Catalytic Converters W124 103 1987 300E

[murphysf]

Hello

My 1987 has three catalytic converters.

There are two in the engine compartment coming off the exhaust manifold (referred to the front cats). These two front cats then feed into a single cat which is often referred to the rear cat.

Do the front two do most of the work and the single rear one is just a "clean up" cat.

Is there a way to test if they are effective?

I have a fluke digital infrared thermometer

What temperatures or temperatures should I see at the input and output of the CATs?

Thanks!

[Duke2.6]

Those are often referred to as "light-off cats". They are oxidizing only and reduce HC and CO during warmup, but have little effect once the engine goes into closed loop operation.

I measured and reported temperatures at the inlet of the main three way cat. Do the search I recommended in your other thread.

Duke

[murphysf]

As for the CAT I learned the Walker is not an approved California CARB CAT for my application. The Walker is approved only if I didn't have the two pre cats. My 300E is what they call a PC-2 Vehicle Class since it has 3 converters.

The correct CAT is the Magnaflow 338008.

[Usaguy]

whats interesting that in M103 after 1990 the pipes are the same but the 2 front ones don't exist (hollow pipes in front) at least outside of ca but who knows maybe ca too

[murphysf]

from what I understand cars with a smog pump did not have the front two pre cats.

my car does not have a smog pump nor does it have EGR.