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Emissions

4x4JeePmaNthINg

NAXJA Forum User
Location
Colorado
Hey all,

I'm out of my wheelhouse for this topic.

After the lady broke their emissions roller, they moved my jeep to the machine I guess they should have used for the tire size. Anywho, I failed emissions today and this has been the first time I have ever had an issue. This is also the first time my vehicle was tested after my factory CAT was stolen and I slapped a cheapo ( non CARB compliant) to get buy on.

I dont want to assume anything so Ill ask the wiser here if I may. I have failed for high HC- (.97), the limit is .8 GPM and NOx- (5.1) and the limit is 1.5 GPM.
My jeep is a 99, upstream sensor is NGk (maybe 5 years old), down stream is bosch (its been there quite some time). I have no CEL.

Is it safe to say its the catalytic converter or would you suspect something else.


Thank you for your insight
 
Hang on, they actually do a dynamometer test on CO on those and don't just plug into the computer and look for emissions codes? Interesting. Also, if I'm reading your post right, they didn't account properly for your tires and broke one of their machines trying to test it? That's striking me as kinda funny, though I hope they don't try to stick you with the bill for fixing it.

I'm no expert, but couple thoughts: Air filter need replacement? Have you cleaned injectors/throttle body recently/ever? Do you know what the results were the last time it passed (and when that was), for comparison?
 
Hang on, they actually do a dynamometer test on CO on those and don't just plug into the computer and look for emissions codes? Interesting. Also, if I'm reading your post right, they didn't account properly for your tires and broke one of their machines trying to test it? That's striking me as kinda funny, though I hope they don't try to stick you with the bill for fixing it.

I'm no expert, but couple thoughts: Air filter need replacement? Have you cleaned injectors/throttle body recently/ever? Do you know what the results were the last time it passed (and when that was), for comparison?

Hey Rob,

Yes, they do vehicles on a dyno and measure our emissions in CO. They did not give me any guff on the dyno that was broken, employee error I suppose. Every time I have ever been there, they have used that size dyno and yes the lady broke something in the roller and blew a fuse. Something shot sparks hahaha, I thought it was funny as long as it wasn't my jeep, I thought something grenaded as loud as it was, and thats saying a lot after the roar the MTRs were giving out.

I can replace the air filter as I do my next oil change, it certainly couldn't hurt. The throttle body has not been cleaned for a while, I suppose ill add that to the list for good measure. My injectors are 4 hole and I haven't specifically run any techron or seafoam type cleaners through lately. I had read that gasoline these days pretty much has all that stuff added into it, in less concentration anyway.

On a side note: I have been running 85 octane for a good while lately, I'm at about 5500ft of elevation and the jeep doesn't seem to complain about it.

I don't believe I still have the old test results, damn thief probably took those while looting my jeep when they stole the cat. I do recall studying the test results last time I ran emissions and I wasn't even close to failing anything. We test every two years here and the only change that I have made to the jeep is the cheap fix cat that I put on, and 85 gas pretty much all summer. Oh and I put a muffler back on at the same time, that shouldn't cause an issue. I can post up my current print out once I find a good image host to link it here.
 
QC8ucz8


rM1iWoS
 
Well, it's hard to say. I generally have issues passing smog here in CA with my '88 so I understand the frustration.

A big thing to consider is to make sure you drive around enough prior to the inspection to ensure the cat is fully heated. One time, I had to wait for my test and it cooled enough to fail. The tester then let it run on the dyno for about 10 min until it got back to full temp. It still failed but NOx was fine.

A high HC indicates a rich condition. High NOx indicates high combustion temps.

Nothing wrong with an oil/filter change, de-carbonize, and a little seafoam.

If you have one or access to one, use a OBD scanner with live data so you can verify closed loop and review O2 sensor data and fuel trims.

If the CAT's bad, looks like you'll need a CARB one now.

https://cdphe.colorado.gov/aftermarket-catalytic-converters

"As of January 1, 2021, all sales or installations of aftermarket catalytic converters for any model year vehicle in Colorado must comply with Air Quality Control Commission Regulation Number 20. Either replacement catalytic converters must be original equipment from the manufacturer (OEM), or a new aftermarket catalytic converter certified as meeting California’s Air Resources Board (CARB) emissions standards.

The California Air Resources Board issues Executive Orders that exempt specific catalytic converters from anti-tampering regulations and laws. This exemption allows "exempted" (approved) catalytic converters to be used in California and in states that have adopted regulations in Title 13, California Code of Regulations, Section 2222. "
 
Well, it's hard to say. I generally have issues passing smog here in CA with my '88 so I understand the frustration.

A big thing to consider is to make sure you drive around enough prior to the inspection to ensure the cat is fully heated. One time, I had to wait for my test and it cooled enough to fail. The tester then let it run on the dyno for about 10 min until it got back to full temp. It still failed but NOx was fine.
I did have about a 20 min highway drive until I got to the facility, they pulled the jeep straight over to the other bay after 6 pulls on the dyno they broke. I hope it was fairly warmed up by then

A high HC indicates a rich condition. High NOx indicates high combustion temps.
Would this be seen if you have the common cherokee header cracked?

Nothing wrong with an oil/filter change, de-carbonize, and a little seafoam.

If you have one or access to one, use a OBD scanner with live data so you can verify closed loop and review O2 sensor data and fuel trims.

If the CAT's bad, looks like you'll need a CARB one now.

I dont know if the cat is bad necesarilly, or just so cheap that it doesnt really do what its supposed to. It was 50$ and is fairly small compared to the stock cat. Its a far cry from CARB compliant.

https://cdphe.colorado.gov/aftermarket-catalytic-converters

"As of January 1, 2021, all sales or installations of aftermarket catalytic converters for any model year vehicle in Colorado must comply with Air Quality Control Commission Regulation Number 20. Either replacement catalytic converters must be original equipment from the manufacturer (OEM), or a new aftermarket catalytic converter certified as meeting California’s Air Resources Board (CARB) emissions standards.

The California Air Resources Board issues Executive Orders that exempt specific catalytic converters from anti-tampering regulations and laws. This exemption allows "exempted" (approved) catalytic converters to be used in California and in states that have adopted regulations in Title 13, California Code of Regulations, Section 2222. "
 
Yeah, that looks like a chinese made piece of junk. Bunch of reviews said the honeycomb failed very quickly. The lack of a heat shield is a clue that it doesn't get hot enough to work. You've been complaining about a lack of power, and I suspect putting that tiny cat on there didn't help.

Some of the O2 sensor numbers look weird to me. The S2 downstream sensor showing a lower voltage (more O2) than upstream might imply you have an exhaust leak or a bad sensor. A bad injector not flowing the same as the others will throw things out of whack as well.

5-speed stick? I wonder if your TPS is bad and signaling WOT causing the computer to go open loop while your shifting? The NOx bouncing around once it's above 50 looks weird too.
 
Yeah, that looks like a chinese made piece of junk. Bunch of reviews said the honeycomb failed very quickly. The lack of a heat shield is a clue that it doesn't get hot enough to work. You've been complaining about a lack of power, and I suspect putting that tiny cat on there didn't help.
no power issues, but that sucker got hot enough to melt carpet pulling mountain passes this summer. Is there an appropriate temperature I can check for with an IR thermometer?

Some of the O2 sensor numbers look weird to me. The S2 downstream sensor showing a lower voltage (more O2) than upstream might imply you have an exhaust leak or a bad sensor. A bad injector not flowing the same as the others will throw things out of whack as well.

5-speed stick? automatic I wonder if your TPS is bad and signaling WOT causing the computer to go open loop while your shifting? As long as the sweep is clean on an analog meter, it should be good right? The NOx bouncing around once it's above 50 looks weird too.

Amazon dropped off a scanner, once its plugged in it said it didnt support live data on my vehicle. HA, its supposed to be a good obdii scanner for basic codes and live readings. I have a different one coming in the morning so I should be able to see something on the O2 sensors and fuel trims iirc. The exhaust manifold could certainly have a crack, but would it spike both the HC and NOX? A youtuber (https://www.youtube.com/watch?v=4st6Hf5-nJ4) his video mentions a faulty catalytic converter can have both of these symptoms.
 
Haha that's a good question, the way things are going not long. Unfortunately I'm doing the emissions test for registration due in a month. I have learned CO, for whatever ingenious reason, will only allow you to do drive by testing up to two months prior to your registrations due date. I may have stood more of a chance with those as an option. I had an old boss that would rev the piss out of the work truck going by those things haha.

Tonight I have also found that the header has a pretty damn big crack on it, right along a weld to the condensing portion. This is pretty unfortunate considering its my replacement to the first banks that was on here. Should've just bought a new baffled one like I got the first time I replaced the oem manifold.

I'm assuming the cracked header and the crummy cat are both playing a part in the testing results. Now if the new scanner works for live data, ill see what the O2 sensors are reading. I imagine there would be a good bit of soot on the upstream sensor as well, hopefully its not faulty.
 
well I have been messing with the two scanners topdon artidag500 & blue driver, they arent too fancy. The topdon gives a bit more things to monitor and seems to list fuel trims as ADAP mem factor, adap long term, adap short term? . They have most of the same features and graph a bit differently, topdon does show ckp, cmp count, throttle voltage and value, calc volts. I have no idea what half of it means.

What I can seem to tell is that the system does indeed go into and stay into closed loop while idle/driving. The O2 sensors are fluctuating in what seems to be a normal way, no reading is frozen.

I'm about to tear into replacing the header for now.
 
https://imgur.com/a/vpdGvE1

I did not notice a difference driving after putting the new one on. There is one bolt that is hellllllllll to get started, otherwise not bad for the 4th go of it.

New air filter is in and I ran some seafoam through the TB, 1/3 in the tank and 1/3 through the throttle body. I must have done something wrong adding it through the TB because it didn't smoke much and there is certainly carbon build up.

Maybe some better gas will help breakup some gunk and perform a little better at the emissions place.
 
In theory, a crack in the exhaust manifold will tell the (upstream) O2 sensor that there is too much oxygen and it will richen up the fuel mixture. That might result in a higher hydrocarbon reading. So hopefully, replacing that header will help you out.


I also use 85 octane but I'm not picky on the brand.



For reference, here are my last two Colorado emissions test results. 1997 4.0 5-speed:
2021: HC 0.5619/1.2; CO 5.9245/15; NOx 1.2629/3
2019: HC 0.1759/1.2; CO 3.0601/15; NOx 0.7839/3

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Are you talking about ethanol-free gasoline? The studies I've read show fuel with a small blend of ethanol (10% is typically what is sold) actually results in lower levels of hydrocarbon and NOx emissions.
 
Yes that is what I was thinking of. There is what's labeled 87 octane clear gas ethanol free at the station I'm thinking of. I wasn't sure if ethanol helped or worsened depending on the grade.
 
Well round two failed, I kind of thought it would, but figured it worth the shot since it was free. I just put in regular 87octane.

The HC did come down from .98 to .83, tolerance is .8gpm.
Nox stayed pretty much Identical at 5.06 from the previous 5.1, tolerance was 1.5gpm.


Ill check spark plugs, cap/rotor tomorrow just for good measure, oil change otw soon to.

Is there anything else I should be checking without having some special equipment?
 
High NOx is indicative of high combustion temperatures. How is your cooling system?


Otherwise, unfortunately, a new catalytic converter might be the best solution. Because of your previous exhaust leak, running rich might have put too much strain on the cheapo amazon cat and caused it to fail prematurely.
 
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