viking443

Hi all- new register on the forum but long-time user of the info to help replace lots of stuff on my '99 Cherokee Sport. You guys are great. Now, moved to CA and I am trying to pass the CA Smog Test and need help. Bought it used in 2010 and will have to sell in Nevada if I can't figure this out. Here's the details...

- Car originally from East Coast (Delaware) so not to specs with CA emissions control system
- Got to CA, had a smog test (yes, should have done a pre-test), and failed big time for NOx. Here were the read-outs for the 25 mph test:
CO2- 14.10%
O2- .68%
HC- 16ppm
CO- 0.00%
NO- 1623ppm
- Replaced the cat converter with the CARB-approved OEM model, 3-way cat, and replaced the downstream O2 sensor at the same time. Also changed spark plugs. Engine temp is OK by the gauge.
- Brought the NOx levels down to 1000ppm with a new cat. but still fails by about 400ppm
- Got 'er into a reputable shop, which looked over for 3 days. Checked and swapped out upstream O2 sensor and other sensors to see if results improved. nega-tory. No bad readouts. Shop conclusion- engine works great.
- Shop did mention that header pipe was not "original", and they called Jeep dealer to confirm that it should have an upstream cat converter... I take this to be the CA emissions mods?

So now, I'm faced with trying to get a Cherokee not made to run in CA up to CA specs. I have searched and found hints that there are 2 or 3 cats on the CA-equipped models- and more O2 sensors? What's the best way to upgrade to make it pass? I've talked to other folks that just put 2 cats in series on other Jeeps, but don't know about this.

No, I can't move from CA. And yes, before the next smog test, I will do the ritual oil change, whiz-bang stuff.

Thanks for all any help!

EastBeast

Idk about cali models but my 2000 has 3 cats. I have a stock 2 piece exhaust manifold so 3 cylinders are each picked up by 2 cats right up by the engine. Each of these forward cats has an upstream and downstream o2 sensor. They Y together and run down to a rear cat and muffler. My rear cat has no o2 sensors. As far as I know this was on 2000/01 Cherokees and the 99's had a manifold that just pipes back to 1 rear cat with sensors. Your cat is new so can most likely rule that out but there are other things that can contribute to the high NOx reading. NOx is produced in the combustion chamber at like 2400? degrees. Improper air/fuel mix so it could be running hot. Timing could be off, bad egr in some way. Idk how many miles or the health of your rig but it's 12 years old so may just need a good overhaul and she'll be fine. Thank god I moved from cali!

DFlintstone

My CA Smog License expired in 81, likely you will get better help from the "Wizards" here! The EGR valve's function is to reduce NOx. I would think first you would need to verify that you do indeed have one! With the header I would wonder. Welcome to CA....I remember when the smog was so bad it hurt to inhale. All this junk actually worked.

.................................................. ................V.. "whoops" and "I told you so!" ..V

viking443

Thanks much for the replies. Engine has 130k on it. A tune-up is good, but it was checked out already... I'm confused though- based on some trusty-friend Google searches, I was thinking that later model year Cherokees didn't have an EGR valve?

EastBeast

Yes no egr. Sorry I was tired. But there are a lot of little things that can cause this and you are close to passing so don't expect it to be a major problem, it's going to be something harder to detect probably. Vacuum leak, leaky manifold, carbon build-up in the engine. Timing could be off just a bit, etc. You can def scrutinize the MAP sensor. You need to verify that compression,timing, vacuum, fuel pressure are definitely normal. I would take it to a really competent jeep dealership or specialist at this point and skip general repair shops. You are going to need someone who really knows cherokees. Does cali still have something in effect that limits how much money you have to spend in any certain timeframe on smog repairs? The jeep was warmed up and ready to go for the test too right? Cold jeep is going to give higher readings. And you use 87 octane? Is your thermostat correct ?

89MtnXJ

I don't know where you are in CA but if you're anywhere near San Berardino Mtns call twin peaks auto repair. They are absolute magicians, after I found them I refuse to go anywhere else.

viking443

Thanks much. Jeep was warmed up and using 87 octane at test time. Had it diagnosed at the Jeep dealership and they say it's a cracked exhaust manifold. Also said that the upstream O2 sensor is biased lean but that was checked before, so I'm not sure about that one. Other shop I had it at switched out both the MAP sensor and the upstream O2 sensor and only saw a drop of about 150 ppm. I'll probably just replace the O2 sensor anyway.

I've seen mixed thoughts on whether a leaky manifold will cause higher NOx?

There is a waiver if you take it to particular shops. Almost more hassle than it's worth.

Coolchange

Throw about a 10% load of methanol in the tank.

highmileage

How long have you been in cali? My brother-in law bought a toyota tundra while in Missouri and it barely passed smog in cali (his nox was high also). when he took it in for his next smog 2 years later it passed like it was brand new. smog tech said it was most likely due to the computer and engine adjusting to smog fuel.

DFlintstone

I keep thinking about coolchanges thought. NOx forms at high temps. Methanol/Ethanol burns cooler. Better to get to the core of the problem of course, an interesting thought though.

** I'd put the spendy fuel in it, not 87.

KD3NE

Can't help with the tech aspect, but a little sarcastic humor perhaps ...

Can you move back east?

Sorry I could not resist. I have some friends who moved from the east coast to CA and had issues that arose after they got there and the got their employer to relocate them to a friendlier state.

viking443

Final update- finally passed smog. Here was the sum of fixes:

- new 3-way cat
- 2 new O2 sensors
- oil change
- sea foam- 1/3 can in the brake booster, 2/3 can in the gas tank. Then another 2/3 can in the gas tank with a full tank of gas. Jeepy was smogged with some Sea Foam in the gas

The local Stealership told me that I needed a new exhaust manifold to pass. It didn't totally make sense to me, since my HC and CO were low to nil, and NOx was way high. Also recommended a fuel injector cleaning (Sea Foam- cheaper option.) I'm not saying that it isn't good to replace a cracked manifold, but it was a really expensive fix that may or may not have done anything.

So, in the end, I'm convinced that many techs don't really know how to diagnose the smog check readings. Most just try something, see what happens, and try again. So, start with the cheap options first. In the end, I am pretty sure I needed a new cat and O2 sensors. Past that, it was all engine clean up.

One more thing. Despite all the aggravation the great state of CA caused here, I did talk to a tech expert at the Department of Consumer Affairs in charge of smog stuff. He was able to take a look at my readings over the phone, and was skeptical of the manifold fix. He pointed me to fuel systems (although he said to maybe change the fuel filter, which I didn't, on account of it bein in da tank.)

413maxwedge

nice

ol'DixieJeep

I would have moved...

Mmurdock

It's a little late now, but doesn't CA have an rule where if the cost of emission repairs exceeds a certain amount you can pay a fee and have the vehicle exempted?

I may be confusing this with WA emissions law.

I spent 4-years in Cali while I was in the Navy and would never live there again. Visit yes, live no. The Navy required us to have our vehicles emissions tested in order to get a base decal. I had bought my CA emission CJ in WA several years earlier and had made significant modifications to the engine (cam, Weber carb, custom tube header, no muffler). When my previous decal of WA origin expired my only real option was to get 90-day temporary passes for about a year until I transferred back to WA. I was not about to return my engine to stock.

I believe a group of military members sued CA over the requirement to have their vehicles smogged (since we don't have a choice in where the military sends us) just after I left. From what I understand CA lost and had to make refunds to military members who had been charged a $300 fee to exempt non-CA emissions equipped vehicles.

I also understand sometime in the early '90's CA tried to force non-resident military members stationed there to pay state income tax. That brilliant idea didn't last long.

Back to emissions: WA recently announced it would eliminate it's emissions testing progam over the next couple years. Their reasoning: Today's cars have incredibly clean emissions and the percetage of older unclean cars is getting smaller everyday. Oh, and the state is broke and it costs too much money to run the emissions testing program anyway.