Mitsubishi Eclipse 3G Club banner
1 - 11 of 11 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter · #1 ·
I've had the code for about a year now. Car has 160k miles on and here recently I've done some research about it. It could be the Catalytic converter, O2 sensor, or a fouled sparkplug. The car doesn't have a miss, an when I turn the CEL off the code comes back up after about 15 minutes. I've replaced the downstream O2 sensor and it did nothing. So if it was the Cat which one should I replace? I've deleted the cat attached to the manifold,but I've had the code before I done that. Could deleting that Cat cause this or is it the Cat that's about 3/4th down from the car? Please HELP!?! Btw the code says Warm Up Cataylst Below Threshold Bank 1 (p0421)
 

·
Registered
Joined
·
12,548 Posts
You will get PO421 with a gutted front cat. Chances are the sensor was originally bad, the cat was not. Then you deleted the cat and put in a good sensor and now you're throwing the code because you have no cat. You would have to put in a new front cat to get rid of the code or try to trick the o2 sensor into thinking there is one with a spark plug antifouler.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #3 ·
You will get PO421 with a gutted front cat. Chances are the sensor was originally bad, the cat was not. Then you deleted the cat and put in a good sensor and now you're throwing the code because you have no cat. You would have to put in a new front cat to get rid of the code or try to trick the o2 sensor into thinking there is one with a spark plug antifouler.
Do you have a link or example on how to trick the sensor? I've heard about this before just never acknowledge it before. Thanks for the help!
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #7 ·
Okay will it throw any other codes if a take the downstream sensor out of the exhaust flow? (Using the trick) I know the upstream sensor will throw the code p0134 if I use the fouler method.
 

·
Registered
Joined
·
22 Posts
from what i read that code is for the O2 sensor in front of your car. And you dont completely take out the o2 sensor. you just add the fouler
 

·
Soon to be 4G64K-T!
Joined
·
561 Posts
The sensor at the header is the one that measures fuel trim. The rear sensor measures the nox and emissions. Put the anti-fouler on the rear and you're set
 
1 - 11 of 11 Posts
Top