converters

[mlm0]

Is there an easy way to determine is one, two or all three of my cat converters on my 89 vette are bad or good. I'm assuming that the small ones on each side are also a converter. don't know why I have three of them thanks in advance Mike

 

[WhalePirot]

Searched, then avoided any and all eHow finds. Past experience has demonstrated the useless nature of those posts.

I recalled a vacuum gauge related procedure so this may be of value:
Testing a catalytic converter at home - Online Auto Repair | Diy Car Repairs | Automobile Information


I do know that a real rich or oily exhaust can damage and/or clog a cat. Mods that lower 'normal' engine vacuum can fool an unaltered ECU to add fuel b/c it 'thinks' the go pedal is mashed more than it is.

 

[LLC5]

Is there an easy way to determine is one, two or all three of my cat converters on my 89 vette are bad or good. I'm assuming that the small ones on each side are also a converter. don't know why I have three of them thanks in advance Mike

If a catalytic converter is doing it's job properly there should be about a 100 degree difference between the inlet of the converter and the outlet. Good luck with it.

 

[FForward]

An easy way to check your converter is by checking your back pressure. This can be done by hooking up a compression gauge to the exhaust at the O2 senson. A reading of 3-5lbs is good, anything above that would mean a restriction. Hope that helps you......Bill

 

[LLC5]

An easy way to check your converter is by checking your back pressure. This can be done by hooking up a compression gauge to the exhaust at the O2 senson. A reading of 3-5lbs is good, anything above that would mean a restriction. Hope that helps you......Bill

That will check for a restriction, but not the operation of the catalytic converter.

 

[Hib Halverson]

An easy way to check your converter is by checking your back pressure. This can be done by hooking up a compression gauge to the exhaust at the O2 senson. A reading of 3-5lbs is good, anything above that would mean a restriction. Hope that helps you......Bill

1) Read statement "LLC5" made above

2) A compression gauge will be inaccurate at pressure levels that low. If you're going to measure back pressure you need a back pressure gauge or any air pressure gauge which a scale of 0-10 psi or so.

3) Nominal back pressure ahead of the main cat may vary widely depending on the cat and the design of the system.

4) The above test will not take into account the precats or "pup cats" which often are located ahead of the O2Ses and are usually more restrictive than the main cat.

My suggestion is that you take the car to an exhaust fabricator, scrap the precats and, if the main cat fails the "in-and-out temp test" suggested by "LLC5" replace the 24-year old main cat with a new unit.

 

[mlm0]

If I get rid of the pre cats, will my car still pass emissions check in Texas. Will muffler shop take them off for me. I was understanding they would not do something like that. Thanks of everyone for information Mike

 

[FForward]

1) Read statement "LLC5" made above

2) A compression gauge will be inaccurate at pressure levels that low. If you're going to measure back pressure you need a back pressure gauge or any air pressure gauge which a scale of 0-10 psi or so.

3) Nominal back pressure ahead of the main cat may vary widely depending on the cat and the design of the system.

4) The above test will not take into account the precats or "pup cats" which often are located ahead of the O2Ses and are usually more restrictive than the main cat.

My suggestion is that you take the car to an exhaust fabricator, scrap the precats and, if the main cat fails the "in-and-out temp test" suggested by "LLC5" replace the 24-year old main cat with a new unit.

I thought the post was to determine if the cats were a Go No Go and a easy way to find out. On the 89's the O2 sensor is before the pre-cats. Its a common practice in shops around here to use a compression gauge at the O2 or AIR injector at the manifold. Getting under the car to measure temps isn't the easy way for some of us who don't have lifts and special equipment. Just saying!

 

[LLC5]

I thought the post was to determine if the cats were a Go No Go and a easy way to find out. On the 89's the O2 sensor is before the pre-cats. Its a common practice in shops around here to use a compression gauge at the O2 or AIR injector at the manifold. Getting under the car to measure temps isn't the easy way for some of us who don't have lifts and special equipment. Just saying!

That would only check for a possible flow restriction, not a converter effeciency test.

A catalytic converter can have good air flow and still be bad