Failed another smog check

Well, failed the smog check today, even got gross polluter status from the state. Anyway, here are the values from the test:

Note: California's smog test is run on a dyno, hence the speed ratings.

%CO2 %O2 | HC (PPM)
Spd RPM Meas Meas | MAX GP Meas
15 1709 12.60 0.15 | 123 310 225
25 725 12.40 0.14 | 103 260 228

CO (%)
MAX GP Meas
0.73 2.03 3.25
0.93 2.23 3.52

NO (PPM)
MAX GP Meas
1015 1800 1211
875 1600 1057
Legond: GP = Gross Polluter Limit MAX = Max Allowed Meas = Measured Amount

Background Info:
1989 4.0 appx. 230k AW4
Stock engine and fuel system, stock air intake.

Cat is most likely hosed, I was spitting out black smoke for a few weeks (anybody remember me in Moab? ), Looks like I will be replacing it.

New TPS adjusted to 83%, new Idle Control Valve (made things nice), new MAP, new CPS, new pickup coil/cam position sensor. EGR looks good (functioning diaphram).

Throttle body most likely needs to be taken apart and cleaned. Needs a good seafoam treatment.

Any other ideas, the above things that I was saying it needed are things that I'm going to do whether for the smog test or not.

Thanks,
Sequoia

GSequoia said:

even got gross polluter status from the state.

Click to expand...

They must have looked under your rig after it was parked and noticed all the leaks
Btw, did you go to the test with a somewhat cold engine or did you drive around a bit to warm things up?

Full operating tempature.

Could be a bad oxygen sensor.
If the engine seems to be running fine, I'd say it could be the oxygen sensor, catalytic converter or both.

MAP

Probably not O2, I forgot to mention that I replaced that not very long ago (five to seven thousand ago). I might get one tomorrow just in case if I get a good enough deal on it though.

When's the last time you did a complete tune-up (plugs, wires, cap, rotor, fuel filter, air filter, TB/intake cleaning)? Sounds like an inefficient burn and/or running very rich is a big part of the problem here, black smoke is usually fuel. Running rich may be caused by a bad O2 sensor, you'd have to hook up a pre-OBDII scan tool and watch the O2 sensor values to be sure though. It's not uncommon on Pre-OBDII vehicles to see an O2 sensor giving out-of-spec values to the computer, but the CEL remains off because it's still switching.

As for the cat...Get under the car, and punch the cat with your hand (do this while the car is cold, and don't break your hand in the process). If it rattles inside, it's shot and needs to be replaced. If it doesn't rattle, try addressing the above issues first. Converters are expensive, you want to be sure that's really the problem before spending big money on one.

Just from looking at the Nox readings, I would say that your cat is junk. This also explains the high O2 and HC readings as well. Do not rule out a bad O2 sensor, as well as the coolant sensor under the intake on the block. That one tells the ECU when the vehicle is at operating temp for emission adjustment. Check your air filter(probibly dirty), and change your engine oil as well. The readings remind me of the last time I gross poluted in 2000, expect to smog your jeep every year for the next 5 years....It may just happen...Good luck

Okay, the cat is on schedule for replacement, I'm sure it's thoroughly screwed as I said. Good thing I'm old Renix so I can get a cheap cat

CTS is fairly new.
Air Filter is clean - This is my smog check only intake (stock), so it never gets a chance to get dirty

There's somebody local here iwtha Renix scanner, gonna get in touch with him and hook it up.

By the way - AAA has a good price for smog check, was about $47 I think (with free retest withen 30 days). Not all locations have smog check service, the one here in Downtown L.A. does. Just an FYI.

Sequoia