4.0 In need of exhaust advice

[chap9940]

Hello everyone and thanks for this great site it has a wealth of information and I do appreciate that.

Over the last couple of days my check engine light came on and I stopped by the local autozone and it checked out as being my bank 1 o2 reading too lean. So I assumed it was either a vacume leak, (I checked with ether and found nothing of intrest) but most likely a faulty o2 (125k no reason to belive they have ever been replaced. and upon removel I am 99% sure its the original...lol).......Anyways while removing the o2 I noticed it was ridiculously tight and it literally took me an hour wrenching it out and it fought me all the way. Well low and behold the o2 sensor decided to leave its threads in the bung and I spent another hour picking and trying to get the new one to start without any luck.....My exhaust is in need of replacing, I belive it to be leaking from the manifold to the y pipe gasket its had a slight tick to it...the welds from my muffler to tailpipe has shot its wad and upon inspection it looks like there is only one hanger holding the whole exhaust up anyways. (not the cause of the CEL code its been like this as long as I've owned it).

Cnsidering how I already buggered my factory Y pipe's bung up I figure it might be a sign that its time for me to just replace everything. Now here's my dilemma for which I need input.

I assume the exhaust shop can take a couple pieces of pipe fab up a replacement for the factory Y pipe. And tap it for my upstream o2 sensors. Now with regards to the Cats (I understand all legalities, with them and plan on not breaking any laws.....)....

Can I replace my factory cats with a single aftermarket cat and place the downstream o2 somewhere after it?

I am thinking about having a fabbed Y pipe and it feeds into a cheap aftermarket CAT and having a single pipe feeding into a single in / dual out muffler (since Im replacing everything I might as well try and make it pretty) lol....

I will post a couple of simple drawings of what I was thinking about doing (and I do mean like kindergarden simple) of what I am talking about and if anyone would care to comment and please advise me what I should do best (Im looking for cheap, functional, and no CEL codes)

Thanks, and I appreciate everything

 

[chap9940]

As with regards to pipe what size pipe should I use? 2 1/4 or 2 1/2.....Does anyone know a good distance from the cat should the downstream o2 be from an aftermarket cat? I assume it should be the same distance as it currently is stock but I didnt know if someone may have had a bad/good experience doing the same with an aftermarket cat....Im just trying to avoid and more CEL codes (its my OCD)....lol...

thanks

 

[chap9940]

Im also open to recommendations of brands for the cat and muffler as to what anyone may know to work well together and sound decent enough...I will probably buy this stuff from ebay / jegs / summit...etc instead of from the exhaust shop due to the fact they charge a hefty markup and they are already gonna make money off me...lol...Thanks

 

[Original_Ranger84]

The idea seems pretty good. I think however you could pickup a factory Y pipe from the junkyard, that way it would fit and be just right. I don't see a problem otherwise except you might need to add 2 cat, because the 1 cat might not be efficent enough and cause the downstream cat to throw a code. I think you can pick up a magnaflow highflow factory cat setup. It should have the factory 2 cats and proper hook ups. For the pipe I would use 2.25 because its bigger but definately not too big because 2.5" is pushing it... For mufflers just look on youtube. find what you like and get it. Like I like my dynomax while most people think its too quiet I think its just right.

 

[RangerFabWorks]

autozone sells a spark plug thread chaser thats perfect for o2 sensors.

ive done that 3 times already. that tool and a little grease makes your life so much easier.

 

[RangerFabWorks]

http://www.autozone.com/autozone/ca...+plug+hole+thread+chaser&brandName=Great+Neck

http://www.autozone.com/autozone/ca...gen+sensor+thread+chaser&brandName=Great+Neck

 

[AllanD]

Oxygen sensors use the same 18mm threads as old ford engine
spark plugs.

So the thread chaser for 18mm thread spark plugs will clean
out the threads.

In addition if the threads are beyond simply "chasing" with one
of those tools the save-a-thread solid inserts will do the job.

And the welded in place bung for the Oxygen sensor has more
than enough "meat" to it to allow for installing a threaded insert.

AD

 

[chap9940]

Yeah the thread chaser was my last hope lol...since its sunday and i couldnt get any work done at a shop today I went ahead and picked one up and it took about an hour of finageling but I got it to finally get a bite and I was able to clean the threads.....so with that said no more check engine light, all is well and I am happy thus far. With regards to the exhaust work I am probably gonna take it to the shop on tuesday cause it does need a muffler and some hangers repaired....I think Im gonna order a Single in /Single out cherry bomb extreme muffler, by doing so I get a cheap replacement muffler and can reuse my old pipes, so I will just be out the expense of having the new one welded back in place....lol I know its probably gonna be loud, but the truck is already loud I will just be going to a less sloppy loud hopefully cause Im gonna keep stock pipes / cats.....my only concern with that is the only one I can find on jegs is a 2.5 in and 2.5 out but I guess the shop can make it all fit nice....lol.... I'll be sure to post a before and after video on youtube after its all done so I guess time will tell...lol...Thanks

 

[Yellowsplash]

Before blaming the O2 sensor for being faulty, you instead should fit the exhaust leak BEFORE the O2 sensor that is causing it to read erroneous readings.

btw, there is no gasket between the manifold and y-pipe....its a ball flange. You need to tighten it up to fix the leak. If its corroded (very likely), you may need to replace the studs to get it tightened back up.

 

[chap9940]

Muffler replaced, I went with a 26 inch glasspack. Sounds fine, maybe a little more rumble than stock..will get a sound clip up as soon as the weather permits