2005 Explorer Catylitic Converter problem

[Timmy2933]

I have a 2005 Ford Explorer Eddie Bauer 4.0L V6. The idol is really rough and it kind of jerks and jumps as i drive it at any speed, and seems to lack power on and off at times. The check engine light is on and flashes sometimes. The Driver's side cat was also making some metal rattling noises.

I had a friend of mine, who is a mechanic, tell me that the catylitic converter is toast and is most likely causing a misfire. Well the cats on this truck are part of a whole Y-pipe system. Every shop is telling me that they will only replace the whole Y-pipe assembly with a direct fit part for a "low-low price" of around $1100. $800 for the part and about $300 in labor.

I have seen after market cats for $100 and less. Would it be possible to just cut out the bad cat and weld in the aftermarket cat and save me a ton of money?

 

[n2audio]

A couple months ago I went through the exact same process you're going through but with a V8 (aviator). The truck had been running fine, but the rattle of the cat (which I thought might be engine/trans) was driving me crazy.

The consensus seemed to be it wouldn't be worth the effort to cut and replace. A random guy or two on the various forums I frequent claim it could be done, but I didn't get the impression the results would be very reliable - and definitely not reliable for very long.

Two shops told me the same thing - can't cut/replace one cat.
I got two quotes on replacing the whole system -- $1100 and $990.

Being the glutton for punishment that I am - I decided to buy the system from walker. I got it on a sale for $420 after rebate. I have not made the repair yet. The truck is still running fine. I'm hoping to find replacement time within the next few weeks.

 

[cross6]

I would get someone to check out your timing chain. It can sound like a cat and will cause misfires on one bank if your timing jumped.

 

[Timmy2933]

Thanks for the advice. I hope it's not the timing chain because I had that replaced a few months ago. It ran fine after the repair and then it all if a sudden ran extremely rough and a mechanic found that one of the fuel injectors was not connected properly causing a misfire. Fixed that issue and the truck ran fine again. About a week later I noticed the rattle sound and determined that it was coming from the catylitic converter and the truck was running rough again. A mechanic told me that sometimes a misfire can ruin a catylitic converter and vice versa a bad cat can cause a misfire. So I'm assuming that the fact that my cat is bad it's causing the truck to run rough. But I'll see what else I can find. I'm going to have the codes scanned this weekend.

 

[lincolnshibuya]

I
I had a friend of mine, who is a mechanic, tell me that the catylitic converter is toast and is most likely causing a misfire. Well the cats on this truck are part of a whole Y-pipe system. Every shop is telling me that they will only replace the whole Y-pipe assembly with a direct fit part for a "low-low price" of around $1100. $800 for the part and about $300 in labor.

I have seen after market cats for $100 and less. Would it be possible to just cut out the bad cat and weld in the aftermarket cat and save me a ton of money?

Not sure how your mechanic-friend came up with that conclusion, a "misfire" will kill your catalytic converter, not the other way around. I won't put in a new catalytic or aftermarket ones because sooner they'll toast too. You have to eliminate the misfires first (usually a check engine light) and then do the cats after.

 

[Carguy3J]

Not sure how your mechanic-friend came up with that conclusion, a "misfire" will kill your catalytic converter, not the other way around. I won't put in a new catalytic or aftermarket ones because sooner they'll toast too. You have to eliminate the misfires first (usually a check engine light) and then do the cats after.

Actually, a bad cat can cause all kinds of driveability issues, including misfires. A clogged cat drastically increases back pressure, and can, therefor,prevent the cylinder from filling up with the proper fresh air/fuel charge. If it can't get the "old" combustion gas out, then it can't get a fresh, burnable, charge in. If the engine/spark can't light off the charge in the chamber properly, because it isn't the right a/f ratio, then that would be a misfire. That it turn, will send more unburned fuel into the exhaust, causing further damage to the cat.

You are right, that just replacing the cat will only lead to another failure. However, its not a question of replacing it "later", after the misfire is fixed. Because, you can't really fix the misfire properly with a clogged/damaged cat. Its really more a question of fixing everything that needs to be fixed, at the same time, since the failures are related/connected to one another.