Why so many Cats?

[Kim]

I was under my truck today replacing the fuel filter and I noticed what appeared to be five catalytic converters under there.
One on each downpipe from the manifolds, one in the crossover pipe, and two in the exit pipe....all before it even reaches the edge of the single cab. Crazy.
Is that for real? Or maybe some of them were something else, like maybe resonators or something?

 

[Roert42]

I’ve seen four cats.

new edge generation mustangs had four. Two for each bank before the y.

I would guess that at least one was a resonator, but that’s just a guess.

 

[pjtoledo]

pictures please.
are you sure some are not welded on heat shields?

 

[racsan]

Both my 2011 escape & the ‘06 HHR had a resonator in the exhaust system. Both are gone now, had rusted out at the front weld so just removed them & have a pipe section in its place. The actual muffler on the escape is huge, then theres a small muffler at the very end of the system back by the rear bumper. I think it has a cat on both manifold down pipes and one after they Y together. Its almost too quiet, I like to be able to hear the engine. Not a problem with the ranger, everyone hears it-especially when its cold and Im going up through the gears, backfires between 2-3 shift every time!

 

[Kim]

I'll get some pics tomorrow.

 

[Kim]

 

[Kim]

^ first pic is the three cat looking things; here's

the fourth...

 

[Kim]

And the last one before the catback system:

 

[pjtoledo]

damn, replacing those would be the cost of a new truck.

my 2000 4x4 auto only has the last 2. it's also a 3.0

 

[Roert42]

Surely does look like five cats to me.

I wonder is one or two are empty place holder type deals?

 

[Roert42]

Also possible that a couple of them are after the second o2 sensor and will have no effect if removed.

On my mustang I removed the four OEM cats and replaced them with two “hi flow” aftermarket ones. I was replacing the whole exhaust, headers and all, and have not had an issue with the readings on the second set of sniffer o2 sensors.

 

[pjtoledo]

is your Ranger flex fuel?
mine is, with only the 2 cats. also 4wd auto vs your 2wd manual.

 

[cbxer55]

damn, replacing those would be the cost of a new truck.

my 2000 4x4 auto only has the last 2. it's also a 3.0

Where I live, there's no smog check. I'd toss them all in the scrap heap. Whatever cats my 98 Ranger has apparently don't work anymore, exhaust smells like a good old fashioned hot rod. My Lightning had four, deleted the back two and replaced the front two with high flow cats years ago.

What has me baffled though, is yeah, the CAT monitor is INC. But, no check engine light and no codes. Some months ago, got caught in a heavy rain storm, truck died coming home from work. Had a code for the cam position sensor. Replaced it. Previous to this, had four codes, P0171, 174, 133, and whatever the code is for inoperational EGR (disconnected). When I reconnected the battery after the Cam positions sensor swap, the codes have vanished ever since. Nothing. Truck runs awesome. I don't know what happened. The Gods smiled down on me I guess.

 

[gw33gp]

Normally, there is only one pre-cat each side of the Y-pipe and then one or two main cats after the Y-pipe. Your left side of the Y-pipe with the two cats kind of looks like it is not OEM. Are you sure it has not been repaired at some time?

The pre-cats are used to start functioning quicker at start up until the main cat(s) get hot enough to start working efficiently. They are smaller and closer to the head so they can get hot sooner. The left pre-cat on my 4.0 is directly under the transmission and I recall it being more horizontal than what yours appears to be. You left pre-cats appear to be smaller then the right pre-cat, which is kind of suspicious also. Your rear O2 sensor is between the two main cats and that it correct.

Unless you are having a problem with the way your engine is running, I would not do anything with them. Cats have very little if any affect on performance unless they get clogged or someone has tried to route out the interior.

 

[cbxer55]

Or some enterprising individual has cut them out and sold them for scrap.