Prejerism

Hey everyone I am wondering and going to ask a few questions about the code p4021.

Recently about a month ago my engine light came on. So I brand it down to the shop next to where i work we scanned the computer and came up with this code. [PO421:Warm Up Catalyst-below threshold (bank #1) CEL)

So I go ahead and change both o2 sensors thinking that is most likely the problem. Well it turns out it wasnt the problem. I have read that mitsubishi did a recall on this code and is replacing the catalytic converter for free. So I called the mitsubishi dealer gave them the last two digits of my vin and they said there is no recall on my car.

Whats wrong with the car?
I was thinking maybe the wrong fuel pressure so its flooding that cat?
I really dont know.

Also Does anyone really know where to get a good service manual for this car? its a 2002 mitsubishi lancer es manual transmissioon. I have looked around and searched but all i could really find was ebooks or for the mirage.

Can I get a book for the mirage?

Much help is appreciated. Thank you

blaze_125

iTrader: (8)

posting the mods on your car could be very usefull to troubleshoot your issue.

Manuals...
https://www.evolutionm.net/forums/la...able-here.html

Evo666

iTrader: (3)

Post your mods so we can assist you better.

Prejerism

Only mod I have is a k&n short ram air intake typhoon

Those manuals.. Could I use the 2003 manual for my 2002 lancer?

blaze_125

iTrader: (8)

Yes

darkmitsu

iTrader: (1)

ok here is an easy fix get a evo 8 ecu and do the force obd2 pass mod to it , and you are good to go and never have to worry about the cat , rear o2 sensor , or egr system again...

blaze_125

iTrader: (8)

And also never know if they actually fail?

Prejerism

this isnt a car i would really want to mod up on just a car to get by with.. Im going to check the fuel rail pressure.

brokeazzlos

iTrader: (4)

you need a converter!
why do you try to repair other stuff you don't need to.

the only fix is a converter. end of story.

Prejerism

yeh but why is the converter going bad there has to be a reason for that

blaze_125

iTrader: (8)

because that's what they do?
They work, then go bad.

EvolutionESX

There are two ways a converter can fail:

It can become clogged.
It can become poisoned.


There really is no "inspection port" for the consumer or mechanic to see an actual clog in a converter. Often, the only way to tell if a catalytic converter is malfunctioning (plugged) is to remove it and check the change in engine performance. When a clogged converter is suspected, some mechanics temporarily remove the O2 sensor from the exhaust pipe ahead of the catalytic converter and look for a change in performance.

A catalytic converter relies on receiving the proper mix of exhaust gases at the proper temperature. Any additives or malfunctions that cause the mixture or the temperature of the exhaust gases to change reduce the effectiveness and life of the catalytic converter. Leaded gasoline and the over-use of certain fuel additives can shorten the life of a catalytic converter.

A catalytic converter can also fail because of:

Bad exhaust valves on the engine
Fouled plugs causing unburned fuel to overheat the converter
*Sometimes you can tell that a converter is clogged because you don't go any faster when you push the gas pedal. Also, there usually is a noticeable drop in gas mileage associated with a clogged catalytic converter. A partially clogged converter often acts like an engine governor, limiting the actual RPMs to a fast idle. A totally clogged converter causes the engine to quit after a few minutes because of all the increased exhaust back pressure.

Prejerism

Thank you evolutionesx. One more question. Like i been saying about the fuel rail pressure regulator could that even be the problem? What if thats the reason the cat has gone bad because the regulator is flooding the cat. Just wondering here helping myself understand alittle bit more