1990 2VZ-FE fails Smog Test

[monito]

Specs: 1990 Toyota Camry V6LE
Engine: 2VZ-FE
Auto Transmission


ASM Emission Test Results

CO2% O2% HC (PPM) CO (%)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS
15mph 1915 13.95 1.34 112 31 12 0.72 0.10 0.02

NO (PPM)
MAX AVE MEAS Results
778 237 967 Fail

CO2% O2% HC (PPM) CO (%)
Test RPM MEAS MEAS MAX AVE MEAS MAX AVE MEAS
25mph 1878 13.80 1.50 86 20 8 0.60 0.09 0.01

NO (PPM)
MAX AVE MEAS Results
717 199 714 Pass

MAX = Maximum Allowable Emissions
AVE = Average Emmissions for Passing Vehicles
MEAS = Amount Measured


Hello all! I took my vehicle in this morning for a smog test, and it failed the NOx ASM Emissions Test Results.

What would cause a vehicle to fail NOx emissions, and what are possible repairs that need to be done for my vehicle to pass its smog test?

Thanks in Advance,
~Ronaldo

[blu_91_cam]

Oh man we a a 2vz that failed ended up needing to replace the cat after that the car passed with flying colors. Not too sure if this is the same problem with yours. The guy who I went to to have the smog test done was also a muffler shop so.....

[Doctor J]

Beause the HC and CO readings even below average I assume that the cats are fine.
You need to check following items of your car's EGR system:
EGR vacuum modulator: must HOLD THE VACUUM if it applied to the big tube at the bottom of it
all vacuum lines
EGR to intake plenum port connection, as carbon tends to build up there;
BVSV
Hope this helps

[Kep]

^+1

I tend to be suspicious of a dirty / clogged EGR valve but the others would also result in the higher NOX. If you plan to clean this you may want to consider cleaning the EGR valve, the EGR Modulator, and the hoses connecting the two. But heck, while you're at it pull the throttle body, clean it and clean the IAC valve just below it. They all probably need the attention.

Kep

[monito]

How would i go about cleaning out the EGR vacuum modulator?

I've got EGR valve out of the car now, and Deep Creep is soaking up it's insides.
I used a couple of picks to scrape out some of the carbon build up in side the valves and some of the stems.

[Doctor J]

The vacuum modulator fails if the backpressure diaphragm ruptures (not able to hold vacuum) and it replaced after that.

[monito]

you know what doc?

You told me this about a year ago, and i didn't bother looking at the diaphragm. More like, i didn't understand what you were sayin. :P

[monito]

Work done:
Removed and cleaned EGR Valve.
Removed and cleaned EGR Temp Sensor.
Purchased and installed new EGR Vacuum Modulator.

Result:
My camry passes Smog Test! ^_^

Thanks again everyone for all your help!!! Thanks to TN, i once again saved a couple hundred dollars on repairs.

~Ronaldo

For the curious: NOx measured 301@15mph and 221@25mph.

[1mzEs250]

I had the same problem for weeks going back & forth. After I cleaned the egr valve,and changed all the hose that connect to the egr, and putting in a new egr vacuum solenoid it finally did the trick. So check the whole egr valve system and see if that works,if not then I don't know what the problem is.

[1mzEs250]

Change all your egr hoses!!!