• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

AZ Emissions Help

sneedes

NAXJA Forum User
Location
AZ
Just purchased a 1994 Cherokee XJ for my kid via craigslist. Didn't realize different parts of greater Phoenix didn't have to pass emissions. Bought a Cherokee that didn't pass emissions. Looking for guidance on the cheaper side.

4.0L
202,000 miles.

IM147 Inspection Information
HC Grams/Mile 2.06 HC Std 1.60
CO Grams/Mile 21.41 CO Std 20.00
NOx Grams/Mile 9.54 NOx Std 3.00

Notes:
Didn't "prep" for the emissions at all. Haven't ran a whole tank of fresh gas through since buying, no oil change yet, no CRC Guaranteed To Pass, didn't run hard before testing, etc.

Someone recommended exhaust header, catalytic converter, o2 sensors, PCV/CCV assembly and hoses. All those parts and labor adds up real fast.

These inspection results close enough to re-test or do something on the cheap, or am I looking at basically a whole new exhaust.
 
Well, for starters, it could be worse and you could be dealing with an '01 like mine that has three catalytic converters and four oxygen sensors. Or two pre-cats and one main cat, however you want to look at it. But for starters, I dont know how to read the emissions readout numbers you posted, but Im assuming your check engine light is on if it failed the test. Can you get it scanned and look up the codes online? That would be my first step. Then, while going off of that, I would replace the cheap simple things that usually go bad every now and then, i.e. gas cap, pcv valve, check the condition of the ignition system components just because. Look for simple easy things too, like rotten rubber elbows/connections that connect all the vacuum lines, or worn/leaky vacuum lines themselves. Check the wire harness and wires going to the oxygen sensor first before changing the sensor itself. Go over as much of the wiring as you can, just to be sure. Make sure it is all in good shape, or at least not damaged. It is time consuming, but you never know what was going on before you owned it. If you are able to find out that the catalytic converter IS the problem, you really dont have much of a choice but to replace it, but even then you could be economical about it. Head to a boneyard and purchase a used one roughly the same size, with the same size diameter pipe.
Its worth a try.
 
I don't know how to read these emissions numbers either. The AZ format uses seems to be different than most other posts I've read here.

http://www.myazcar.com/resources
> Vehicle Inspection History
> VIN: 1J4FJ28S7RL217429
> Test from 4/20/2018

I'm a '94, so I believe I'm prior to OBDII. Any other way to "pull" codes?

Checking wiring/O2 sensor...is this just checking the mV DC from the 02 sensor with a multimeter with car running? Red probe into wire clip/harness?
Black probe to a ground wire in the sensor, or against frame?
Expecting to see voltage g"bounce" between 100mV and 900mV?

Under the hood, I discovered there's no hoses attached to the elbow on the "rear" of the valve cover. Assuming that's going to be problematic for emissions?
 
I'm a '94, so I believe I'm prior to OBDII. Any other way to "pull" codes?

1. Get pad of paper and pen/pencil
2. Key in ignition, do ON-OFF-ON-OFF-ON over about 5 seconds, leave in ON
3. Record blinks of Check Engine light on pad. Codes are two-digits long, and are blinked out one digit at a time. short pause between digits, long pause between codes. Last code will always be "55" ("end of buffer").
3. (Alternate): Use phone or camera to video Check Engine light so you can replay at your leisure to transcribe.
4. Ignition off, go look up codes.
 
Following up for closure...
The advice for pulling codes from Rob was helpful. Did discover some codes were being thrown.

# Replaced MAP sensor, O2 sensor, and water temp sensor to address the codes captured from the ECU.

# Replaced gas cap. Ran a bottle of pass4sure through. Improved results, but still failed.

HC Result FAIL
HC Grams/Mile 1.95 HC Std 1.60

CO Result PASS
CO Grams/Mile 18.24 CO Std 20.00

NOx Result FAIL
NOx Grams/Mile 7.21 NOx Std 3.00

# Replaced catalytic converter, spark plugs, wires, distributor cap, and rotor.
Resulted in passing emissions with flying colors.

HC Result PASS
HC Grams/Mile 0.13 HC Std 1.60

CO Result PASS
CO Grams/Mile 2.74 CO Std 20.00

NOx Result PASS
NOx Grams/Mile 1.03 NOx Std 3.00
 
Glad to hear you passed! Way to stick with it, those Cat's can be expensive but they reduce most of the vapors quickly. I'm glad you didn't have the major trouble I did and were able to take care of it quickly.
 
I have no idea why type/brand of cat that was installed. Assuming a generic/universal one.

I had a local shop do the work, as I can't weld.
http://www.titanmufflers.com/index.html

They were quick, cheap, and open on Saturday when I needed them. English was a 2nd language there, but had a good experience :)
 
Back
Top