# Is The Catalytic Converter Shot



## BigJim (Sep 2, 2008)

2002 Nissan Altima, running rough. Back ground on our daughter's car, some dude replaced the gasket on the valve cover and put some kind of sealant on the spark plug tubes to keep oil out of the tubes. The car ran great for three days. We went to see our grandson and her son graduate from Army Basic in Fort Jackson SC, which is 354 miles one way from here.

On the way back we got about 145 miles from home and she called and said she was broke down on the xway. We were about two miles behind her and carried them to a motel and came home to get some parts and drop off her other son and his girl friend.

Two of the plug tubes had a lot of oil in them fouling the plugs out, I replaced the valve cover because the tube seals were made into the cover and none replaceable. I also changed the plugs. After cleaning the plug wires/coils, the car didn't have a definite miss, just shaking badly and dies at idle when coming to a stop.

Her husband had drove the car with the gas petal on the floor for almost a 100 miles, so raw gas was pouring through the converter. Any ideas what all was ruined by him doing that?


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## 47_47 (Sep 11, 2007)

I'd pull the plugs again and check for tracking on the insulators. Spark will travel the path of least resistance. Secondary voltage is lowest at idle and maybe following a track. 

The cat(s) and oxygen sensors could be contaminated and shot, but you will generally have no power under acceleration or at higher speeds.


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## ktkelly (Apr 7, 2007)

Catalytic Convertor goes bad you will not only lose power, but you will also be able to smell it.


You would have a very heavy sulfur (rotten eggs). Can't miss it.


A sawzall to the exhaust pipe will work wonders if it's a welded in unit, simple unbolt if it a removable one, but you will have to replace it.


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## BigJim (Sep 2, 2008)

I just installed new plugs, so that shouldn't be a problem.

While it was running there was never a smell so maybe it is OK. I will try cleaning the throttle valve and plate and see if that helps.

Thanks for the help fellows.


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## Windows on Wash (Aug 30, 2011)

Good advice from ktkelly above.

When the converter fouls, you will actually be down on power and if you keep driving it like that, will ruin the motor. The down on power part is notable.


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## Brainbucket (Mar 30, 2015)

Install new plugs and wire/coil boots anytime there is oil intrusion. Now the cat. Yes you can ruin the cat by misfire and or excessive fuel. (and shock by getting hit and breaking up inside.) Get it running good without a misfire and then drive it on the interstate for a while. (30 min or so) In other words blow it out and let it heat up. You might get codes as you are doing this but that's ok. Just clear them then drive it normally. If a code comes back, record it and then clear. If the same code comes back then you gotta address it.:vs_cool:


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## BigJim (Sep 2, 2008)

Brainbucket said:


> Install new plugs and wire/coil boots anytime there is oil intrusion. Now the cat. Yes you can ruin the cat by misfire and or excessive fuel. (and shock by getting hit and breaking up inside.) Get it running good without a misfire and then drive it on the interstate for a while. (30 min or so) In other words blow it out and let it heat up. You might get codes as you are doing this but that's ok. Just clear them then drive it normally. If a code comes back, record it and then clear. If the same code comes back then you gotta address it.:vs_cool:


I really appreciate your information, I will give this a try and see what happens, I am slow but I will let you know how it goes.

I didn't know the boots on the coils could be replaced.


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## 47_47 (Sep 11, 2007)

@Brainbucket, where you affected by the recent LA rains?


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## BigJim (Sep 2, 2008)

I just cleaned the coil boots and and checked the plugs, the plugs are burning like they should be. All coils are hitting like they should. I changed out the PCV valve and changed out a vacuum line that was shot. I have not checked the EGR valve yet, too hot.

The car is running pretty smooth, just a little vibration. I drove around the block and when I accelerate, it bogs down a little but there is a loud hiss like something is leaking air. When I parked, I put my hand over the tail pipe, there was very little pressure, almost like the exhaust pipe was crushed. Anyone ever hear of anything like this?


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## Windows on Wash (Aug 30, 2011)

Keep and eye on the temp gauge when you are running that car. 

If the cat is blocked, she will heat up a good bit.


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## BigJim (Sep 2, 2008)

Windows on Wash said:


> Keep and eye on the temp gauge when you are running that car.
> 
> If the cat is blocked, she will heat up a good bit.


Thanks WoW, I will check that.


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## Bigplanz (Apr 10, 2009)

If you take the O2 sensor out (the one right before the Cat) and performance improves, that generally means the Cat is plugged up. Exhaust (a little) will go out the hole where the O2 sensor is located. Don't leave the sensor out any longer than to check if performance improves. All sorts of CEL codes will be triggered.


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## BigJim (Sep 2, 2008)

Bigplanz said:


> If you take the O2 sensor out (the one right before the Cat) and performance improves, that generally means the Cat is plugged up. Exhaust (a little) will go out the hole where the O2 sensor is located. Don't leave the sensor out any longer than to check if performance improves. All sorts of CEL codes will be triggered.


I appreciate the information Big, I went back out there today and realized that the muffler has two pipes for exhaust, I don't know how I over looked that but I did. I checked and it is blowing exhaust like it should. 

I checked the codes and there were 8, they had to do with random misfire, the converter but mostly the electronic throttle. Have any of you checked to see all you have to do to program one of those things, unbelievable.

Mechanics today have to be computer gurus and everything else. Not like when I was a mechanic back in the 60s, just a motor and trans to fool with back then, these new cars are unreal.


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## Mort (Nov 26, 2008)

I think it's easier now. You just plug a reader in and it tells you exactly what is wrong. I just did it not long ago, turns out it was the O2 sensor. No guess work.


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## BigJim (Sep 2, 2008)

Mort said:


> I think it's easier now. You just plug a reader in and it tells you exactly what is wrong. I just did it not long ago, turns out it was the O2 sensor. No guess work.


I wish this one was that easy, this car is running really rough and I think the hissing noise is coming from the electronic throttle unit. This throttle valve can not be cleaned because if you open the throttle manually it will mess it up, don't see how it could mess it up more but it says it will so I will leave it to the younger fellows to fix this one.


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## Windows on Wash (Aug 30, 2011)

A vacuum leak is still a vacuum leak. 

Search for that via normal diagnosis.


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## de-nagorg (Feb 23, 2014)

That throttle unit is likely a vacuum / electronic controlled device, once the vacuum seal is broken by someone opening it, it will not function properly. 

As you have been advised get a diagnostic device specific to this Nissan. 

Then go from there.


ED


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## BigJim (Sep 2, 2008)

Windows on Wash said:


> A vacuum leak is still a vacuum leak.
> 
> Search for that via normal diagnosis.


I did check for vacuum leaks and didn't find any, I may need to try again with a different method. I was using a plumbers propane torch to see if the engine sped up. I was a little gun shy using the torch, I was afraid of a spark that caused a flair up. I did the test quicker than I normally would have because of that. :smile:


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## Windows on Wash (Aug 30, 2011)

Regular carb spray will do it.


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## Brainbucket (Mar 30, 2015)

47_47 said:


> @*Brainbucket* , where you affected by the recent LA rains?


Yes. I was in the middle of it. I got water in my house but it was 6 inches. Most people lost everything. But I have flood insurance so I'm good. :vs_cool:
That hissing is probably a stopped up cat. The exhaust is not going where is needs to. Fix the cat first then see if any of those codes come back. Take it to a muffler shop and they can show you. I use to do carb spray until it caught on fire. Business stepped up quickly. Smoke it with a smoke machine.


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## BigJim (Sep 2, 2008)

Brainbucket said:


> Yes. I was in the middle of it. I got water in my house but it was 6 inches. Most people lost everything. But I have flood insurance so I'm good. :vs_cool:
> That hissing is probably a stopped up cat. The exhaust is not going where is needs to. Fix the cat first then see if any of those codes come back. Take it to a muffler shop and they can show you. I use to do carb spray until it caught on fire. Business stepped up quickly. Smoke it with a smoke machine.


Thanks BB I will have that checked out. 

I use to use starter fluid but that is a little scary also.


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## de-nagorg (Feb 23, 2014)

BigJim said:


> Thanks BB I will have that checked out.
> 
> I use to use starter fluid but that is a little scary also.



That and the ether HIGH, followed by the ether headache. :devil3:


ED


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## Brainbucket (Mar 30, 2015)

Here is a video of the flood in Walker, Louisiana. https://www.facebook.com/richard.cragg.14/videos/10154467681814853/ It's 55 min long. Wait for it.:vs_cool:


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