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Upcoming smog test, barely passed NO last time, advice?

M

MachineMan

NAXJA Forum User
Location
San Jose, CA
Its time to smog my 1990 Renix again. Last time I barely passed the NO emissions so I might fail this time. Any tips on reducing NO?

Last time results:
15mph, 1720rpm, NO=1005ppm (Fail limit is 1015) Almost failed !!
25mph, 1698rpm, NO=310ppm (Fail limit is 875)

Thanks,
 
O2 Sensor and cataletic converter are a must have. I think u can do them both for 200 bucks. Maybe even a Tps sensor. Then all the normal things. Toon-up, fuel injector cleaner, air filter high octane gas. Then right before u go smog, blast down the freeway at 80 for a mile or 2 to let the Cat get nice and hot.
 
Pre-CA smog maintenance:

Every 2 years you gotta pass smog in CA, so I always use that as an excuse to do some needed maintenance on the ol' XJ.

1.) Tune-up: Plugs, Cap, rotor, wires, new 02 sensor (yup, $100 total every 2 years).
2.) Check all vacuum lines and connections. REPLACE, not repair, any questionable lines, elbows, fittings. $ ??.00
3.) Check the CAT for proper operation (even if you have to take it to a muffler shop) if it's bad, replace it.
4.) New Coolant Temp Sensor (the one under the manifold in the block, again $25 every 2 years)
4.) BRAND NEW gas cap. $11.00
5.) Can of G2P $4.99
6.) Injector cleaner treatment. $3.99
7.) Brand new oil change. $30.00

My 90 failed miserably 5-6 years ago. I did all this to it and it passed with FLYING colors, and has ever since. Mileage still around 18-20
 
ParadiseXJ said:
Pre-CA smog maintenance:

Every 2 years you gotta pass smog in CA, so I always use that as an excuse to do some needed maintenance on the ol' XJ.

1.) Tune-up: Plugs, Cap, rotor, wires, new 02 sensor (yup, $100 total every 2 years).
2.) Check all vacuum lines and connections. REPLACE, not repair, any questionable lines, elbows, fittings. $ ??.00
3.) Check the CAT for proper operation (even if you have to take it to a muffler shop) if it's bad, replace it.
4.) New Coolant Temp Sensor (the one under the manifold in the block, again $25 every 2 years)
4.) BRAND NEW gas cap. $11.00
5.) Can of G2P $4.99
6.) Injector cleaner treatment. $3.99
7.) Brand new oil change. $30.00

My 90 failed miserably 5-6 years ago. I did all this to it and it passed with FLYING colors, and has ever since. Mileage still around 18-20
Click to expand...

Do you run thru the whole gas tank with the G2P first, or put it in the tank and head to the smog station?
 
Blaine B. said:
18-12 highway???
Click to expand...

18-20 overall. Since I live in a small town, I don't do much "city" driving as the whole place is surrounded by "highways" and dirt. I do alot of hilly dirt driving, and alot of flat highway @ 65-70.

MachineMan said:
Do you run thru the whole gas tank with the G2P first, or put it in the tank and head to the smog station?
Click to expand...

The instructions on the can say to fill the tank.
Run a full tank, fill again with new gas, then smog.

I don't suppose that the tank has to be absolutely full, that's just what the instructions say. I can't say exactly which one of those maintenance issues works best but I'd fix the majors like vaccum, ignition and exhaust before I'd rely on G2P to cover all the non-maintained or poorly working systems. If you're running rich, you're running rich, so a working 02 and CTS should correct that. If you're not burning up unburned fuel the CAT should fix that.

...and the guy at the "Gross Polluter" station told me to get a NEW gas cap every 2 years regardless.
 
i failed AZ emissions with high nox. a sea foam treatment brought both the nox and carbon emissions down considerably. just barely failed at that point. a new none craced headder, new O2 sensor and new cat had me passing with flying colors
 
New cat worked for me. What does the o2 sensor help with?
 
they wear out over time an i have heard that they go out faster with a cracked exhaust. it helps keep everything in line so that you pass emissions. and keeping everything within perameters avoids your cat from dieing early.
 
RENIX? Possible causes:

Failed/failing catalytic converter.
Fuel delivery issue (going lean) due to failed/failing HEGO sensor, MAP sensor, or IAT sensor.
Fuel delivery issue (going lean) due to clogged fuel injector(s)
Failed/failing EGR valve (although my 87 actually ran cleaner with the thing not working than when I replaced it...)
 
I sea-foamed and then changed the oil in my 90 before I smogged it a couple weeks ago and it passed with no problem. It has 216K and it smoked for about a half an hour after sea-foaming it.
 
I have heard you let the tank get down to a 1/4, then pour in 2 cans of "Heet" gas de-icer. The alcohol content burns much cleaner.
Maybe a half tank of E-85 would do the same thing.

Or, you could fix it.
 
Blaine B. said:
EGR's are a big disgusting mess anyway. Who would want to recirculate your own farts through your nose?
Click to expand...

Yah. I'd rather run a water/MeOH or water/EtOH fogger, but CA won't let me do something that would actually work and not crap things up because it's not OEM.

(Nevermind that it would work better and keep the engine cleaner...)
 
5-90 said:
Yah. I'd rather run a water/MeOH or water/EtOH fogger, but CA won't let me do something that would actually work and not crap things up because it's not OEM.

(Nevermind that it would work better and keep the engine cleaner...)
Click to expand...


gotta love kalifornia huh, boy I can't wait to take mine to the smog nazis next month :wierd:
 
FoMoCo said:
gotta love kalifornia huh, boy I can't wait to take mine to the smog nazis next month :wierd:
Click to expand...

Yah. I've been going roundy-rounds with CARB for years over this...

And now they've fixed the cutoff for "no smog check needed," instead of the rolling 30-year cutoff. Bastids.

I still need to get a pick-em-up truck. My preferences (in order)
1) Pre-Smog J-truck
2) MJ (I already know what colour the wires are. 4.0L/5-speed preferred.)
3) Pre-Smog Dodge.
 
I'm also in So. Cal. with a high NOX 1989 "Gross Polluter". I'm going to try to get a few of my tax $$ back and let the state fix the Jeep.
IF you get a G.P. Fail you have the option of paying the first $100- toward repairs and have the state pay ". . up to $500- toward the cost of repairs to pass a Smog Check."
You need to get pre-approved and go to the proper repair facility. I already replaced the plugs, rotor, wires, run Sea Foam, etc., but it would be nice to have someone else some work!
I'm thinking, EGR, TPS, Cat., oxygen sensor, and maybe a few exhaust related things like the broken/missing lower rear manifold stud in the block, intake/exhaust gasket and maybe even motor mounts, because exhaust system flex could cause system leaks.
OR, you can get $1000- to "retire" your Gross Polluter. If you read how little is required to still be attached to the "heep" it might be a good time to swap parts and upgrade.
CA web site; http//:DriveHealthy.com
 
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