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clogged cat or ?

Posted by joe_mn (My Page) on
Sun, Feb 4, 07 at 17:48

96 dodge intrepid. I got a code 72 last fall, cat conv efficiency. it would come and go so I was not sure about its validity. the other day, the car flooded, -10F. I had to change plugs and it finally started but now it is running very rich. I am getting code 52 which means rich condition. my rear bumper is getting sooty from the black exhaust. is my exhaust plugged so the engine is running very rich or are my O2 sensors fouled by the flooding episode? dodges are sensitive to being flooded i have heard.


Follow-Up Postings:

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RE: clogged cat or ?

It's time to take it in to a qualified shop and have it diagnosed and tuned up; and yes, your catalytic converter may be clogged and/or posioned, and there could be malfunctioning sensors present. I'll bet that your fuel mileage has reduced. A clogged comverter will cause a reduction of vacuum which can mess up the system response.


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RE: clogged cat or ?

yes, mileage is way down. does the engine get feedback from the sensors right away? the manual says it does not read the O2 sensors for about 2 minutes. it runs bad as soon as it starts.


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RE: clogged cat or ?

You could check the leads and the coil(s).

Also might be in the EFI system...


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RE: clogged cat or ?

my mechanic friend said to check the plugs and see if any were wet now that it is "running". i did and only 1 is wet but all are black. thats with new plugs and only 200 miles of running. hmm, what would make all the plugs black? something they all have in common? maybe FPR? what is the situation here? car is running but very rich. runs bad when it is cold, supposed to be in open loop so it is not getting input from sensors yet it runs terrible.


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RE: clogged cat or ?

I still say that you should get a full set of diagnostics done at a good shop. However, in the interim, you may wish to check the operation of the MAP (manifold absolute pressure) sensor. By your description, the engine is running more rich than for startup, default settings. Check the connection and health of the vacuum line to the MAP sensor.

Test the electrical resistance of the plug leads. I don't know the recommended replacement schedule for yours, but its probably in the neighboorhood of every 30,000 miles.

If you are going to do your own maintence, a good repair manual is a must.

Another item that may cause a rich mixture is loss of, or erroneous, temperature signal to the engine controller. If this is in working order, a thermostat stuck open, lets the engine runs too cool to provide enough temperature signal to lean out the mix.


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RE: clogged cat or ?

the wires are less than 1 yr old. I did have a cracked vacuum line to the FPR. i fixed that and checked all the plugs last nite and took it on a 20 minute drive. ran ok, probably 80%. it started this morning in -5F temps. first crank and she fired. i took it to work. 4 mile trip. started fine after work. seems to run ok and the rich smell is gone but i do get a flucuating idle still. perhaps it will take several days to get the computer to relearn my driving habits. a visit to a shop with a scope is not a bad idea.


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