Failed smog on high HC and NOX

[amcink]

Just failed on my 86 325e. Had new oil, techron, and 15miles freeway drive and rev up to 3500 but failed. What could it be?

[jlevie]

High HC and high NOx could be from the engine running lean (intake leaks, fuel system problem, dirty injectors, etc) or it could be that the catalytic converters have failed. The first actions should be to make sure that the engine management system is working properly. Only after that should replacement of the catalytic converts be considered.

[amcink]

The car was parked 4 years and when it was raised to fix the muffler hangers i saw the cat and it seems that the insulation was coming apart. I suspect that the cat is bad since spark plug are new, fuel filter new, injectors clean with techron twice, the intake gaskets are new since i did a refresh to the intake.
Any other thoughts?

[jlevie]

A failure of catalytic converters is almost always the result of a problem in the engine management system. Replacing the converters will gain temporary relief, but unless the engine management system problems are corrected the new converters will soon fail.

[amcink]

In regards of the NOX my car is running "cold" it hardly achieve the middle. The needle stays in the first quarter mark and goes up on idle but never to the middle and when running it drops to just above the quarter line but never raise to the middle and stays there.

[Mr. Tasty]

may need to swap the thermostat.

[amcink]

may need to swap the thermostat.

it is new.
I did the time belt,water pump and thermostat recently and got the 88C thermostat

[amcink]

Ttt

[amcink]

tt

[Myster-E]

Had an m20 with the same problem. Check the cap &rotor.

[amcink]

Planing to do the following
-new cap and rotor
-new O2 sensor
-check my spark plugs to confirm if it is the correct - if not then get something "cooler" (what is the correct plug to use?)
-new temp sensor
-send injector to be repair and flow test-match
-take AFM apart and clean it
-try to find a leak (I need to do this DIY- any help is welcome)

Then try for a second test - please advice

If this does not do it then will have to change cat

[bernzpeed]

replace the o2 sensor & cat, done

[amcink]

I installed a new O2 sensor and I failed for the second time; I will change the cat ($200 installed) and try for the third time

[RCM3]

I failed smog with high NOx and slightly elevated HCs from a leak in the exhaust manifold coming from the joint before the O2 sensor pictured below, maybe check to see if you have any similar leaks? I fixed the leak and passed with low numbers all around. Good luck.

[amcink]

Getting a new Catalytic today. Will go for smog tomorrow after getting real hot.
I checked for leak but I have non (did not do a smoke test)