Catalytic Converter - testing?
 

How would one go about testing for a plugged or disfunctional Catalytic Converter (California)?

I've had intermittant power loss - see discussion at the following link:

http://www.peachparts.com/shopforum/ml-gl-g-wagen-r-class-unimog-sprinter/69113-ml320-loses-gains-power.html


and I don't believe that I have fuel pump problems, as I replaced both of them myself approximately 1 year ago.

I am getting some smell from underneath the passenger compartment, but it is more of a sweet fuel smell then a rotten egg sulfer smell.

Is there any inexpensive fault isolation that I can perform on the Cat prior to going to the expense of replacing it?

Thanks in advance for your suggestions.

The clogged cats in my travels have not caused intermittent problems.
They would consistently "hit the wall" at a certain speed, and positively slog under load, like when climbing a hill.

Just my results.

I'm sure there must be some sort of vacuum pressure test that can be performed for a positive diag, though I do not know the specifics.

Best of luck.

csnow,

Actually, the intermittant problems only occur under constant load, such as in hwy driving or during sustained hill climbs.

I noticed the problem when driving up to Mt Shasta over July 4th weekend, when I hit about 2500 ft in altitute on I-5.

Unfortunately, the way I have determined a cat to be clogged in the past was to partially unbolt the front connection flange, then test drive to see if the problem went away. A little noisy, and not very 'technical', but definitive!

If your 124 is setup like mine, it is all one piece, so this cannot be done.
Seems to me I saw a post go by on how you can test for this with a vacuum gauge. You might try a search.

Steven,

You can use a simple vacuum gauge to chrck for restricted cats. Tie in to manifold vacuum. Your idle reading should be around 16-20 inches at sea level. You lose 1 inch of vacuum every thousand feet. Run the engine up to about 3 grand and hold. The vacuum should go in the toilet briefly and climb immediately to a value higher than idle. If it is considerably lower, chances are you have a restricted cat or retarded valve timing. When did you last replace the fuel filter? Have you done a pressure anddelivery rate check?


Good luck,
Peter