The Nissan Path

Hey all,

Its been a fast summer, and I've been so busy I haven't been spending much time here at the forum.

2005 Pathfinder, just clocked 360000km (224000mi). It needs an exhaust. I think I've settled on the standard walker replacement, though I've had some thoughts on the Bosal kit that is out there, as it looks a little more sturdy, and is actually a few bucks less in cost. All in, it will cost about $350 canadian to get the required exhaust parts, clamps and seals. Not too shabby!

However, I've been driving around with the P0420/P0430 code (Catalyst efficiency error) for probably about the last 10 years or so. No joke! If I reset the CEL while driving down the highway, it does not come back, until I start driving in town or starting and stopping. Then it comes back on right away.

I did my Fuel/air sensors about 5 years ago, replaced with Denso. I'm thinking they should be done again.

I also noticed that my Short Term Fuel Trim is sitting around 10-15% while driving at highway speeds.

I found a place here in Canada that sells replacement Catalytic converters for about $100 each. Here's what I was thinking:

1. Replace exhaust system. $350
2. Replace Front Catalytic Converters (premierautoexhaust.com) - $200
3. Knock a hole through the catalyst on the rear catalytic converters. They are not monitored anyways.
4. Replace all 4 O2/FA Sensors (either Denso or NGK) - $400
5. Replace MAF Sensor (Hitachi) - $80
6. Replace Spark Plugs (NGK 96355) - $50

After all this, I figure I'd be good for another 400k. For about $1100 canadian.

The only thing I figure I'm ignoring is Fuel Injectors... not sure if they should be done if there is no code associated with them.

Thoughts?

t

Fuel injectors are usually not an issue on these engines. If you are going to pull the plenum, then you could check them with an ohmmeter and compare to the factory service manual specs. Be aware that the rear sensors do not affect engine performance; they are only for ECM monitoring of the upstream converters...and it's "NTK" when it comes to sensors, not "NGK," which is the spark plug and ignition component division of the company. Both them and Denso are good choices.

Be prepared that aftermarket exhaust systems usually don't sound the same as the factory parts; they tend to be a little louder or a little courser sounding. Walker is good, but I find Bosal exhaust parts tend to be a little better. As far as the rear converters, it would probably be better to cut them open and gut them and weld them back together than just trying to punch the converter substrate out (a.k.a. "rodding"). If you don't get it all out, it will rattle or worse: get into the muffler or clog the exhaust. A custom exhaust shop could cut the converter part off of the assembly and replace it with straight pipe and a new flange and it shouldn't cost too much. I ended up going with Doug Thorley mid-pipes on my 2006, but that's a more expensive option.

The catalyst efficiency codes are likely due to inefficient converter substrate. I had P0430 codes trigger on both my 06 and 08 and fixed them both by installing O2 sensor spacers on the left bank, rear oxygen sensors. I got KKmoon stainless steel lambda sensor extenders M18 from Amazon.com for $6.59 each. Now I think they are around $11 each (free shipping), but still cheaper than a new converter! I checked out the converter site you linked. The prices are pretty cheap compared to other aftermarket converters, which has me concerned. Sometimes inexpensive converters don't use as much platinum or rhodium (or whatever precious metal they use in their substrate) than the factory parts or even reputable manufacturers like Walker and people sometimes find they still have CEL issues after they replace them with the cheaper parts...which is something they actually mention on their site. I also don't see any warranty info at their site. I believe Walker's warranty is for 5-years, IIRC? If you use them, let us know how you make out!

Any update ?

I changed out the exhaust with Walker parts. Bosal seems to no longer be available.

I haven't bothered with any of the sensors yet. I have put it on the list, but the thing runs so darn good and is so quiet now, I am remiss to screw with it!

Didn't bother with the cats at all, and in fact while doing the exhaust I was able to inspect the secondary cats and they looked super clean. So I left them alone!

I've been so toying with changing my exhaust but, it just doesn't need it yet. Just clicked over 128000 mi (205K) km. I'd love a slightly more louder exhaust just, because I love listening to exhaust sounds but, I really don't want something droney. Love to do it myself too instead of paying a muffler shop to install it.
See what's out there when the time comes.

Really want to make this wonderful machine last!