bank 1 precat remove / install

A forum for the Nissan Quest... minivan lovers unite!
dburckhardt
Posts: 5
Joined: Sat Oct 15, 2016 10:59 pm

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2005 nissan quest s 4 spd

Has anyone removed and replaced the bank 1 precat? The bank 1 precat is located nearest the firewall and is positioned vertically, connecting to the exhaust manifold and the front exhaust tube. The service manual indicates the suspension member requires removal, along with the engine cowl, wheels, front and rear primary motor mount bolt, suspension of the engine using a commercial tool, removal of front exhaust (actually the exhaust behind the precat), disconnect right connecting rod and stabilizer bar bushings, remove power steering line bracket, remove mounting bolts on lower side of steering gear, ect....

I removed the rusted bolts and bracket from the bottom end of the precat and loosened the 2 bolts that connect the top of the precat to the exhaust manifold. There are 2 studs that extend from the top of the exhaust manifold into the top of the precat and are secured by a nut on the top of the exhaust manifold. Those 2 studs are not accessible from the engine bay or from the under the engine. The exhaust manifold heat shield has 3 10 mm bolts and that heat shield covers the 2 studs from below.

Again, has anyone removed and replaced the bank 1 precat without removing the suspension member?


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centralcoaster33
Posts: 2769
Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

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I have read that these are terrible to work on just because of situations like you mention above. I do not know a shortcut, but this reply will bump your post up the list in case someone else can see it and help. If I truly hated my vehicle, I'd be tempted to drill a hole through the floor and access the bolts, then plug the hole. Maybe you can loosen and lower the steering member a little bit? Or just go through all of the steps, get it done and get an alignment, hope you never have to replace the sensor again. Good luck!

dburckhardt
Posts: 5
Joined: Sat Oct 15, 2016 10:59 pm

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I figured out a way to remove / install the bank 1 precat. My method did NOT follow most of steps outlined in the nissan shop manual.

The reason for replacing the bank 1 precat was the p0420 code, which I had seen on my nissan quest, 20 times in the last 4 years. Each time I cleared the code. After reading many opinions regarding the p0420 code, I concluded, although I may be wrong, that the precat was the cause of the p0420 and it had to be replaced to eliminate the code. So, purchased a direct fit catalytic converter manufactured by Walker.

The original nissan precat was missing the catalyst material, if looking in the downstream end near the opening for the o2 sensor. If looking into the upstream end that connects to the exhaust manifold, the catalyst material was black but still intact, and the material I could see was NOT missing any material. I assume there was not enough catalyst material for the exhaust system sensors and would trip the p0420 code.

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centralcoaster33
Posts: 2769
Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

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So, it's fixed? No messing with the steering?

dburckhardt
Posts: 5
Joined: Sat Oct 15, 2016 10:59 pm

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The precat is fixed and no more p0420 codes. It's been 3 months since the repair. As far messing with the steering goes; removed the passenger wheel, lower control arm, stabilizer connecting rod and drained the power steering fluid. Removing those parts enabled me enough space to remove precat. Even with the additional space it was difficult to remove and replace, but it was successful and so far no problems.

far raf
Posts: 213
Joined: Tue Feb 21, 2017 2:53 pm
Car: 2005 Nissan Quest SE (standard? simple? edition - i.e. nothing special)

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Mine throws that code as well, but I am not going to do any repairs and will get a conditional pass next year. It is simply not worth it, as the repairs are like 3x the amount required to get a conditional pass where I live.

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centralcoaster33
Posts: 2769
Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

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Glad you got your precat replaced.

mushman
Posts: 2
Joined: Mon Aug 07, 2017 7:01 pm
Car: 05 Nissan Quest

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Where did you purchase the replacement cat from?
My 05 came home on a tow truck tonight I have been ignoring the code for a year, no power I am guessing clogged cat. I will diagnose more tomorrow.

dburckhardt
Posts: 5
Joined: Sat Oct 15, 2016 10:59 pm

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Advance Auto Parts
below is the web link to the part on advanc auto website.
https://shop.advanceautoparts.com/p/wal ... +converter

Walker EPA Ultra Direct Fit Converter; part # 16438

cleeland
Posts: 12
Joined: Fri Mar 05, 2004 6:31 pm
Car: Competitive Cycling

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I realize this is an old post, but I'm really interested in knowing what your method was to remove/install pre-cat bank 1. I am looking at having to do that if I cannot get an estimate-based waiver this year.

cleeland
Posts: 12
Joined: Fri Mar 05, 2004 6:31 pm
Car: Competitive Cycling

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I haven't heard anything back from my inquiry about the technique, so I've started the process myself. I also have a P0328, which "knock sensor high", so I'm tearing down the top of the engine far enough to replace the knock sensor, i.e. remove all the intake. I did leave the throttle body in situ because it has the coolant lines running to it, and I really didn't want to drain coolant from the block. If it gets in the way I'll go buy another pinch clamp so I only lose a little.

The general strategy that doesn't involve dropping the suspension member is:
  • remove upper intake at least as far as you would to get to the rear bank of plugs
  • remove the heat shield for the catalytic converter to gain access to the two nuts closest to the firewall
  • remove all the nuts and bolts related to the cat and lower it out of the way
Sounds so simple until you realize that the space btw. the engine and the firewall is really tight and the angles of some of those fasteners is angled making using a ratchet and extension tough. I have small hands for a male and can barely reach my hands back there. I may have to get my wife to crawl across the top of the engine and shove her hands down in there.

It appears that removing the heat shield, or at least moving it out of the way enough to get access to the bolts may require removal of the A/F sensor in the exhaust manifold and/or the power steering pressure line that arches up and over btw the engine and the firewall.

chefnee
Posts: 17
Joined: Tue Jul 05, 2016 9:57 am
Car: 2008 Nissan Quest SE
Location: Tennessee, USA

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I had the same issue for my 2008 SE. I was able to only replace bank 2 up and downstream and bank 1 down stream. I'm assuming the one in question is behind the intake manifold. I had a hard time getting it out. I ended up cutting the wiring and stripping it. My uncle had to remove the wipers, cowl, and then the intake manifold to finally be able to see this part.

Did anyone have difficulty with aftermarket parts? I ended up having to having to bite the bullet and buy OEM O2 sensors. My blue beauty only has expensive taste! After completing all 4 O2 sensors, resetting the codes, and driving 50~100 miles the codes DID NOT appear anymore.


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