up. I plan on replacing it very soon and I’m tracking the gasket should go on the outside (seems there has been confusion on which side its supposed to go on).

Anyway, any input on these issues mentioned above is much appreciated. Thanks!!

 

[ProjectSHO89]

If cats are supposed to be lifetime products, what causes them to go bad on these?

Usually, they get ruined from contamination due to excess fuel in the exhaust. Usual causes are misfires, vacuum leaks, and engines that are running too cold.

Since you have a P0128, it's likely your thermostat is stuck open and the engine can't get to full operating temp. Suggest replacing the 'stat, resetting everything, and crossing your fingers. You could try one of those "miracle in a can" products and see if it helps to "clean" your converters.

 

[Pete Deering]

Hey all, I just picked up a 2014 Limited. I went to smog it here and Nevada and it failed(they only scan ODB2) due to codes. I have a generic scanner and get the following codes:

P0420 - catalyst system efficiency below threshold bank 1
P0430 - catalyst system efficiency below threshold bank 2
P0128 - Coolant temp below thermostat regulating temperature

I measured the temps (at operating temp and 2500 rpm) before and after the cats with an IR temp gun and got about 480 F before and 380 F after the cats, leading me they are both bad.

If cats are supposed to be lifetime products, what causes them to go bad on these?

For the thermostat, I’m assuming it has failed and gets stuck in the open position sometimes. Ive seen at normal operating temp before but sometimes it only reads cold when driving around town with enough time to warm up. I plan on replacing it very soon and I’m tracking the gasket should go on the outside (seems there has been confusion on which side its supposed to go on).

Anyway, any input on these issues mentioned above is much appreciated. Thanks!!

? How many miles on the explorer?

Causes
1.Unburned Fuel.
2. Coolant Leaks
3. Oil Consumption.
The cat is warranty too 100,000 miles. See owners manual.

 

[Pete Deering]

Usually, they get ruined from contamination due to excess fuel in the exhaust. Usual causes are misfires, vacuum leaks, and engines that are running too cold.

Since you have a P0128, it's likely your thermostat is stuck open and the engine can't get to full operating temp. Suggest replacing the 'stat, resetting everything, and crossing your fingers. You could try one of those "miracle in a can" products and see if it helps to "clean" your converters.

I think you correct. If the engine doesn't reach operating temperature the PCM will adjust fuel to the engine temperature. That is why the 02s are not adjusting the fuel correctly. The cats are a results of the thermostat.
One step at a time.

 

[ProjectSHO89]

The converters have an 8/80 warranty in the US except for California which is 7/70.

 

[Clintusaf]

Usually, they get ruined from contamination due to excess fuel in the exhaust. Usual causes are misfires, vacuum leaks, and engines that are running too cold.

Since you have a P0128, it's likely your thermostat is stuck open and the engine can't get to full operating temp. Suggest replacing the 'stat, resetting everything, and crossing your fingers. You could try one of those "miracle in a can" products and see if it helps to "clean" your converters.

Thanks! Thats the plan for now. Any advice on whether to go with an OEM thermostat over an aftermarket one?

 

[Clintusaf]

? How many miles on the explorer?

Causes
1.Unburned Fuel.
2. Coolant Leaks
3. Oil Consumption.
The cat is warranty too 100,000 miles. See owners manual.

It has a 138K on it. Sorry I thought I had a signature block with that info when I created my account

 

[Clintusaf]

I think you correct. If the engine doesn't reach operating temperature the PCM will adjust fuel to the engine temperature. That is why the 02s are not adjusting the fuel correctly. The cats are a results of the thermostat.
One step at a time.

Makes sense and fingers crossed that is the case. I will post an update here after changing out the T-stat. Thanks!

 

[ProjectSHO89]

I'd stick with a Motorcraft thermostat. Just replaced mine as part of a WP replacement and general maintenance project, had to use a FelPro seal.

 

[peterk9]

It has a 138K on it. Sorry I thought I had a signature block with that info when I created my account

Welcome to the Forum.
You do. It's in the margin as well.

Peter

 

[Clintusaf]

Update: Replaced the Thermostat and seal with Motorcraft ones. My old thermostat was stuck open. After driving it some, the P0128 code is gone which is good. I still have both 420 and 430 codes. I have a cheaper craftsman code reader and cannot clear those codes with my code reader. I bought some of the O2 spacers to install. I installed the front one but havent gotten to the back one yet. One thing I noticed is the back side cat has already been replaced with a universal one and welded in. For now I am simply trying to pass the “smog test” so I can register the vehicle. The test If I need to replace the cats down the road I will. Just not wanting to spend that kind of money right now as I paid cash for the vehicle who had it registered in Arizona (no smog required there). Im hoping the codes will clear themselves on thier own after installing the O2 spacers and driving it a bit. Any suggestions or ideas from you guys on this?

 

[Clintusaf]

Another update: the last codes 0420/0430 have dissappeared after driving it for a bit so I will be getting it smogged today