how to tell if cat is no good?
07-08-2011, 07:19 PM
#1
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1997 e 420
how to tell if cat is no good?
how do i know if i have a plugged cat? i have misfires on 5 6 7 8 it's not the coils or wires or plugs .....
when cold it seems to run good for a few minutes then it starts chugging and setting the codes...
when cold it seems to run good for a few minutes then it starts chugging and setting the codes...
Last edited by heebee; 07-08-2011 at 07:23 PM.
07-08-2011, 10:25 PM
#2
MBWorld Fanatic!
Open the exhaust
on that bank or remove the pre cat o2 sensor that side and see if lowering back pressure clears the misfires.
Or give the (cold) cat a good thump with a gloved hand and listen if it rattles.
Or shoot it with a non contact infrared temp gun for and aft of the primary cat on each side. You should see a significant difference for and aft in temp indicating that the cat is functioning properly and coming to temp.
Aft temps will be higher.
If not as high on the drivers side bank... therein could be your problem.
Other issues on M119 engine running through deep water recently?
Or give the (cold) cat a good thump with a gloved hand and listen if it rattles.
Or shoot it with a non contact infrared temp gun for and aft of the primary cat on each side. You should see a significant difference for and aft in temp indicating that the cat is functioning properly and coming to temp.
Aft temps will be higher.
If not as high on the drivers side bank... therein could be your problem.
Other issues on M119 engine running through deep water recently?
07-08-2011, 10:35 PM
#3
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1997 e 420
no water... thanks i will get it up off the ground and see if i can follow your instructions ... thank you very much for getting back to me .. i let ya know what happens....
