420code

420code

Postby Cologne [OP] » December 27th 2009, 12:48pm

taking my ride into shop soon for a 420 code. What should i b aware of?
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Re: 420code

Postby evil_motors » December 27th 2009, 3:35pm

looks like your van was getting high :obscene-smokingpimp: :obscene-smokingred: :obscene-smokingsombrero: :obscene-smokingweed: :obscene-smokingjoint:
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Re: 420code

Postby rev_les » December 27th 2009, 6:52pm

bad catalytic converter. p0420 is catalytic converter efficiency below threshold. Make sure you have good fuel,no engine miss,etc. It amazes me that with no cat at all, I very rarely have that code pop up!Before you go to replacing the cat, make sure the engine's well tuned and running right.
I'd erase the code and see how long it takes to pop up again.
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Re: 420code

Postby Cologne [OP] » December 28th 2009, 4:59am

lol! Thanks for the reply u guys.

My egr & cat only have about 30K on them. But my No. 1 cyl. fouls flugs pretty fast. Im going to change it out again tomarow before i take it in. I have been fouling that plug for a long time but never got a 420 code. I always got a missfire code.

Thanks again. PS HAPPY HOLLIDAYS :)
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CARBON IS THE KILLER! Know this...
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Re: 420code

Postby Cologne [OP] » February 7th 2010, 1:51pm

Took it in to shop. They told me its the cat. ? I didnt replace it because its pretty new along with muffler. Any other ideas?
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Image cutout back of front wells + 4" bump stops.

CARBON IS THE KILLER! Know this...
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Re: 420code

Postby gtkane » February 7th 2010, 2:33pm

Every shop will tell you that it's the cat, because it is. Now you have to repair the source of the fouling plug because that is what killed the cat.
Converters never die...they are allways murdered.
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Re: 420code

Postby astro355 » February 7th 2010, 4:52pm

gtkane wrote:Every shop will tell you that it's the cat, because it is. Now you have to repair the source of the fouling plug because that is what killed the cat.
Converters never die...they are allways murdered.


Yep, what he said. Can you take a picture of the fouled plug?

If not, do you lose coolant or oil?
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Re: 420code

Postby Bread Van » March 21st 2010, 11:43pm

Run a couple of bottles of RXP through the system and find out what caused the fouling (actually reverse that order). I've had great luck with the RXP unless the cat is plugged or crumbling. If it's stubborn put 3 cans of RXP in a full tank of premium prior to a long trip.
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Re: 420code

Postby Cologne [OP] » August 14th 2013, 12:31am

I finally found the source of all the probs Ive had. This post is pretty old and I cant remember what I did for the 420 code. But I did put a high flow cat on since this post. So that might have been the fix then. BUT! Ive learned the hard way that Carbon build up was the source of most all my problems. And it was all like domino's. One thing ruined another thing and so on and so on...

CARBON! is the killer. It fouled plugs that killed cat. It fouled EGR valve and finally clogged EGR valve intake passage on the manafold.

Ive spent over a thousand bucks on parts because of a smog device. !!!!! :screaming: :banghead:


Now just spent $1000. to have manifold cleaned up. It was a carbon garden.
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