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P0420 Code Question

 
  #21  
Old 08-22-2018, 06:50 AM
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Just fyi guys. If you guys need cats. I have them available. Just pm me and i will get you a price for them. I also have a mis fire in cylinder 3. It was oil.

The Dr!
 
  #22  
Old 08-22-2018, 10:16 AM
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Originally Posted by Dr dome View Post
Just fyi guys. If you guys need cats. I have them available. Just pm me and i will get you a price for them. I also have a mis fire in cylinder 3. It was oil.

The Dr!
where does the oil come from? and what is the fix?.....bad valve cover gasket?
 
  #23  
Old 08-22-2018, 10:25 PM
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iownme, based on other posts I’ve read in the forum it comes from leaking valve cover gaskets.
 
  #24  
Old 08-23-2018, 01:42 PM
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Originally Posted by xjagRI View Post
iownme, based on other posts Iíve read in the forum it comes from leaking valve cover gaskets.
good to know.
thanks
 
  #25  
Old 08-23-2018, 02:20 PM
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Originally Posted by xjagri View Post
iownme, based on other posts iíve read in the forum it comes from leaking valve cover gaskets.
usually imt orings. The back lower one drips right on the exhaust. But hey while you have it all offreplace it all cause theyre all the same age and mileage
 
  #26  
Old 09-01-2018, 08:17 PM
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I was finally able to do the upper and lower intake gaskets, valve cover gaskets, plugs and coils. Took about 7 hours with plenty of breaks and a slow pace. I used Felix pro gaskets, iridium ngk plugs and used OEM coils. Thought I’d have the biggest problem with the rear valve cover gasket, but turns out that one was not leaking onto the plugs. The front one was. I replaced them both anyway. I hope I put everything back where i5 goes...

I’ll test it tomorrow and find out.
 
  #27  
Old 09-02-2018, 08:40 PM
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All done. Test drove it today. All seems right. Some residual burning of the oil run off and cleaners used that ran onto the engine block, but no more bucking or jerking as from the misfire. Seems like it is doing what it should.
 
  #28  
Old 09-03-2018, 01:18 AM
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Last thing to do now - check fuel trims once they've had a chance to settle.
 
  #29  
Old 09-09-2018, 07:29 PM
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So far, so good. P0305 and P1315 are gone. Fuel trims look good. No leaks so far. P0420 still there, but it has been intermittent. I still think the misfire caused the Catalytic Converter to get gunned up. Now that it is fixed, I’ll try to “clean” it again and see if I can get it to go out again. We’ll see.
 
  #30  
Old 09-10-2018, 08:46 AM
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check if theirs a leak at gaskets at the cats ,other wise you may need a new cat
some people has had luck running seafoam through the vacuum of the brake booster to clean cat if its minor
 

Last edited by dennis black; 09-10-2018 at 12:14 PM.
  #31  
Old 10-05-2018, 10:33 PM
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Latest Update:

Everything seems to be working fine. As of today the MIL has been off for a month. I utilized the advice of dennis black and some other posts I saw on the forum and used seafoam. However, I used it differently.
  • First: Used half a bottle of seafoam spray directly in the catalytic converter. I took out the upstream O2 sensor and used an endoscope to look down into the CAT. I saw that the media was in good shape, but looked dirty. As stated above, I think it was form the contamination and soot from the misfire on #5. The seafoam spray came with a long spray straw that let me a good position and move the end around to get as much coverage as possible.
  • Second: I got a narrow hose and poured about 1/2 bottle of liquid seafoam directly into the CAT.
  • Third: Drove the car 3-4 miles to a remote parking lot.
  • Fourth: Sprayed the rest of the seafoam spray into the air intake (found a video on YouTube).
  • Fifth: Poured the rest of the liquid seafoam into the brake vacuum tube who,e car was running (like done in you tube videos and in advice from the forum.
  • Sixth: Let it smoke like a forest fire.
  • Seventh: Drove it for 40 mile then and reset the OBD code.
It it has been clear ever since. I’ll keep you posted if things change. Wish me luck!!!
 
  #32  
Old 12-07-2018, 12:37 AM
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Originally Posted by xjagRI View Post
Latest Update:

Everything seems to be working fine. As of today the MIL has been off for a month. I utilized the advice of dennis black and some other posts I saw on the forum and used seafoam. However, I used it differently.
  • First: Used half a bottle of seafoam spray directly in the catalytic converter. I took out the upstream O2 sensor and used an endoscope to look down into the CAT. I saw that the media was in good shape, but looked dirty. As stated above, I think it was form the contamination and soot from the misfire on #5. The seafoam spray came with a long spray straw that let me a good position and move the end around to get as much coverage as possible.
  • Second: I got a narrow hose and poured about 1/2 bottle of liquid seafoam directly into the CAT.
  • Third: Drove the car 3-4 miles to a remote parking lot.
  • Fourth: Sprayed the rest of the seafoam spray into the air intake (found a video on YouTube).
  • Fifth: Poured the rest of the liquid seafoam into the brake vacuum tube who,e car was running (like done in you tube videos and in advice from the forum.
  • Sixth: Let it smoke like a forest fire.
  • Seventh: Drove it for 40 mile then and reset the OBD code.
It it has been clear ever since. Iíll keep you posted if things change. Wish me luck!!!

Update since Oct? P0420 still gone?
 
  #33  
Old 12-08-2018, 06:07 AM
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It came back about 8 weeks later. I repeated the process and it went away again. As of today it is the light is still off and the car is running well. Except for the water pump, but that’s another story...
 
  #34  
Old 12-08-2018, 01:10 PM
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Originally Posted by xjagRI View Post
It came back about 8 weeks later. I repeated the process and it went away again. As of today it is the light is still off and the car is running well. Except for the water pump, but thatís another story...

I hope it stays off for you.. I did not get one on mine until a recent replacement of spark plugs and Coil packs.. after the mechanic put everything back together my P0301 Code was off and I suddenly got the P0420.. the car runs great though.. so I'm thinking that since it wasn't there before, the mechanic must not have installed the manifold back correctly or may have displaced the gaskets when reinstalling. It doesn't seem likely that my catalytic converter would suddenly fail from pulling the manifold off and putting it back on.. LOL ..

I haven't checked it yet, but I need to check the manifold bolts to make sure they're not loose.. Since 3 of the bolts are not the same length, I am crossing my fingers that the mechanic understood this and did not put them back in the wrong order.. of course when I ran the car back up there they were less than accommodating in trying to help resolve the problem.. they already have my money so "it wasn't them," despite having the intake manifold off (intake manifold leak being one of the reasons for a P0420).

Waterpump! If it's not one thing if it comes another right!?
 

Last edited by DavidDThornton; 12-08-2018 at 01:55 PM.
  #35  
Old 12-09-2018, 08:39 PM
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I think what is happening with the 0420 code is that the misfire caused by the bad coil/plug creates soot and pollution that coats the substrate in cat and prevents it from working effectively. The seafoam treatment seems to clean it, at least for a while. Fortunately for me, the substrate is is good condition. I was able to check it using an endoscope. Others on the forum haven’t been so lucky and the substrate was all broken.

The water pump pump is a relatively easy fix. If it wasn’t 12 F degrees here, I’d fix it myself. But, I’ll let my local guy do it. He’s got a heated shop. Parts on order...
 
  #36  
Old 12-10-2018, 07:14 AM
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Originally Posted by xjagRI View Post
I think what is happening with the 0420 code is that the misfire caused by the bad coil/plug creates soot and pollution that coats the substrate in cat and prevents it from working effectively.
From what I've read, the misfire causes incomplete detonation of the fuel which accumulates in the cat. It's causes the cat to get too hot in which is what damages the precious metals on the honeycombs inside the cat.. of course the longer this is allowed to continue while driving the car, it can actually cause sufficient damage to make the honeycomb crumble overtime.. and this will actually block the cat.. so you can have failure of the cat without any blockage, because the O2 sensors pick up that the cat is not doing it's job, which is what generates the P0420. Or you can get to the point to where the honeycomb fails and completely blocks.

Regarding the water pump.. smart move because the car doesn't always cooperate with problems during perfect weather.. mine didn't either.. lol..
 
  #37  
Old 01-08-2019, 09:52 PM
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Water pump was finally done before Christmas. That took care of the leak and an annoying burnt coolant smell in the cabin, but then I had a O2 sensor on Bank two light up. I think it was a casualty of the water pump work. A wire got pinched or something. New sensor and all lights are off for a few weeks now.
 
  #38  
Old 01-16-2019, 10:12 AM
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Originally Posted by DavidDThornton View Post
I hope it stays off for you.. I did not get one on mine until a recent replacement of spark plugs and Coil packs.. after the mechanic put everything back together my P0301 Code was off and I suddenly got the P0420.. the car runs great though.. so I'm thinking that since it wasn't there before, the mechanic must not have installed the manifold back correctly or may have displaced the gaskets when reinstalling. It doesn't seem likely that my catalytic converter would suddenly fail from pulling the manifold off and putting it back on.. LOL ..

I haven't checked it yet, but I need to check the manifold bolts to make sure they're not loose.. Since 3 of the bolts are not the same length, I am crossing my fingers that the mechanic understood this and did not put them back in the wrong order.. of course when I ran the car back up there they were less than accommodating in trying to help resolve the problem.. they already have my money so "it wasn't them," despite having the intake manifold off (intake manifold leak being one of the reasons for a P0420).

Waterpump! If it's not one thing if it comes another right!?
David Thornton I recently replaced the Intake manifold gaskets and spark plugs and IMT O rings, I am getting the P0420 as well. Did you resolve yours?
 
  #39  
Old 01-16-2019, 07:41 PM
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Originally Posted by BudL1te View Post
David Thornton I recently replaced the Intake manifold gaskets and spark plugs and IMT O rings, I am getting the P0420 as well. Did you resolve yours?
No the car is been running fine with great gas mileage so I decided to wait until it warms up in March.. I may go ahead and remove the manifold again and replace the upper gaskets again, and the lower gaskets.. because the code did not show up until after the tune up, I really don't think it's the catalytic converter..
 
 
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