First, Like to say hi. New here. I've lerked a few times in the past. Had my 2002 F150 5.4l SuperCrew 4X4 FX for 1/2 a year it has 130k on it.

Had it in for service the beginning of summer and was told that there was noise coming from one of the converters (Passenger side) and the innards where loose. Given an extimate on a couple of diffrent options to get it replaced in the near future. Took the truck on a trip and the sensors where causing the engine light to come on.

To save some money I decided to tackle the job myself. I plan on picking up an aftermarket bolt on, but first I wanted to make sure I could do it myself. Today I tried tackling the job of taking it off. I got all the bolts off except been having trouble with the sensor by the exhaust manifold (1st). Any tricks on getting that off? Been using an open end wrench.

Also, for me to get the Passenger cat off, do I need to remove any of the exhaust or driver side cat?

Any suggestions on a aftermarket cat? Found some by Eastern and of course Magnaflow. Also I've seen Davico's.

Sorry if this is a rehash, but I've been doing a lot of searching on the subject. I know I probably should replace at least the first sensor. I've had the truck looked at and am pretty confident that the cat damage has been caused by something already fixed. I do wonder if it would be best to replace both sets of cats at the same time to avoid the same expierence in the near future with the other one. I also wonder if there is a negative side of running one side stock and one side aftermarket. I'm guessing no.

Thanks!

 

There is a special deep socket with an open side slot to use for OX sensor removel.
The cats have a ceramic honey comb substrate coated with rare metals.
If the substrate breaks apart, the exhaust flow can cause the parts to move in the case and make noise.
Given the age, I would advise you replace the whole assembly so all is new and will not give another issue to address again later, as long as you have the truck.
Going back later cost more labor and expense about equal to replacing the whole assembly one time.
Good luck.

 

You need an O2 sensor socket or a boxed end wrench preferably a 6 point to avoid rounding the sensor's flats.

The noise you're talking about, is it a diesel or knocking noise? There is a TSB regarding those sounds which is considered normal by Ford. According to Ford it's the engine's firing pulses coming from the light-off (closest to engine) converter. The noise will be there at idle but go away as you start to drive. There is a wrap kit that can be installed to reduce the noise but it's pricey. My 02 makes that noise fairly loud on the right side.

 

Thanks. I knew there had to be a tool involved with this. Did a search on it an now I know what to look for.

When you say "whole Assembly" are you also talking the exhaust pipes and muffler besides both cats and all sensors? Even with 130k miles on it they look in fairly good condition considering the WI winters.

The noise was actually diagnosed by my Mechanic when I had it in for a pre trip inspection. I didn't notice it much. However the engine light has also been going on do to the cat failures. So I'm pretty certain it is the cat breaking up. Thanks for your info.

 

Ok, that sensor will need to be replaced for sure. The converters on F series rarely fail unless the O2 sensor starts to get out of whack, even if there are no sensor codes. If you have sensor codes, then the sensor is definitely shot. The sensors output voltage drops over time, which the computer interprets as a lean condition. This causes the vehicle to run rich, which in turn damages the cats. Add a slight misfire or just incomplete combustion on one of more cylinders, that leaves unused oxygen, which then mixes with unburned fuel in the cat, causing it to overheat.

If you need to replace the sensor anyway, you can cut the wire at the base of the sensor and get a closed end wrench with six sides on that sucker. Then you can apply as much torque as you need to break that loose. Also soak it with PB Blaster a few hours ahead of time to give it your best shot. Make sure you use anti-seize with the new one. Running an appropriate sized tap to clean the threads probably isn't a bad idea, the correct size is 18mm x 1.50 pitch.

As far as the cats, go for the Eastern cats, they make a better product than anyone else at this point. Magnaflow is having major issues with their catalyst, Davico uses Magnaflow cats.

 

Great info.

I've hit it a couple of times already with PB blaster. I was hesitant to cut the wire on the sensor because I wasn't sure how I'd replace it all. I was trying to trace it back to see where the wire starts or plugs in. I'd guess that they probably have a plug end at some point.

Eastern cats are what I'll focus on than. Seems like they are priced a pretty good anyway.

Remaining questions.
1.) Does the exhaust have to come off (or how much of it) to get the cat off.

2.) Do I replace both Cats - Has been somewhat answered. I'm guessing I probably should AT LEAST replace the sensors on that one too. If this one has been damage from over heat prior to this, I'd guess the other side probably was exposed to the same conditions and will probably fail early also.

3.) Pipes and Muffler seems to be in good shape, But since I'm doing all this fiddling already, am I best to replace that too so to avoid it in the future.

 

I'd only replace the cat that had the code against but also the two front sensors. My reason is only based on I had to change converters on two 07 Expedition's due to misfire/overheat failures. The quality of the converters were fine but the pipes attached where smaller than oem and definitely not stainless. The fit and finish of parts were not what I would call quality. I had to grind welding slag from inside of one O2 sensor bung so the sensor would fit. We didn't buy oem at the time as they were not available. The price difference between oem and aftermarket was huge. The new converters have been running fine for over 1/2 year so far.

 

I second that, just replace the cat that has issues. Thats part of the greatness of the Ford design, you can replace just the one cat. With a Chevy, you have to replace them both.

 

no need for a special tool. try running the truck for a little bit, then back it out. if not, use a propane torch and hold it around the bung.

 

I got the sensor disconnected.

I'm really having a difficult time getting the cat off still. I'm thinking about cutting off parts to make it easier to get off. I took off the first muffler bracket hanger to give more room for pulling and pushing. This is the Passenger cat with the pipe going accross the middle of the truck to connect to the driver side cat. There is sort of a hang up on that bracket. The nut is off the bracket but the bolt hang on to the pipe. Up front I thought once I had the sensor off, I'd be able to slip the cat pipe off the manifold bracket, no such luck.

This is my first time trying something like this. Please give me a suggestion or two.

 

I hope I'm not becoming a pest. But seriously, someone has to be able to tell me if I have to remove the exhaust to get the cat off. I'm also starting to wonder if I need to remove the driver side cat to get the Passenger cat off.

I don't have a lot of fancy tools and I'd like to avoid cutting pipes with my hacksaw if possible. I'm starting to think that might be the best option. However if I need a hacksaw to remove it, I'm wondering how I'll be able to put a new one on.

My plans are to use a aftermarket bolt on.

 

You need to loosen the drivers side pipe from the exhaust manifold. This will allow you enough room to move the y pipe going from drivers to passengers side enough to get the bolt out of the hanger. That will allow it to drop down enough for you to remove and install what you need.
Once you install the new cat, put the bolt back in the hanger but do not tighten down. Align and tighten the pipes to the exhaust manifolds.
Then tighten the hanger bolt.

 

thanks so much! I was starting to figure that's what I'd need to do, but didn't want to do it if it didn't need to be done. At least the driver's side is easier to get at.

 

Had time to work on it tonight. Got the Driver side Cat off (way easier than the passenger side). However, bad news, because it rattles and pieces come out of it. I didn't know that one was bad too.

I have the passenger side cat completely loose, however I'm still unable to get it out of there. I have an FX Crew. I took one of the skid plates off, but I think I might have to saw. I can't quite squeeze the upper pipe past the manifold to allow the other end of the pipe to drop down where I might be able to pull it through if I could. But if I saw, how am I going to get a new one back in there in one piece?

Do I have to remove the transmission crossmember? That seems like I could mess something up if I do.

 

I don't know about the F150 as I just bought my 02 and have only been underneath to change the fuel filter. My experience with two 07 Expedition's however, was that the trans crossmember had to be removed the get the pass side converter out.