Chasing a po420 code 2tr-fe

SOLVED “new cat installed”


2007 Tacoma 2.7 2TR
As title states have a PO420 code
Bought truck with known blown head gasket put used low mile engine in it. HEAD GASKET WAS BAD ON EXHAUST SIDE. So plenty of coolant being burned and pushed out exhaust. Even when I drove it with known head gasket problem the code would only come on at random times
Have put about 50 miles on this new used engine and code had came in twice it’ll stay off for 20-30 miles then randomly come on mostly at higher speeds
What I’m trying to figure out here is any general test or should I just go ahead and buy a new catalytic converter assembly being the thing seen plenty of coolant via old engine
Or do I start with sensors being they are cheaper and if that don’t help do converter assembly.

 

The new very active sensor will only exaggerate things. The infamous po420 can often go away or at least time between CEL's can be greatly extended with cheap o2 extenders. Worth a try first.

 

I gotcha I just was worried if this cat was clogged up from all the coolant from the old Engines bad head gasket I didn’t want it having any negative effects on this motor which I’m sure it won’t or can’t, but just trying to cover all basis and check

 

A good burn off is to unplug the brake booster for a short time and introduce a vacuum leak at idle.

 

Most likely your cat is pooched from consuming coolant. A quick check is to check the inlet and outlet temp of the cat when everything is warmed up. The outlet should be hotter than the inlet. If you have a live data scan tool you can use that too. If the downstream O2 sensor looks like a sine wave then the cat is also pooched.

Honestly a P0420 code is one of the few codes that a guy can take at face value with no further diag.

Get either an OEM or certified cat or you'll be doing the job again toon

 

OK I appreciate it. I am seeing white smoke, but I’m not losing coolant or oil. It is just until the truck is warmed up. It reminds me almost of my old engine when the head gasket was blown, but like I just stated, I am not losing either fluid I almost want to believe that it is still stuff stuck in the catalytic converter But almost after 200 miles and it’s hard to believe. I am going to order a new OEM cat and two sensors and be done with it if I have a issue after that, then I have more things to worry about

 

You will likely need a new cat. One way to test to see if it's really plugged is to take it out and get the engine up to about 4k rpms at a low speed,(you will wanna use 3rd or 4th gear). If it starts to hiss and spit you will know it's clogged.

Your sensors are just fine... infact they are doing their job!

 

Replaced all is well thanks

 

Wow. Nice!