P0420
#1
P0420
New to the forum. Completed install of BEGI turbo/IC (7psi boost) and EnthuzaCar exhaust (including downpipe with Cat) in September. Car runs great (no misfire, no ping, etc). Last week for the first time, got a CEL that persists resetting and mechanic says p0420 code means non OEM Cat and he has no solution short of "get used to it". I'd really like to get the CEL off on a more permanent basis. Jason at EnthuzaCar suggested posting question here. Any ideas? Thanks.
#6
Pickleking, read my post here: https://www.miataturbo.net/forum/t29945/#post348921 .... works great. My car is a 2004 so the wire colors should be identical to yours.
#7
Senior Member
iTrader: (23)
Join Date: Oct 2009
Location: Chatsworth, SoCal
Posts: 948
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Quick before someone gets their chones in a bunch. Post in the noob section and denoob your self. For your own sake heed this warning. Also learn to use the search function it is a great help. There is also Miata.net that has tons of info. Between the two sites you can have a solution to just about any question you may have.
Welcome and enjoy. Some will bite prior to asking questions. However this is a good bunch of people.
Have a great day,
Jared
Welcome and enjoy. Some will bite prior to asking questions. However this is a good bunch of people.
Have a great day,
Jared
#11
The thing is, that CEL code doesn't mean there is anything wrong with your cat or exhaust, it just means your cat or exhaust is less efficient (a.k.a. "better" in performance terms!) than what your ECU expects.
The only way to "fix" it is to put in some restriction (like a crappier cat/exhaust) or to change the input that the ECU sees. My way does the latter.
The only way to "fix" it is to put in some restriction (like a crappier cat/exhaust) or to change the input that the ECU sees. My way does the latter.
#14
Slowest Progress Ever
iTrader: (26)
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 6,022
Total Cats: 304
I used an O2 simulator that I bought from O2 Simulator, E-commerce
Then I took an old O2 sensor from the junkyard and cut the pig tail off and soldered the simulator in place so it was total PNP. I think that website also has wiring diagrams, if not, ask me and I can provide. I was having the same problem when I first went turbo, as I no longer had a cat.
Then I took an old O2 sensor from the junkyard and cut the pig tail off and soldered the simulator in place so it was total PNP. I think that website also has wiring diagrams, if not, ask me and I can provide. I was having the same problem when I first went turbo, as I no longer had a cat.
#16
What evank suggests, works. You're other option is to offset the O2 sensor another 1/4" to 1/2" from the pipe. But that might throw a different CEL. So, do the resistor mod. We've done it before. It works.
https://www.miataturbo.net/forum/t29945/
Stephanie
https://www.miataturbo.net/forum/t29945/
Stephanie
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