i have a '99 dodge 2500 v10. it has 108k miles on it now. it still runs smooth as can be and does not burn any oil. it has lost serious power recently. it passed smog fine recently. i am thinking a clogged cat would cause a serious loss of power. i want to know if there is a sure way to find out if that is the problem. the cat is expensive ($600-$1100) and it isn't like i can buy a $100 auto part store cat that will simply weld on. i was thinking about cutting it out and running a test pipe. when i looked under it, it is a 2 in 1 out cat and making a test pipe would be quite a bit of work. i am not going to run it without a cat.

so is there any sure fire way to know if a cat is clogged. is there anything else that would cause a loss of power while the engine still runs and idles smooth and does not burn oil?

edit: i talked to the dodge dealer and they said it does not have a fuel filter. is this true? the air filter is clean.

...edit: i talked to the dodge dealer and they said it does not have a fuel filter. is this true? the air filter is clean.

Well not exactly true. It has an in-tank assembly which is sending unit for gauge, fuel pump, and fuel filter all in one. $$$

Does it still rev up normally? Have you tried tapping the cat with a hammer? Rattling can be a sign of a bad cat which is plugging off.

It would likely get hot as a mother...like to the point it would glow. I doubt you would have passed smog (or was this after your smog test?)

Can you pull the pipe off one side of the cat and look inside?

the cat is expensive ($600-$1100) and it isn't like i can buy a $100 auto part store cat that will simply weld on. .

Um, why not? is it flanged right to the manifold?

Cat on my Dodge got pluged and I lost 90% of power and the Exhaust Manifold was glowing red.

when my it happened on my ford, the inner wheel wells shrunk and did some funk things from the amount of heat that is generated.. I dont remember the temp gauge being any higher than normal but everything was sure hot.. throw the hood open and it was like throwing the oven door open..

when it happened on my toyota mini truck, i had almost zero power.. It happened within a matter of about 4-5 minutes. Cruisin down the freeway then i lose power, exhaust manifold starts to leak against the head... Oh shit this is bad.. I whipped out my die grinder and cut a 6" long by 2" wide gap in the exhaust right before the cat.. i did that right on the shoulder of the freeway in semi-rural Utah :laughing: it sounded like ass, i had less power than normal but i didnt blow any gaskets and i got home..

Which reminds me, every vehicle should have a york and an assortment of tools to go with it :laughing:

Um, why not? is it flanged right to the manifold?

pretty much. it is 2 in 1 out. the passenger manifold has a short pipe, about 6" to the cat. the driver side crosses over and turns directly into the cat.

i haven't noticed my manifolds glowing but i haven't looked. i just opened my hood but my truck had been sitting for about 15 minutes after a 35 mile drive. it didn't seem any hotter than normal under there. it may have had enough time to cool down a bit though.

i will drive it for a bit tonight and open the hood to see if the manifolds are glowing. the truck feels like it has a v6. it used to pull hard in od up the grades around here. now it needs to down shift to maintain speed.

pull the o2 sensors out for a short drive. If it runs better something is clogged. the hole is often just big enough to be a good vent

You might check ebay for some cheap converters. I was just looking for a replacement for my Subaru and they had aftermarket, direct fit converters for a pretty reasonable price.

From what you're describing I think your converter is probably plugged, but it is definitely worth checking first. One thing you might try is to see how much of a difference in pressure there is from the piping between the motor and the cat and the rest of the exhaust pipe.

You can unbolt the cat from the flange and run it around the block, or take it to an exhaust shop and have them test it. They can do a backpressure test and a temp test to see if the cat is bad.

or take it to an exhaust shop and have them test it. They can do a backpressure test and a temp test to see if the cat is bad.

i like this idea. i didn't know they could do a test to find out if it a cat is bad. do all exhaust shops do this?

You can do it at your house if you have some sort of a pressure gauge. Tap your exhaust both pre and post converter and measure the pressure drop across it.

Slam your door shut - did your truck rattle? That's a cat and the common noise I hear when mine dies. Which has happened a couple times now.

the first time I was cruising down hwy16 and suddenly my top speed was 35mph. AAA and $300 installed for a new high flow cat I was good to go again.

i like this idea. i didn't know they could do a test to find out if it a cat is bad. do all exhaust shops do this?

They all should be able to. I can't remember the numbers they are looking for, but they use one of those laser thermometers to check temp. For the back pressure, like mondster said, if you have a pressure gauge, drill a small hole in front of and behind the cat. Use a piece of metal tubing (brake line would work) stuck into the end of the hose on the gauge and check the pressure difference between the front and back of the cat. Don't drill the hole too large, you just want it big enough to get the tubing in.

This kind of spells it out.
http://www.aa1car.com/library/converter.htm

mine rattled on my jeep, I just went to the scrap yard and cut one off there. paid $20 for it. Worked GREAT! I'm sure I wouldn't find a v10 dodge there though...

mine rattled on my jeep, I just went to the scrap yard and cut one off there. paid $20 for it. Worked GREAT! I'm sure I wouldn't find a v10 dodge there though...

i didn't even think it was legal for a wrecking yard to sell cats. maybe that is just a california thing.

but yes, i doubt i would even find a v10 cat in any better shape than the one i have at a wrecker.

Put a vacuum guage on it if your cat is plugged it will show signs of it, usaully whe you start it vacuum wil be normal and then it will slowly start to drop. If your vac. guage reads 20 your cat is not plugged.

Go to cheap tool store by infared temp guage, shoot it pre cat and post cat. if exhuast is hotter pre cat than post cat your cat is clogged. Cats are burning off excess hydrocarbons and creating a substantial amount more of heat than if a test pipe was there, so if a cat is working properly exhuast is hotter post cat, if its clogged hot gas is backing up in system.

If neither of these give you a definitive answer, cut the mother w/ a sawzaw right at the cats and run it see if it runs better, it won't hurt it.

Maybe in CA exhuast shops are probing and looking at pressure drops but here on the east coast they are doing nothing of the sort. If you think its clogged you wack it and weld it back if you were wrong.

oh ya and i bet the cat is not clogged, whats the condition of the tranny.

What is the fuel press, have you checked?

mine rattled on my jeep, I just went to the scrap yard and cut one off there. paid $20 for it. Worked GREAT! I'm sure I wouldn't find a v10 dodge there though...

That is suprising as it is illegal to sell used convertors. I cant even legally install a used convertor without risking an epa fine.

What is the fuel press, have you checked?


no, i haven't checked.

i just towed my 4runner home and it was terrible. on grades that i used to be able to tow 70+ and accelerate up now i was down to 45. something i notice is that my torque converter doesn't unlock and it just bogged down. i also figure at that speed with it floored it should have down shifted into second gear. i did notice the power loss about the time the new transmission was installed. i think this is the first time i have towed with the new transmission but it seems to shift fine just driving around normally. even with the torque converter locked, i figure with a supposed 400+ lb/ft of torque it should still pull the grades fine. i don't understand automatic transmissions so i have no idea if that has anything to do with it:confused:

i still think i am going to have an exhaust shop check the converter. i guess i should check the fuel pressure also for shits and giggles. i need to figure it out. it doesn't make sense to drive a rig that gets 8-9 mpg with the power of my toyota:p

so what happened with this.............

I also would like to know.

I fear my F150's cats (which has 4 fucking cats on it!) are becoming clogged. I've lost a ton of power, my fuel mileage has gone to shit (down to 7 mpg from about 13 when I bought it 2.5 years ago), and it has developed a massive, and I mean massive exhaust leak (backpressure too high?). It does need a fuel filter, which could be part of the problem...

Either way, I am going to remove all the cats, gut one of my old ones, and install it after the Y-pipe to make it appear that I have one for visual state inspections...

Any Exhaust shop will test the Cat for free.
All then do is drill a quick hole, install a vaccum gauge and measure. You can buy those ones to thread into the 02 sensor as well to test.
But go to a exhaust shop, have them test it, if bad they may cut you a deal on a new one.

so what happened with this.............

nothing yet. i have been too busy to deal with it now. someone suggested fuel pressure. i may check that first. i am getting record gas mileage now. i actually broke the 11 mpg mark the other day. i only broke 10 mpg one time before and that was a 300 mile drive on all freeway. my normal commute mpg in it is around 8-9 mpg.

i would think if the cat was clogged i would be getting worse mileage because the engine would be working harder:confused:. either way, i need to figure it out. i can't be driving a 10 mpg vehicle that has no power.

I have a 99 Dodge v10, I also had a loss of power and an annoying rattling sound. Cut the cats off and replaced with tubing for now, I'd rather deal with the loudness than no power and 8-9mpg. My mpg and power is back but it sounds like ass and retarded loud (straight exaust 2 in 1 exits to the side), it's just temporary, I'm getting the Dynomax Flo X muffler part# 17552 and will install that instead of the cats. I already passed emissions with dead cats so it should be able to pass again without them. I did reweld the emissions lines to the pipes (some have them some don't).

Inexpensive cats, just find the right tube size: http://www.jcwhitney.com/autoparts/VehicleBrowse/tf-VehicleBrowse/s-10101/N-111+1999+200733181+600001717/c-10101

Stock exaust is about 2 1/4 OD before the cats

I like having a 488ci, but straight pipes are not meant for dodge v10s, v8 rules for sound:D

I just bought a 2000 with a V10 and a NV4500,and Im not playing games with this truck. After I correct the steering issues (box brace, aftermarket track bar and steering shaft) and throw some new tires on the truck, out go the manifolds to be replaced with stainless headers (they are going so cheap as of late) and my friends the cats are getting a enima to rid them of their load. And what to do with our little post cat O2 sensors? The litter box, a piece of pipe attached out of harms way with a O2 sensor bung that gets a copius ammount of fresh air. keeps the annoyance light off. Yes it works, I always give the send off to converters and litter boxes work dandy. performance as well as MPG gains are well worth it. In smogger states I know this means crap but where the man does the visual only We run dummy settups and hide the litter box. Half the people dont care and just want their fee and you gone anyways. Good luck with the converters. Also a V10 doesnt sound as good as my 440, or even a 318, but if it pulls like a train I frankly dont give a ________. happy fathers day.

Got a vacuum gauge? Put it on the intake and crack the throttle open with the air filter removed. The vacuum should almost immediately drop to nearly zero. If there is any hesitation in the vacuum dropping a cat can be suspected.