Weewee

Hello everyone,

I'm a new member and I am glad I came across this forum; Looks to be a great resource!

I currently drive a 1998 Honda Civic EX which has just under 102k miles put it in. Two nights ago, the check engine light came on and I took it to advanced auto parts to have the code read. It returned a "P0420 - Catalyst System Efficiency Below Threshold Bank 1"

I'm wondering what is wrong and how can I go about testing the problem. How much would you estimate the repairs would cost?

Does anyone know if my cat converter is still under warranty?

I look forward to your input!

Thanks!

deving916

iTrader: (2)

Most likely bad cat, could be exhaust leak as well.

If your not worried about emissions (what state are you in?)

If your looking for a easy fix, to get rid of your cel then do this:


http://forums.evolutionm.net/evo-how...ouler-how.html

Weewee

I'm currently living in Minnesota, why?

kingmickez25

In the United States, emissions standards are managed by the Environmental Protection Agency (EPA). The state of California has special dispensation to promulgate more stringent vehicle emissions standards, and other states may choose to follow either the national or California standards.

Basically Depending on the state you live in They can let you get away with how much pollution you can throw in the air. If your state doesn't have a high requirement such as Ca You might not have to replace the catty for it to past state regulations thus making your repairs less expensive but your car will smell like gas alot

deving916

iTrader: (2)

What type of emission testing does your state do? I live in NY and they don't do smog testing. If your state does, I don't think that trick would work.

The P0420 means your cat is most likely no good.
You could buy another, but they are costly.


It depends on your situation. NY doesn't smog test, so the $5 spark plug non fouler trick saved me from spending hundreds on a new cat

deving916

iTrader: (2)

Exactly. In ca, they are very strict on emissions. Idk about your state, but Ny isn't too much.

Weewee

I did a little reading up and it sounds like the emission laws in Minnesota is pretty tight so the spark plug trick would do me no good here.

How much would a typical shop charge to have the catcon replaced? I looked some figures up and would $500 be a typical sum?

Is there any way I can tell if it is truly my catcon that is the problem?

If the catcon is the problem, why has my mpg plummeted by over 20% of the norm?

I really appreciate the input guys! Keep'em coming!

kingmickez25

I Found This thread by doing some searching It might be of some interest to you
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/replacing-catalytic-converter-1998-honda-civic-dx-mt-2400997/.

''if ur exhaust manifold is cracked or u dont pass smog just go to ur local honda dealer and they willl replace the manifold for free. but ur car has to be under 150,000 miles ''

Moving on to pricing it depends on a few things. There are catty's Ive seen go from anywhere 175.00-300.00 Plus.i your feeling cheap you can risk it and go to a pull it yourself junk yard and find a catty for around 100.00 I suggest you go to one of those review sites like yelp or something and find a garage offering a deal or that has a low labor cost. If done right it shouldn't cost you more then 500.00 with all the bells and whistles. If you want everything new and done by a dealer and such i would estimate about 800.00 max

98civdx

^It's illegal to sell/buy used cats.

It more then likely is the cat, but you really don't just want to go throwing parts at in an attempt to fix the issue.

Last year my buddy got the same code and IIRC the cat was the problem. Luckly, you have a EX so the cat replacement is very straight forward. I can't see it takeing a shop more then a hour, if even that to do the job.


If you have some tools/jack/stands this is definetly something that can be done in the driveway!!!

HondaPartsHero

I don't think Minnesota even has emissions testing any longer you should be fine
http://www.dmv.org/mn-minnesota/smog-check.php

From wiki

Under the Clean Air Act (1990), states are required to implement vehicle emission inspection programs in metropolitan areas whose air quality does not meet federal standards. The specifics of those programs vary from state to state. Some states, including Florida, Kentucky and Minnesota,[4] have discontinued their testing programs in recent years with approval from the federal government.[citation needed]

stockdohc

Okay I am new to the forum so I may need some guidance on this one. I have been reading up on this particular subject b/c my SI is throwing the same p0420 code. I can't add to what has already been mentioned, but mabey by explaining my situation we can help each other. I checked my spark plugs and my engine is runnning very lean, and I was wondering since my engine is running lean my ecu thinks my cat is bad? Another quick question. How could we check our o2 sensors to ensure thats not the problem?

beecee18

because most likely its not the sensor that will be the problem. And if it is it's gonna be the downstream (HO2S2)
The code simply illuminates after catalyst monitor has ran its course and tells the tech that the catalyst is below the threshold of effeciency. It could be possible that a exhaust leak between HO2S1 and HO2S2 could cause erronious reading at HO2S2(downstream O2)
cause the feedback of HO2S2 is what the catalyst monitor relys on.
That is why our cars have 2 O2's, the second one is simply there for catalyst effeicency, as this is one of the improvements of the OBD2 system.

99-2000 Si's are known for cats not lasting as long as they should.
I have a receipt from a honda dealership that replaced the cat on my EM1 70,000 miles into its completely stock life.

beecee18

its cause cali's liberal as hell. all above is correct

[/QUOTE]Basically Depending on the state you live in They can let you get away with how much pollution you can throw in the air. If your state doesn't have a high requirement such as Ca You might not have to replace the catty for it to past state regulations thus making your repairs less expensive but your car will smell like gas alot[/QUOTE]

Just replace the cat, sometimes the state of california also helps fix gross polluters vehicles with liberal programs. look into minn and see if these options exist.
If they dont this code does not affect the way your car runs PERIOD.

toconn

This screams O2 sensor to me and I don't understand why nobody seems to think so? What's different on Honda's than other cars? P0420 can mean your catalyst is bad, but more often than not it means your O2 sensor is giving false readings. Atleast take a multimeter to it before dropping hundreds on a cat.

beecee18

simply because throwing parts at your car is expensive and childish.

Hidenplanvew

he did say to test the o2 sensor.. GEt out the trustly DVOM

DSMAddicted

If you do more diagnosis/research and it turns out being the Cat, you can get it done for a couple hundred bucks including part and labor (most Hondas, at least).

Just go to Vibrantperformance.com, click on fabrication components, pick a generic ceramic catalytic converter of the right size (measure your exhaust with a caliper) and write down the part number (example: 7000 for 2").

Then go to Amazon.com and search for "Vibrant 7000" in Automotive. You have to select Automotive on the right otherwise you'll have to sort through a BRAZILLION cellphone accessories (the Samsung Vibrant running Android has similar name). You can buy it for less than $80 shipped. Take it to a good, reputable muffler/exhaust shop in your area and have them weld it in place for you. Small, family owned shops will do it for less than $100 in labour.

Good luck man.

stockdohc

I bought a high flow cat from Random Tech about a year ago, and had no problems until I added LUCAS fuel treatment to my gas just recently. The engine threw the p0420 code and then went off on its own. Now its back on, so I did some testing. The voltage on the o2 sensors match; therefore, I need to replace the high flow with stock. Could this problem be fixed without buying a new cat? Maybe I could do the fowler trick or tune the car to compensate?

beecee18

just reset the ecm by removing the negative battery cable for 10-30 seconds then reinstall it.
I would personaly do that and if the fault returns I would just wait and see if it extinguishes itself, dont put that crap in your gas tank just run the gas that already has it in there.
Run chevron and watch that light bounce!

jbpnoman

30 seconds isn't always long enough. What always works for me (and doesn't risk any electronics) is to disconnect the positive terminal, then try to crank the car. That discharges the capacitors within the ECU safely. It's the same concept to building a computer - disconnect the power, then try to turn it on to make sure all power is discharged.

Chevron, Shell, Exxon, just something that isn't bargain fuel. Nothing but Shell 93 touches my Civic, and nothing but Exxon/Shell 87 touches my cab.

beecee18

or just tap the brake pedal once,
this takes out any residual voltage also. but this above method sounds legit and makes perfect sense

you are correct about the fuel in cali here our only best choices are chevron shell and 76, these gasolines already have the additive in them for clean healthy engines.

Tkrizz

iTrader: (2)

Minnesota doesn't have you do any tests. Throw a test pipe on there and call it good.

pizton

I have this code on my 99 crv, Will the non fouler trick work? Can a complete noob like myself attempt and accomplish this? lol

94 IntegraLS

I had the same thing happen to my 98 civic and come to find lithe manifold was cracked right at the o2 sensor. I got a dorman replacement from eBay for 200 shipped. It included the exhaust manifold and a new cat. I did all the work myself which saved me a lot of money but I also found out at the time my whole exhaust had to be replaced which ended up costing more but I replaced the entire exhaust system for around 450 total. If you were to go that route, replacing the manifold would be much easier since you can cut the exhaust out in sections and remove it. I found it extremely hard to attempt to remove the front pipe from the cat since the bolts were just completely rusted on. If your interested though, here's the exhaust manifold and cat setup I bought http://item.mobileweb.ebay.com/viewi...id=66321913502

HondaPartsHero

Try it and report back. It's like $5 and a drill.