New catalytic converter for 2003 Mitsubishi Montero Limited


#1

Hi all,

We have a 2003 Mitsubishi Montero limited non-sport that has 175k miles and in our state we have yearly emissions tests. Our mechanic checked out the car after engine light came on. There are three issues with the truck and I need to know if its worth fixing or to trade it in toward a new vehicle.

  1. The car has a pretty serious oil leak or its burning oil. After about 1000 miles we have to put in 3 quarts of oil.
  2. There is a vacuum leak somewhere that is causing an error code P0131 to fire. Something about too much lean
  3. Error code P0431 fires and the catalytic converter is shot. Not a sensor but the full deal.

So my question is, in your opinion what would it cost to fix these issues or is it worth it to fix these issues?

Thanks,
Jeff


#2

Burning 1qt. of oil every 333 miles, it is not worth the cost of a converter, as I imagine even a new converter will be shot relatively quickly.


#3

The protocol is to fix the numerically lower codes first, so if you fix P0131 first it’s highly likely P0431 will go away.
Many good cat converters get needlessly replaced.


#4

The only serious question at the moment is where the oil is going. If it’s burning then the engine isn’t long for this world. If it’s leaking - well, it’ll be a mess so shouldn’t be that hard to find.

Neither of those codes tell you what you think they tell you. As circuitsmith noted, you ignore the P0431 until the P0131 is gone. The most likely cause of the P0131 is either a wiring issue for the bank 1 upstream sensor, or the sensor is bad. I’m just saying “most likely” - someone has to check it out.

In terms of actual programming, the P0431 is PROBABLY generated by comparing the upstream and downstream O2 sensor signals. I’m making an educated guess on that, b/c that is often how the “catalyst efficiency” codes are set. The 2 sensor readings are supposed to be different - because the cat is supposed to be cleaning the exhaust. But the computer doesn’t know why they’re not different. No surprise that an error might be detected if the upstream sensor is unhappy.


#5

Please clarify something. Do you wait until the engine is down by three quarts of oil and then add that oil then?


#6

Thanks for all your responses. Not to place blame but my spouse drives the car mainly. She has been trying harder the last little bit to add oil every thousand miles by checking the dipstick, but sometimes she waits until you can “hear it” the cloaking of the engine I assume. Which I know sounds awful. But hey what can I do.

Anyhow I had our mechanic looking at it today. As far as I can recall he said that the p0131 is being caused by an “O” rind somewhere down in a shaft or something. His thoughts were that it could be a simple fix but if not then some 700$ part would have to be purchased and the. Installed. Regarding the catalytic he agreed that once the first code was fixed then the catalytic could be addressed.

Yet, he mentioned that sinking 1000 into it and then finding out the catalytic is shot and then the situation with the disappearing oil all spell signs that this vehicle is dying and that we should probably consider off loading the car and getting a new one


#7

Since it’s been run low on oil and due to the oil question in general, I’d cut bait and run


#8

xeonjackson wrote:
Not to place blame but my spouse drives the car mainly. She has been trying harder the last little bit to add oil every thousand miles by checking the dipstick, but sometimes she waits until you can “hear it” the cloaking of the engine I assume. Which I know sounds awful. But hey what can I do.

It’s unfortunate that this hasn’t been made a priority. Saving sixty seconds every few days could easily have cost you thousands of dollars here.


#9

Guys, the cat is probably shot BECAUSE of the EXTREMELY high oil consumption . . .


#10

I’d be inclined to sell or junk it. Three’s just too many things going wrong.


#11

A junkyard or rebuilt engine is an option.
What shape is the body and interior in?


#12

The car needs to be dumped and more diligent care used on the next one. Waiting until the engine is rattling and then adding 3 quarts of oil is not a good automotive policy to abide by.

Continuing a policy like this is certainly going to lead to the next vehicle’s doom also.