Badiceman Posted April 6, 2008 Share Posted April 6, 2008 My Cat went to hell all clogged up and I removed it. I don’t really want to put on a new one due to the fact I have no money and there are not any emissions tests where I live. So I want to just throw a glass pack muffler on there and call it good. But wtf do I do with the o2 sensor? I understand what it does but I have really no idea how it affects pathfinders. Mine is an '88 that runs like @!*%. And speaking of running like @!*%. Before I removed the exhaust it ran bad but my auto teacher sprayed carb cleaner into the intake which made it idle good for a sec. He said it’s running really lean. What might cause that? All ideas are very appreciated! Link to comment Share on other sites More sharing options...
unccpathfinder Posted April 6, 2008 Share Posted April 6, 2008 if you dont have the O2 then it will run either lean or rich...depending on where he spayed the cleaner it could affect the MAF and it may need to be cleaned Link to comment Share on other sites More sharing options...
crazyhayseed Posted April 6, 2008 Share Posted April 6, 2008 I thought the O2 was before the cat, mounted to the intermediate pipe... Is the 88 diferent from my 95? How much of the exhaust did you remove? Link to comment Share on other sites More sharing options...
MY1PATH Posted April 6, 2008 Share Posted April 6, 2008 I thought the O2 was before the cat, mounted to the intermediate pipe... Is the 88 diferent from my 95? How much of the exhaust did you remove? your right crazyhayseed its before the cat. so removing the cat shouldnt effect it. correct me if I'm wrong but I thought these engines mixed fuel based only on the MAF feedback until 2800 rpm and then mix based only on O2 sensor feedback above 2800 rpm. I do know that opening your exhaust too much can also cause problems, I played arround with a few configurations after putting on my headers; Open header took away almost all my power uness I ran it near redline and it had it had an lopey Idle sound like an agressively cammed v8 Open cat (2.25 inch cat) gave me power in the high rpm range but no low end compared to stock and still a wavy idle I put a mufler on the end of that to quiet it a litte (2.5 magnaflow, flows like a cherry bomb but differant sound) and my Idle steadied out and my low end torqe came back. I talked to some guys who dyno tune exhaust systems and for lower end power and a flatter torqe band(good thing for 4x4) you don't want to open it up too much and you want a few feet of pipe after your Y pipe for the gasses to travel thru before comming out of the vehicle. In shorter words a 2" 2.25" glass pack for a cat should work, plenty of people do it. Link to comment Share on other sites More sharing options...
crazyhayseed Posted April 6, 2008 Share Posted April 6, 2008 (edited) Open header took away almost all my power uness I ran it near redline That's back pressure... or lack of. Back pressure has to be balanced to the motor. Too much or too little can both create power loss or cause damage to your engine. It's the reason you don't run w/o manifolds or stick sh*t in your tail pipe. You don't hear much about that with trucks, 'cause, well, they're trucks... Who cares? It sounds cool! But you get beat with the concept on a daily basis when tuning sports cars. Try shopping for an exhaust system for a 240sx some time. (Don't ask me to get much more technical than that BTW... You'll need a guru for the rest. Try one of M. Kojima's articles.) Edited April 6, 2008 by crazyhayseed Link to comment Share on other sites More sharing options...
Badiceman Posted April 7, 2008 Author Share Posted April 7, 2008 I removed the cat and everything back from it. Link to comment Share on other sites More sharing options...
crazyhayseed Posted April 7, 2008 Share Posted April 7, 2008 (edited) I'm having a hard time putting this pic into perspective... The intermediate is gone isn't it? Why don't you just gut the cat and bolt everything back in? I don't think you're helping your motor much by running it the way you are ATM. Here's a diagram of the exhaust system. The part in yellow is the intermediate pipe that the O2 mounts to. Edited April 7, 2008 by crazyhayseed Link to comment Share on other sites More sharing options...
LandShark Posted April 7, 2008 Share Posted April 7, 2008 Just got a copy of Off-Road Adventures(4Wheel Parts Magazine) in the mail today, and was just skimming through it briefly. There's a pretty good article about exhaust. Talks about how no exhaust system is just as bad as a restricted system, due to an effect called Scavenging. I'd link it, but seems like the latest issue they have on the website is Jan' 08. Off-Road Adventures If you want me to type out some of this article on scavenging let me know. Link to comment Share on other sites More sharing options...
Badiceman Posted April 7, 2008 Author Share Posted April 7, 2008 Nope the intermediate pipe is still there. All I did was unbolt the cat and everything behind it. Link to comment Share on other sites More sharing options...
MY1PATH Posted April 7, 2008 Share Posted April 7, 2008 Nope the intermediate pipe is still there. All I did was unbolt the cat and everything behind it. If the cat has a long pipe sticing out of it with a hole for the o2 sensor look closer the bolts for that pipe may be hidden by the heat sheild and bam you have a mid pipe and a cat. if not then the mid pipe is still on the truck. Link to comment Share on other sites More sharing options...
Badiceman Posted April 7, 2008 Author Share Posted April 7, 2008 Yeah I found the bolts behind the heat sheild. Just the cat is off. Link to comment Share on other sites More sharing options...
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