Do I need new catalytic converter?

[97LTD]

Hi I tried to find some information for my stock 1993 Ford Explorer Limited which did not pass the California emission test (smogII). I was wondering if I can ask anyone's opinions. The test results showed high NO (PPM) with a max allowable of 501 but measured 606 which is little over a 100 higher than allowed.
Does this means a bad catalytic converter that needs to be replaced? Does my 1993 X needs only one catalytic converter?

Needs some help with info before I can try to get it fixed. Thanks for the time

 

['97 V8]

I believe the 4.0's came with 2 cats. Obviously a cats job is to get rid of the NO emiisions, but there have been people on here who have passed emmisions without cats in Cali(hallowed out). But imo you would need new cats.

 

[uh60james]

I'm sure they sell a product at your local auto parts store to help you with passing emissions you just add it to the crankcase or the fuel and it will lower your emissions long enough to pass the test.

 

[MrShorty]

Could be a catalytic converter. Could be a few other things, too.

High NOx is a result of excessive combustion temperatures. EGR system is installed to lower combustion temperatures and reduce NOx. Does your '93 have an EGR system (not all '93's do)? If so, then I would probably start by verifying that the EGR system is functioning as it should.
Even without an EGR system, a lean mixture will burn hotter. Check for things that could make it run lean: vacuum leak, low fuel pressure, etc.
In all of this, I think the best first place to start is by pulling codes from the computer to see if the computer can see anything.

 

[97LTD]

OK thanks guys for the input. I'm not sure if my 1993 X does have EGR I will take a look. Also, the CEL light did not come on (the bulb does illuminate at start up but does not stay on) I wonder could a failed catalytic converter failure cause a CEL light to come on? If that's the case, I guess the computer for CEL is faulty. My gas mileage still remains normal avg about 20-21 mpg on freeway. The 1993 X mileage is at 236K so I'm guessing it's time to replace catalytic converter.

 

[97LTD]

Problem solved did the emission diagnosis and found that one catalytic converter failed. Replaced it and re test and passed. Thanks for the tips