catalytic converter?

[bhw33191]

I read somehwere that a clogged catalytic converter could cause a problem similar to what i am experiencing. i.e. (bogging down and sluggish, surging with power). Could this be a likely cuase? My exhaust smells very strong and of rotten eggs so this could be it. I wasn't even sure if my car has a catalytic converter.

[j cAT]

Originally Posted by bhw33191

I read somehwere that a clogged catalytic converter could cause a problem similar to what i am experiencing. i.e. (bogging down and sluggish, surging with power). Could this be a likely cuase? My exhaust smells very strong and of rotten eggs so this could be it. I wasn't even sure if my car has a catalytic converter.

If you smell rotten eggs you have a catalytic converter...place your pressure gauge in the air pump check valve pipe fitting located at the valve cover and measure pressure should be below 10psi at idle...if it shoots upward the higher it goes the more its ''' plugged'''...

the reason you smell rotten eggs is your engine is too rich and the cat is working over time... cat should only work when the engine is warming up.... if you replace the cat with a new one and first don't address the mixture problem your vehicle may go up in flames....as the new cat will,,, with max efficiency start to glow a very bright red and then you will smell the carpet burning...



It is very possibe with the cat plugged the EGR now has more exhaust gas pressure and this is now causing the problems ..these are all interrelated...

you should have an old timer with experience with this type of vehicle look at it...

[bhw33191]

Originally Posted by j cAT

If you smell rotten eggs you have a catalytic converter...place your pressure gauge in the air pump check valve pipe fitting located at the valve cover and measure pressure should be below 10psi at idle...if it shoots upward the higher it goes the more its ''' plugged'''...

the reason you smell rotten eggs is your engine is too rich and the cat is working over time... cat should only work when the engine is warming up.... if you replace the cat with a new one and first don't address the mixture problem your vehicle may go up in flames....as the new cat will,,, with max efficiency start to glow a very bright red and then you will smell the carpet burning...



It is very possibe with the cat plugged the EGR now has more exhaust gas pressure and this is now causing the problems ..these are all interrelated...

you should have an old timer with experience with this type of vehicle look at it...

Thank you so much for the help! I really have a good feeling that this is the issue and i can finally get my car working again!! I know a mechanic who knows a lot about these cars and i'll talk to him about it (he's located in Hull if you've ever been there "Robin's Garage"). I think i might have him take the cat off and while he's at it install a flowmaster 40 for me (i can't wait!)

[bhw33191]

I also heard if you wack the cat with a screwdriver or something and you hear a dull thud instead of a more hollow noise then its plugged. And sure enough i heard the dull thud!

[silicon212]

Originally Posted by bhw33191

I also heard if you wack the cat with a screwdriver or something and you hear a dull thud instead of a more hollow noise then its plugged. And sure enough i heard the dull thud!

Somebody saw you coming, didn't they!

You're going to hear a thud regardless. The substrate material is ceramic honeycomb, you're not going to get any sort of hollow noise out of that.

[bhw33191]

Originally Posted by silicon212

Somebody saw you coming, didn't they!

You're going to hear a thud regardless. The substrate material is ceramic honeycomb, you're not going to get any sort of hollow noise out of that.

lol, ok then. I guess i'm going to take apart the carb this weekend.

[j cAT]

Originally Posted by bhw33191

lol, ok then. I guess i'm going to take apart the carb this weekend.

why are you going to mess up the carb ????

get the vehicle checked out by that old guy....stop wasting your money chasing your tail...chances are you have a plugged cat and because you have a 1983 the emisions testing is not required....


since you don't know how to use/test out your engine,,, bring to someone who does and ask questions as he looks at it ...

my quadrajet lasted 17years 380,000mi and I only replaced the in line gas filter thats it....this is not a simple job and I doubt you have the training to do this properly...

[bhw33191]

Originally Posted by j cAT

why are you going to mess up the carb ????

get the vehicle checked out by that old guy....stop wasting your money chasing your tail...chances are you have a plugged cat and because you have a 1983 the emisions testing is not required....


since you don't know how to use/test out your engine,,, bring to someone who does and ask questions as he looks at it ...

my quadrajet lasted 17years 380,000mi and I only replaced the in line gas filter thats it....this is not a simple job and I doubt you have the training to do this properly...

Yeah your totally right. Its just people kept turning me back to a carb problem and then a cam lobe problem, but this car has 49,000 miles!! So it COULDN'T be anything that serious. I just did the vacuum test and was happy with the results proving its a cat related problem. Vacuum resides at around 17 "when i hooked the gauge to the vac line that goes to the MAP sensor" and once i stepped on the gas, the gauge went down about 8-10 inches. btw that is an A$$ LOAD of miles you got on that quadrajet.

[bhw33191]

hey j Cat "or anyone else," i think there might be some debris in my carb "from changing the fuel filter and putting the additive in the tank and thats why i might need to take it apart, or do I? Is there anything i could do without the burden of taking it apart?

[j cAT]

Originally Posted by bhw33191

hey j Cat "or anyone else," i think there might be some debris in my carb "from changing the fuel filter and putting the additive in the tank and thats why i might need to take it apart, or do I? Is there anything i could do without the burden of taking it apart?

when changing this filter it is very difficult to get contaminates into the carb....also if you still think fuel supply is a problem you can replace fuel filter again and test the fuel pump pressure...cut open the fuel filter and see if the insides of the peats are loaded with rust as this is a possibility... if the fuel filter ruptured then it is possible that the carb has problems...if not leave it alone...



finally I see you have used you vacuum gauge to troubleshoot your engine this is how you can stop guessing as your results to me indicate a restricted exhaust....


the cat on your vehicle if original should be a very large flat bottomed type this is the good high quality cat....the smaller round type used in 84 has plug up issues....

[silicon212]

They stopped using beaded converters in the late 1970s, j cAT.

[j cAT]

Originally Posted by silicon212

They stopped using beaded converters in the late 1970s, j cAT.

I disagree ....MY 1983 delivered in june 1983 ordered from factory had the large flat bottomed cat...this is the one that lasts almost forever...the cheap rounder smaller ones plug up ...1984 this was when it was changed...as the same applies... my 1984 still has the bad one on it...

ya you got the one I'm talking about ....1983 had the expensive platinum beads in it...it was huge..

[silicon212]

Originally Posted by j cAT

I disagree ....MY 1983 delivered in june 1983 ordered from factory had the large flat bottomed cat...this is the one that lasts almost forever...the cheap rounder smaller ones plug up ...1984 this was when it was changed...as the same applies... my 1984 still has the bad one on it...

ya you got the one I'm talking about ....1983 had the expensive platinum beads in it...it was huge..

My 1982 Impala had the honeycomb cat in it. If you had an '83 with the octagon cat, it was retrofitted. Regulations enacted in 1979 effectively ended the older beaded cat - for lack of NOx control.

[bhw33191]

So even though i have the bigger cat which "lasts forever" it could still get plugged right? For the past 8 years my car has been turned on and turned off without a good highway run so i'm guessing carbon has built up as a result.

[silicon212]

Originally Posted by bhw33191

So even though i have the bigger cat which "lasts forever" it could still get plugged right? For the past 8 years my car has been turned on and turned off without a good highway run so i'm guessing carbon has built up as a result.

I've had more problems with those old beaded cats, the ones 'j cAT' states last forever, getting plugged. Perhaps I am an anomaly, perhaps not. Either way, the beaded cats are very restrictive by design, where the monolithic, honeycomb ones of newer design are much less so.

A very rich running engine can kill a cat (as well as the 02 sensor). Likewise, an engine with a chronic misfire can kill a cat. Both due to overheating as the unburned hydrocarbons burn inside the cat.

If you have a simple carbon buildup, a good, hard run can 'bake' the cat and remove the restriction.