Catalytic converter on 92 continental

[Willys]

Have 150,000 miles on it. Last year blew an exhaust manifold gasket on hard acceleration. Mileage is about 20 but engine seem sluggish. have replaced plugs, dist cap and rotor, plug wires and other misc mainentance.

How long should a cat last and how do you know when they go bad. Can't remember the price for new cats when I was at napa but remember I lost my breath for a second.

Any recommendations?

[MichiganTeddyBear]

92.. pre-OBDII, has EEC-IV...

about the only way I know of is to check the difference in back pressure from infront of cat to behind cat (should be very little diff, if you have some, its melted), and to compare the emmisions coming out of the tail pipe to test if they are working or not.

Since its pre OBDII, there are not any O2 sensors downstream of the cats (yes, cats, there is 1 for each bank). therefore, the PCM will not know if the cat is good or not, and wont try to adjust for it by screwing with the mixture.. Only way bad cats can really affect the running is if they are melted/plugged, causing high back pressure.

Cats can last from 1 mile to several hundred thousand, although I would guess between 80-160k is when most fail... In theory (repeat, in THEORY), they last forever.

if your in a state without inspections (like me), and you know a shop who is willing to due stupid stuff (or do it yourself), loose the cats.

[KENDO & MYRA]

have you changed the oxygen sensors ? that will boast your mileage

[KENDO & MYRA]

maybe if you get a emissions test for thr exsust gases to see what the numbers are..........................

[Willys]

I did find the following but sounds like a lot of work:

To test for a plugged converter, drill a small hole in the exhaust pipe right before the catalytic converter. Install a temporary hose fitting and attach a long rubber hose and a 0 to 10 pound pressure gauge. With the gauge inside the car, drive up a hill or accelerate and read the pressure. Normal is 2 to 3 pounds, restricted 4 pounds or higher.

[Willys]

I replaced the 02 sensors. But in looking at the following site it says that coolant will ruin a cat. I had the dreaded bad head gasket problem and wonder would the coolant plug it up as well as ruin it's normal operation.

http://aa1car.com/library/converter.htm