187Chor

Had a friend plug in the handheld diagnostic tool...
it reads - P0420 Catalyst System Efficiency Below Threshold (bank1)

Does anyone know(not guess) what is wrong with my car?

Axix24

02 sensor or cat issue. Clear it and unhook the negative cable of battery and see if it comes back.

mustclime

you can also pull the ecu fuse in the fuse box under the hood...leave it out for about a minute....this way you do not loose your radio tune setting.....


Just a thought...some people I know have had some good luck with carbon cleaning that some jiffy lubes do clearing out cats and o2 sensors...

187Chor

So that engine light been on a couple weeks i figured if i just need a new cat theres no rush, but ive noticed in the last 3 times i filled my tank ive been getting alot less km per tank.. alot meaning 3 fills ago i got 550km before the gas light came on. Yesterday it came on at 390km. Also i feel a significant decrease in power when accelerating at slower speeds. The car feels sluggish overall. An hour ago the maint req"d light turned on.
What do i do?? Is this just the cat? Where can i buy an oem style hiflo cat? Specific brand plz. Dont say search ebay

mustclime

guess what...you kmpk is going to suck....your ecu is not seeing good readings from the o2 sensors so it dumps gas to reduce co and make more "good" co2....welcome to the 21st century....did you even try the carbon cleaning? if thats is to scarry, just get a stock replacement flowmaster cat....or pay for the gas. think I do not know what I am talking about?...real simple, pull a spark plug...they will be full carbon black. By dumping gas through the injectors, the combustion process is cooled....cool= co2...hot and lean = co....ecu knows co = bad for the world so it runs rich.....just like honda told it to.

187Chor

Yes i suspected that its running rich. I also think the plugs might be fouled now and might be misfiring and causing the intermittent power. I am going to change the cat asap. Should i change the plugs at the same time?

mustclime

clean them....if they have more than 50,000 miles on them...change them....do not get junk plugs....denzo...Iridum(sp).......

187Chor

Ok so i tried the carbon cleaning fuel additive... it made a slight change but not for long. By the time i went through another tank it was sluggish again. Ive ordered a hiflo oem style cat, waiting for delivery. Went ahead and changed the plugs today. Cdn tire and part source didnt have ngk in stock i got stuck with bosch platinum. I hope they are ok. The car definately drives better, and with the new cat in by next week id assume it will run even better.
i went to honda for a quote on the cat and was told $2288.69!
I dont even think thats included installation

187Chor

So i put the magnaflo cat in today and the car doesnt seem normal its still slow. Im hoping it is because it was really hot out today. The shop turned the check engine light off but it still says maint reqd. They said it has nothing to do with the check engine issue.
Will it take a while before the ecu goes back to normal and stops making a rich mixture? Or should that have happened when they turned the light off?

b_ron

I have the P0420 code come up pretty often (usually when i push the car, or every month or so). When it comes on, my car feels like it's restraining itself (need more gas to get to the right rpm than normal). I have a scan gauge so I clear it every time it comes on. It goes back to normal after i turn off the light.

Im set on it being the cat...

187Chor

The car seems to be running fine now.. no lights popping up.. throttle response seems restored.. drove to wasaga beach and back yesterday no problems..

187Chor

something I have noticed though in the last 2 fillups i'm still not getting good mileage, im getting around 500km per tank when I used to get 550-580 consistently...