Smog Polution check failure

Hi, I have 71k miles on my 94 Metro XFI standard model except for AC. I use the car to communte 2150 miles from San Diego Ca to Fox Lake Ill and on 1000 camping trips to Cabo and LaPaz Mexico. The engine has always been kept in top shape and runs accross the US at 56 mpg 75mph uses no oil. I love the car allows me to go places without a furry of gas bills chasing me back home.

I took the car in for a State of California Smog check. It failed only the NO(PPM) portion of the test. Max was 753 my XFI came in 999 on the high and low speed portion of the test. I researched the problem and ran the onboard diagnostic. Research pointed to EGR valve and Diagnostic said O2 sensor was bad. I checked EGR seemed free and replaced O2 sensor. It failed second Smog Check results were same as first so I missed problem totally.

If anyone has had this problem Id sure like to know how they corrected it, Im stumped. The polution tech said it is a cronic problem with the 1.0L. I find hard to believe as the average NO(PPM) measured state wide is only 150 and mine was 999 so seems like a part failure somewhere?? Thanks for any suggestions! :frown:

My 1.0 liter Geo Metro failed the new smog test as a gross polluter. Its strange how it could get 50 mpg and still fail. I don't want to get rid of the car, but its not worth paying $100s to get it up to passing. Any suggestions?

My 1.0 liter Geo Metro failed the new smog test as a gross polluter. Its strange how it could get 50 mpg and still fail. I don't want to get rid of the car, but its not worth paying $100s to get it up to passing. Any suggestions?


:banghead: First step is to find where you failed the state polution check. Next identify the componets in the 1.0L that control the polutants that made it fail. Also be careful in your repair or replace decision if you compare fuel costs to a 20 mpg car savings justify putting money into the car. It just politics as usual a SUV put out more pollution passing than my 1.0L did failing. :screwy: Good Luck

In the first place, mileage has little to do with emissions...usually. In many cases you can tune cars to get better MPG but the emissions will go all to hell. You would think that it would balance out somewhere (less emissions but more gas to get there ???). Anyway, I digress. The first thing to do is check your ignition timing as NoX is caused by heat. The timing being advanced can up performance and mileage, but will cause you to fail the smog check, although if the timing were way out you would have failed the initial inspection before they ran the dyno. Next is the EGR. Although the valve may be free, the vaccum lines to it may not be. Also the passages under the valve might be clogged. To check, operate the valve by hand with the engine at idle. When you open it, it should sputter and possibly die. This will confirm that the passages are at least open. The car is almost 10 years old, so it may be time for a new catalytic converter too... Oh, also any vaccum leak can cause the car to run lean also creating heat.
Good luck!

try one of those slick 50 or the like things you add to your gas and see if you pass(god im glad i live in minnasota

MANAGE YOUR HEAT!!! MANAGE YOUR HEAT!!! MANAGE YOUR HEAT!!! MANAGE YOUR HEAT!!!

MANAGE YOUR HEAT GEO METRO FANS!!!


The best thing you can do for the Geo Metro is install a switch to the fan. The Geo Metro has heat problems when sitting in traffic or idling in summer. The result is a progressively weaker engine and increasingly higher HC levels, ultimately leading to failed smog checks.
The temperature level programmed in the ECM that switches on the fan is so high it damages the engine during sensitive use, so override the computer by installing a switch and using it when in traffic or even around town in summertime. Just find a power source and run it through the switch to the fan coupler.
It is important that you are vigilant with the switch. If you are a start-and-go type of driver who would be apt to neglect the switch I would recommend the following two heat treatments as well:


Run the heater constantly, including in the summer.
If you put the heater on defrost with the windows rolled down the heat goes out the corner of the window. You won't even know it is on. This is crucial for managing heat, important especially at freeway speeds which could damage the fan motor if on, since it spins the opposite direction.


180 degree thermostat.
Install a 180 degree thermostat. It doesn't affect performance and gives an additional measure of protection.


Removing the protective substitute 'plate' from non-A/C metros will
also help cool the engine off, since all that air is now blowing into
the engine compartment. This unfortunately could negatively affect mileage.
There's a chance some moisture may also enter, but since the condenser allowed moisture and air through anyway, it should also be safe to keep the plate off a NON-A/C metro.


A fellow on eBay sells something he calls a "Oil Filter Cooler Collar", which is a heat sink for the oil filter. It requires modification for proper fit, but I swear by it. JCWhitney sells one that needs no modification for three times the price.

Put some octane booster in your tank before the test and run at least 50 miles to insure it gets mixed properly, this will allow the fule to burn cleaner for the test. Make sure you have over 1/2 tank of gas durring the test.
This works for the Ca test.

Speaking of the CA test when i took my 90 metro there in 95 the garage attendant was funny...

He said if im attempting to commit suicide by running a hose in the car, im gonna need several hours if not days because the car burned so clean...

Speaking of the CA test when i took my 90 metro there in 95 the garage attendant was funny...

He said if im attempting to commit suicide by running a hose in the car, im gonna need several hours if not days because the car burned so clean...


Yeffer Ive commuted between Chicago and San Diego for years in many different cars and airlines. The 1.0L has to be one of the best fuel efficient, clean burning and low blowby engines built for continuous long distance high speed driving in extreme cold or heat. It does burn very clean in fact one of the cleanest burning engines Ive owned. The problem with the small engines including Honda and Toyotas is they burn hot in the cylinder so the NxO rating is high. Thanks to the help from the Geo wizards on the forum I adjusted timing and added an octain boost and shes happlilly running the interstates now with a new Pheonix oversize AC condensor and dual evaporators so she cools down like a refrigerator at 125 degrees on the Mojave. I also added VHF/UHF Echolink and IRLP so I get free world wide communications with my handy talky, Magellan GPS, Microsoft GPS, 40 watt CB and SprintPCS wireless internet so I can scan weather ahead or call ahead with Echolink as a base transceiver over my laptop. Next is a full light weight roll cage. I like this little fun car wouldnt part with my cross country XFI for anything.