Engine won't rev past 4500rpm even in neutral?

[Rifter]

Just hit the cat with a hammer, if you hear any rattling you are screwed, if you hear nothing rattling around its probably not the cat.

 

[DaTT]

Hitting a cat with a hammer can damage it.

 

[NutBucket]

Just hit the cat with a hammer, if you hear any rattling you are screwed, if you hear nothing rattling around its probably not the cat.

That's terrible advice. I had a rattling cat for years that otherwise worked fine. Hitting a clogged cat will accomplish nothing.

 

[Puffnstuff]

When I had a cat go bad on my years ago I unbolted it from the exhaust and when I turned it up the contents drained out like sand. It was causing the engine to stumble around 2500rpm but once it was cleared out it ran okay. You really need to read the engine codes so you don't throw money at the wrong things.

 

[Rifter]

In case it wasnt obvious i meant a rubber hammer i didnt think i needed to specify that but i guess i should have....

And if your cat is rattling its a ticking time bomb, period. That means the inside components(which look like small balls about golf ball sized) are loose and will eventually plug it up, a brand new cat has nothing loose inside of it and isnt supposed to ever have loose components inside of it. So finding out if its rattling will indeed accomplish something it will accomplish letting you know your cat is either good or bad in a very fast and simple manor.

Also Most of the rattling people hear from there cats are not actually the cat but the heat shields so also keep that in mind.

 

[NutBucket]

Eh, I ran that cat for years and it still passed SMOG check with flying colors.

 

[Rifter]

Eh, I ran that cat for years and it still passed SMOG check with flying colors.

Cats dont actually do as much as the greenpeace types would have you believe, i passed aircare(our version of smog testing in bc, canada) with a old camero with a 350 and 2 hollowed out cats, as in i cut them in half removed the insides completely 100% and put them back together and on the car. and passed each year with less than 30% of allowable limits. So either the limits are to high or cats dont actually do alot, not thats measurable anyways.

 

[dave_the_nerd]

Cats dont actually do as much as the greenpeace types would have you believe, i passed aircare(our version of smog testing in bc, canada) with a old camero with a 350 and 2 hollowed out cats, as in i cut them in half removed the insides completely 100% and put them back together and on the car. and passed each year with less than 30% of allowable limits. So either the limits are to high or cats dont actually do alot, not thats measurable anyways.

I've known more than one car enthusiast with similar experience. Here's the problem - most people are not car enthusiasts.

If an engine is running perfectly, the FA mixture is dead on the money, it'll burn the fuel cleanly and evenly, and you'll stand a decent chance of passing emissions (especially if they're grading on a curve and allowing higher emissions for older cars and/or trucks. Also depends on the type of test. Some, they're just checking the computer. If the ODBII port says nothing wrong, you pass the test.)

But, if the engine is NOT running perfectly (and hate to say it, but many aren't), it's very, very bad mojo. It's not you the CC is protecting us from, it's that guy who's been ignoring that funny tapping noise for the last 50,000 miles and put duct tape over his CEL.

Evidence: people fail emissions tests all the goddamn time.

 

[yhelothar]

I've known more than one car enthusiast with similar experience. Here's the problem - most people are not car enthusiasts.

If an engine is running perfectly, the FA mixture is dead on the money, it'll burn the fuel cleanly and evenly, and you'll stand a decent chance of passing emissions (especially if they're grading on a curve and allowing higher emissions for older cars and/or trucks. Also depends on the type of test. Some, they're just checking the computer. If the ODBII port says nothing wrong, you pass the test.)

But, if the engine is NOT running perfectly (and hate to say it, but many aren't), it's very, very bad mojo. It's not you the CC is protecting us from, it's that guy who's been ignoring that funny tapping noise for the last 50,000 miles and put duct tape over his CEL.

Evidence: people fail emissions tests all the goddamn time.

I had a miata that burned oil. It failed smog. I replaced the cat and it scored ZERO across the board in emissions.
Maybe the poor emissions could've been fixed by fixing the seals in the engine to prevent it from consuming oil, but the cat definitely did a tremendous job.

 

[yhelothar]

Update: I got the bluetooth OBDII and the IR thermometer. No codes reported by OBDII. Running the test feature in the Torque Pro app showed a few misfires. http://i.imgur.com/eWwbPf7.png

Not sure if it's significant. It did have a misfire issue a 1-2years ago that showed a CEL and I replaced the plugs and that fixed it.

I looked under the van and there's actually two cats. I tested pre and post temp of the second cat. Pre temp is ~600F, post temp is ~300F, so that does strongly support a clogged cat. I'm gonna unbolt it and see how much it helps.

I hope it's just one of them. It's going to suck buying two California cats.

Update 2: I unbolted the second cat. It didn't help. Maybe the first cat is the culprit. I thought the first one was ok because it tested 600F post cat.

 

[HitAnyKey]

I had a plugged cat on my old Firebird, no misfire issues but definite lack of power and wouldn't climb to higher RPMs. Made it tough to drive since it was a stick. Also smelled like rotting eggs, notice any odd smells from the van?

OP: After reading the thread, I am pretty convinced what 96Firebird wrote is your problem.
Youtube has a few great vids that show you how to check without buying anything. I would review them as well. Otherwise you could take it to a decent muffler shop for an inspection.

 

[yhelothar]

OP: After reading the thread, I am pretty convinced what 96Firebird wrote is your problem.
Youtube has a few great vids that show you how to check without buying anything. I would review them as well. Otherwise you could take it to a decent muffler shop for an inspection.

Yup I just took off the first cat too and ran it straight pipe. Damn that mini-van got really peppy.

 

[Pulsar]

In case it wasnt obvious i meant a rubber hammer i didnt think i needed to specify that but i guess i should have....

And if your cat is rattling its a ticking time bomb, period. That means the inside components(which look like small balls about golf ball sized) are loose and will eventually plug it up, a brand new cat has nothing loose inside of it and isnt supposed to ever have loose components inside of it. So finding out if its rattling will indeed accomplish something it will accomplish letting you know your cat is either good or bad in a very fast and simple manor.

Also Most of the rattling people hear from there cats are not actually the cat but the heat shields so also keep that in mind.

Huh? I've never seen a catalytic convertor with 'golf ball sized balls' in it. Every cat I've seen has a linear ceramic substrate. Can you link to a picture of one like you describe? I'd be interested in seeing it.

 

[Rifter]

Huh? I've never seen a catalytic convertor with 'golf ball sized balls' in it. Every cat I've seen has a linear ceramic substrate. Can you link to a picture of one like you describe? I'd be interested in seeing it.

https://www.catalyticconvertersonline.com/x-how-a-catalytic-converter-works-1

Top pic, pellet type. The one i cut open probably had 200ish of them left, looked like it could have had 2-3 times that many originally some had disintegrated.

 

[bruceb]

Most of them are either pellet or honeycomb types. And if you should need a new one, Magnaflow makes replacement High Flow converters that are legal ijn most states. I think they also have some with CARB certification for California use.

 

[yhelothar]

Most of them are either pellet or honeycomb types. And if you should need a new one, Magnaflow makes replacement High Flow converters that are legal ijn most states. I think they also have some with CARB certification for California use.

I ended up taking it to a muffler shop. It was cheaper than any of the small list of CARB approved ones I could find online. It ended up being a reasonable $250.

 

[NutBucket]

That's a pretty good deal. Nobody will ever know if the sucker is CARB approved. It's just a racket by the state to collect more fees.

 

[bruceb]

Well $250 parts and labor is a reasonable price.

 

[yhelothar]

That's a pretty good deal. Nobody will ever know if the sucker is CARB approved. It's just a racket by the state to collect more fees.

Nah there are actually markings on the cat with the specific serial that needs to match in their database or you won't pass smog.

Well $250 parts and labor is a reasonable price.

Indeed. It included quite a bit of cutting and welding.

 

[NutBucket]

Nobody will ever check for those markings. Seriously.

 

[DaTT]

Most of them are either pellet or honeycomb types. And if you should need a new one, Magnaflow makes replacement High Flow converters that are legal ijn most states. I think they also have some with CARB certification for California use.

Be careful with hi-flo cats as they don't heat up as quickly as regular ones and can throw CEL codes. I have Hi-flo on my car and had to have a tune put on to turn off the rear o2 sensor to keep the CEL off.

 

[yhelothar]

Nobody will ever check for those markings. Seriously.

I failed smog before when the smog guy checked and found my cat had an executive order that was rescinded. https://www.arb.ca.gov/msprog/aftermktcat/aftermktcatdbase.htm
I would not want to risk this again by buying an unapproved cat. That's money down the drain if they do check and you have an unapproved cat. Not worth the gamble. You can't even try to take it to another smog station hoping you'll get lucky because a record of your failed cat gets sent to the DMV.

 

[Pulsar]

https://www.catalyticconvertersonline.com/x-how-a-catalytic-converter-works-1

Top pic, pellet type. The one i cut open probably had 200ish of them left, looked like it could have had 2-3 times that many originally some had disintegrated.

Thanks! I did emissions work for GM for a couple years back in the 90's and was only familiar with the monolith and foam types.