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Sedans Nissan Altima Nissan Altima Engine Failures
498 messages, Last post on Nov 23, 2009 at 6:40 PM
You are in the Nissan Altima Forum. Your Hosts are pat & karens
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I have a 05 Altima with the 2.5 engine, 31,500 miles, which I bought used about 6 weeks ago and have put 1200 mile on. Last week the SES light came on and I had Autozone pull the code. The infamous P0-420. Yesterday I had a dealer check it out and they found the pre-cat was "coming apart internally" and replaced it under warranty. Hopefully, none or very little material made it into the engine; I'll be keeping watch for oil consumption and hope that any problem with that shows in the next 30K or 2 years while the drive train warranty is in effect. So, either the pre-cat was just a bad part or the '02-'03 recall situation will be continuing as all 2.5 reach higher mileage. Anyone know if or what changes were made for the 04-06's at address the failure of the pre-cat? I'm thinking none other the the ECM re-programming to maybe lean out the engine. Chris
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Replying to: ckeough (May 21, 2008 6:39 am) that's all it really needs. the cat wont deteriorate without gas igniting in there. The problem isn't a faulty cat, or a faulty engine. its unburned gas burning in the cat and tearing it apart. You took your car in as soon as that light came on, a very smart man. unfortunately, most people dont. most people figure they left the gas cap too loose or something, and don't want to spend the $80-100 to get the code reset. |
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Hi all, I am new on this forum and hopefully someone can help me out. I am replacing my intake manifold gasket and have run into some kinks. I am using the Haynes manual as reference for my install. Do I have to take the head & timing chain off to get to the intake manifold? The manual did not make mention of the timing chain so I am at a loss. I am trying to separate the plenum from the head to get to it. Can this be done. Please advise.
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Replying to: kynymac (May 27, 2008 10:26 am) First, unbolt the upper manifold and Plenum (all one piece). Second, unbolt the lower intake manifold from the back of the engine. There is a bracket under the lower intake that has to be removed. To see all the pictures of how to take it apart and put it together, look at the links in messege #182. See Teardown Photos #DSC06971 through DSC06980, and see Rebuild Photos #DSC07265 through DSC07270. Good luck, E.D. in Sunny Florida |
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Replying to: pdupuy (May 02, 2008 6:20 am)
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Replying to: puds2002 (Jun 12, 2008 11:47 am)
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Replying to: smoothride4me (Jun 12, 2008 3:03 pm) |
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Replying to: electricdesign (Jan 31, 2008 7:12 pm) My question is since the emission is not checked where I live is it better to remove the CAT? Thanks Onuchukwu Chuma.ndiboy  yahoo.com 2348033974181. |
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Replying to: electricdesign (Jan 19, 2008 9:33 pm) I was expecting to see this cat stuff in one bit, but to no avail.One thing that is not clear to me is the whitish brown material in the container.Is it the stuff that is blocking the exhaust? Then there is another hole there, probably after the plug was removed, please I need more clarification now that I have seen the pics. The pre cat, I must confess i didnt see it.I tried looking into the manifold when it was lowered but i couldnt identify anything I could call the cat.I thought the cat will be something big that I will easily see. I need these things to be clear because I will like to remove the one in my Altima 2002 car,especially the pre cat,early before any problem starts.Mine is around 76,000miles now. ED,I need early and fast response,thanks and God bless you.I want mine to run like your daudhters car!!!!!! I love the car,stay in Nigeria, so if the car develops a problem,it gonna be terrible. Chuma.
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Replying to: ndiboy (Jul 25, 2008 1:31 pm) I'll be glad to help clear things up. Yes, you have a good Idea to remove the pre cat before the problems start, especially since you don't have emissions inspections. The best way to refer to the pictures is by NUMBERS, since there are about 700 pictures or more. The pre cat is built into the exhaust manifold. The top of the exhaust manifold, as it is being removed, is shown in teardown picture DSC06900. The bottom of the exhaust manifold is shown in teardown pictures DSC06930 through DSC06934, it shows views looking up inside the bottom of the exhaust manifold. Normally you would see the precat there, but in those pictures it is gone, the exhaust manifold is EMPTY. If the precat was there, you would see a screen in the bottom that holds the precat material above it. In this case the screen failed and the screen and all the precat material got blown out of the exhaust manifold and was blown down the exhaust pipe into the SECOND cat. When the material got blown down to the SECOND cat, it plugged up the second cat. That is when I had to remove and unplug the second cat. And yes, that brown and whitish material IS the contents of the SECOND cat plus the contents of pre cat. What happened now is that both cats are hollowed out, the pre cat and the second cat, giving a wide open exhaust, of course it still goes through the muffler, like a regular exhaust. Looking at the unplug cat photos, photos DSC06096 & DSC06097 show the old cat material that was removed from the second cat. This contains the material from the pre cat (first cat) and second cat. Then photos DSC06098 through DSC06100 show the hollowed out inside of the second cat after the contents have been removed. Photo DSC06087 shows the inside of the second cat BEFORE the contents were removed, the cat is plugged in this picture. What you see is the screen that holds the cat material in place, but the material had got wet and compacted, and the exhaust gas could not flow through it. The cat normally works by allowing the exhaust gas to pass through the cat material and then through the screen and then on to the muffler. The purpose of the screen is to hold the cat material in place. Once ithe cat pluggs up, it's no good anymore unless you unplug it or replace it. Unplugging the second was fairly easy once I had it off the car, just use a hammer and a metal punch or small diameter piece of pipe to hammer the stuff out. If you look into the bottom of the pre cat, you should see a screen just like in photo DSC 06087, unless the material has already blown out. You could clean out the pre cat the same way, break the screen and material out with a piece of small diameter pipe and a hammer. I think you should be able to hollow out the pre cat from under the car by removing the exhaust pipe and breaking out the material through the bottom opening, but be careful to not damage the oxygen sensors. It is best to remove the second oxygen sensor before you attempt to break the material out of the pre cat. You can run the engine for just a few seconds to blow the loose material out of the precat. After the pre cat is hollowed out, the service engine soon light will come on shortly thereafter, because the SECOND oxygen sensor will read the SAME as the FIRST oxygen sensor. To avoid this, you will need to add the O2 cheater at the SECOND oxygen sensor to make it read differently and for the light to stay off. Hope this helps, Good Luck, E.D. in Sunny Florida USA
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