Xterra Catalytic Converter needs replacing? - Nissan Forum
Truck & SUV Armada, Frontier, Murano, Pathfinder, Quest, Titan, X-Trail, Xterra

 
LinkBack Thread Tools Display Modes
#1 Old Oct 19th, 2010, 10:16 AM
NissanForums Newbie
 
Join Date: Oct 2010
Posts: 3
Xterra Catalytic Converter needs replacing?

Last spring I bought an 02 Xterra SE supercharged. I love this vehicle when it is running properly but have been barely able to drive it since buying it because of a cascade of issues. Most of these have been repaired and it seems to run well but now I have a service engine light that is apparently coding to the catalytic converter and I am tired to putting money into the truck and want people's opinions on what is my best option. Let me go back in the history of the truck because I think it will be important in explaining the current problem. Keep in mind I have limited do-it-yourself knowledge but try whenever I think I can.

I bought the Xterra used with about 120,000 km on it (about 75,000 miles). Shortly after buying it, it started to idle rough and the service engine light came on. The nissan dealership coded it and said that it was a fuel problem and showed us how filthy the fuel filter was. We changed that and were told that if the problem came up again, it would likely be the fuel pump dying because of the clogged fuel filter. Shortly after having the service engine light cleared, it came back on and we suspected the fuel pump, which in fact seems to be ok. Instead of that, it coded as a single cylinder misfire. We tried flushing the fuel rail and that seemed to help for a few 100 km but the problem came back so after some investigation, we had the #4 injector rebuilt. Turns out that the injector was seeping fuel and flooding the #4 cylinder, and all of this makes sense to me. About 1000 km after that the service engine light came back on. This time it coded as the catalytic converter (I don't have the exact code unfortunately). The dealership said it was maybe just some bad gas or a residual from the previous problem and that we could try clearing the light and see if it came back. Right after that, I moved about 600 km and a few days after arriving, the light came back on. I assume that this is the catalytic converter again, but don't have a good shop that I trust yet and haven't taken it in to get checked. Keep in mind, the whole time that this light has been on, the Xterra has not been idling rough or anything like it was before when it was misfiring. The only thing it does, is suck down gas, but I think this is pretty much expected for the supercharged model.

From what I have read on these forums, everything makes sense and a cylinder misfire could cause the catalytic converter to fail. What I do not know is if the catalytic converter will continue to get worse until it gets completely plugged, even if I have solved the underlying cause and my question is, what should I do now? I see a few options.

1. I could keep running it with the service engine light on, hoping that the cat is just running below efficiency.

2. I live in Alberta where there is no emissions testing, so I could just remove both catalytic converters and put in a straight pipe.

3. Try to find a good muffler shop to put in an after-market cat so that I don't have to pay the high prices of the dealership.

4. Suck it up and go with genuine nissan parts and hope that putting the extra money in will fix everything once and for all.

As far as I understand from previous research, options 1-3 will not clear the service engine light, but I think I can live with that if I'm not going to do more damage in the long run.

Any advice?
Xterradriver is offline  
Sponsored Links
Advertisement
 
#2 Old Oct 19th, 2010, 11:27 AM
Sorta-Newbie
 
MichaelH's Avatar
 
Join Date: Oct 2010
Location: Georgia
Posts: 13
Depending on the code you have, P0420 or P0430 right or left bank. Several things can cause this problem, intake leaks, injector, injector leaks, improper ignition timing, or the catalyst itself. I would recommend taking it to a Nissan dealer and biting the bullet to have it properlly diagnosed and repaired by a professional. I dont know about Alberta dealers, But here if we diagnose something and repair it we have to stand behind our repairs. I have replaced a few catalysts on Xterra's for this problem. Anytime the catalyst gets to much fuel there is usally damage to the convertor. Also a ctalyst can start too break apart and particles can end up in the cylinders of the engine. Hope that helps.
#3 Old Oct 19th, 2010, 01:27 PM
NF Mod
 
smj999smj's Avatar
 
Join Date: Jan 2006
Location: Prospect, VA
Posts: 6,118
You're best bet would be to replace the catalytic converter with an OEM part, in my opinion, assuming there aren't any current conditions (ie exhaust leaks) that would cause the code to set. I've seen some poor quality aftermarket catalytic converters installed that end up having the catalytic efficiency code set anyway. If it is just an efficiency issue, which could be checked by monitoring the upstream and downstream O2 sensors with a scantool, no further damage will result but, as you stated, you will have the check engine light on at all times. The problem is that if another problem arises that would turn on the check engine light, you won't know because the light will already be on for the failed catalytic converter. As far as the catalyst breaking up and getting sucked into the engine, that's typically only an issue where the engine uses variable valve timing in place of an EGR valve to recirculate exhaust gases, such as on the L31 Altimas with the QR25DE engine. But, a catalyst that is restrictive can result in poor gas mileage and drivability issues and even a potential fire hazard if it starts to overheat excessively.
#4 Old Oct 20th, 2010, 09:26 AM
NissanForums Newbie
 
Join Date: Oct 2010
Posts: 3
Ok, I'm thinking I'll do whatever it takes to clear the service engine light cause I dont want to miss a big issue later in life. Bite the bullet as it were and get it running properly. I've had a few suggestions from the old dealership as well as a friend who is an apprentice mechanic though and would appreciate your takes on them. The old dealership said they could run a back pressure test to see if the cat is the problem. Will that give a similar result as monitoring the O2 sensors? Will it give me a definitive answer? Will it be costly? My apprentice friend said we could change all of the O2 sensors first as it may be cheaper and could be a possible fix. Is it worth trying this, knowing the cylinder misfire history of the Xterra? Should these be changed at the same time even if the cat is the problem? My last question is, I've read that some of the nissans have updated software for the ecs (I think??) that could clear the problem. Is this applicable to an '02 Xterra and is this worth checking into?

Thanks again for the help guys, its much appreciated.
Xterradriver is offline  
#5 Old Oct 20th, 2010, 01:25 PM
NF Mod
 
smj999smj's Avatar
 
Join Date: Jan 2006
Location: Prospect, VA
Posts: 6,118
A backpressure test is a good test for finding a restricted or clogged exhaust system, including catalytic converter. The O2 sensor located before the catalyst is removed and a fitting installed with a vacuum hose routed to a gauge. If the catalyst is restrictive or clogged, this test will pick it up easily. However, if the catalyst is not restrictive but has become inefficient, the only way to test the catalyst is by road testing the vehicle and monitoring the upstream and downstream O2 sensors. If the catalyst is breaking down the emissions as it should, one will see an approximate ratio of two upstream sensor rich to lean cycles for every one at the downstream sensor. A ratio of approx. 1:1 means the catalyst is not doing its job and will thow the P0420/P0430 catalyst efficiency codes.

As far as replacing all of the O2 sensors, I don't recommend it. I don't believe in replacing parts that have not been proved faulty unless all other means have been exhausted. This practice is costly to the customer and often a sign that the person working on the vehicle does not know how to diagnose a problem correctly. Also, if you used genuine Nissan sensors and going by the MSRP for them, that would equate to $717(not including labor) for the set of sensors! Each front is $170 and each rear is $188. Also, while it's possible to have a faulty O2 sensor not throw an O2 sensor code, it is rare and to have four faulty O2 sensors and not a single stored trouble code is extremely unlikely! A resistance check of each sensor can also be performed, but that doesn't necessarily mean the sensor is working properly, either. The O2 sensor operation can be seen by monitoring it with a scan tool.

There were some ECM software updates for R50 Pathfinders with the 3.5L that threw P0420/430 DTC's. These were one of the early Nissan ECM's that were programable and Nissan set the paramater limits on the oxygen sensors a bit on the tight side initially. The updated software expanded those limits. There was a software update on the '02 Xterra & Frontier w/ the supercharged engine but not for that reason; it was for cases of severly limited engine speed and possible MIL illumination. It was part of a voluntary recall campaign #R2013. Your Nissan dealer can use your VIN# to tell you if this campaign was performed on your vehicle.

As far as what the dealer will charge you for testing, I cannot say. You'll have to get a quote from them. I can tell you that the backpressure test takes about 20 minutes and is performed with the vehicle "cold." If the exhaust is too hot, it will melt the vacuum hose. As far as the time required to road test and monitor the O2 sensor cycling, approx. a half hour or so, maybe a little more, depending on the roads and traffic conditions near the dealer.

Last edited by smj999smj; Oct 20th, 2010 at 01:30 PM.
#6 Old Oct 29th, 2010, 11:11 AM
NissanForums Newbie
 
Join Date: Oct 2010
Posts: 3
Ok, a little update here. I took the Xterra into a nissan dealer and had them check the code. It was a P0430, which was not surprising. (I didnt want to tell them the history of the vehicle at this point because we had trouble at another dealership assuming that they knew the problem based on previous things and not actually investigating). They recommended changing out both catalytic converters. At first I thought that this was excessive since only one side had coded but after talking to both my friend and the old dealership and my father-in-law, they all suggested to just do both at the same time. Nissan prioritied the parts in and had the work done the next day. And I'm glad I decided to do it the right way, because they said that both cats were cracked. And they threw in a discount, which is nice. Overall, aside from the fact that it is an expensive repair, everything went very smoothly and I'm glad I did what I did. Thanks for the advice guys!
Xterradriver is offline  
#7 Old Nov 6th, 2010, 04:23 AM
NissanForums Newbie
 
Join Date: Nov 2010
Posts: 6
Quote:
Originally Posted by MichaelH View Post
Depending on the code you have, P0420 or P0430 right or left bank. Several things can cause this problem, intake leaks, injector, injector leaks, improper ignition timing, or the catalyst itself. I would recommend taking it to a Nissan dealer and biting the bullet to have it properlly diagnosed and repaired by a professional. I dont know about Alberta dealers, But here if we diagnose something and repair it we have to stand behind our repairs. I have replaced a few catalysts on Xterra's for this problem. Anytime the catalyst gets to much fuel there is usally damage to the convertor. Also a ctalyst can start too break apart and particles can end up in the cylinders of the engine. Hope that helps.
This would be help. This information is absolutely correct.
playtimeover is offline  
Reply

  Nissan Forum > Truck & SUV

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Nissan Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On