I have a 5.0 TPI engine, everything stock. I am running well above (about 2-3 times) Nevada emissions limits (220 PPM for Hydrocarbons and 1.2% Carbon Monoxide). I was lucky and found a place that will retest me for free until I pass, however i think i'm going to run out of time and money before then. I have recently replaced spark plugs (NGK UR4 Spark Plugs, Stock heat range, gapped at .035) oxygen sensor EGR valve (it was throwing the code for that) Thermostat Coolant temp sensor I have cleaned out the intake plenum. I set the timing to 6 degrees, 12 degrees, 0 degrees. I checked the plug wires, rotor and cap, all look good. I even tried this stuff called "Guaranteed to Pass" and still failed. I replaced the catalytic converter last year when she wouldnt pass, and now im afraid that might be the problem, but if there are any suggestions please let me know because it is a pain to replace the cat con. The car runs great, no stalling, no sputtering, no backfiring, no SES lights. The only problem I have is the speedometer does not work, not sure why yet. There has to be something i'm missing. Thanks in advance.

Welcome aboard thirdgen.org.

High hydrocarbons are due to unburned or partially burned fuel. Usually a cylinder miss. You said you "checked" your wires, cap, & rotor - checked how? What did you find? How old are those parts? Have you done a compression check? Leaking exhaust valves will also do it.

High carbon monoxide is the result of a rich mixture. O2 sensor is a typical cause of that, but a leaking injector or high fuel pressure will also do that. If the leaking injector is on the passenger side, the O2 sensor won't see it and compensate, but the sniffer will see it.

Both of those conditions will lead to early catalytic converter failure.

I checked the wires, cap and rotors visually, and i replaced them about a year ago. The wires looked solid with no burns or anything, the cap looked shiny and new, and the rotor looked decent, not brand new but only minor burning. I might replace them just to see if it helps. I haven't done a compression check, that will be next on my list.
Is there any way to test the fuel injectors? I have been leaning towards this being the problem since it is running so rich.
and maybe i'll just suck it up and replace the catalytic converter again.
Thanks for the help, at least i have direction now.

When was the last time the oil was changed?

My RS has barely passed sniffer with 195 ppm only to come back the next year and give 12 ppm with clean oil, air filter etc.

Are the air filters clean?

Is the PVC system working correctly?

If the car is sucking a lot of oil via PVC sometimes that can push the PPM up.

The car also needs to be hot into order to pass the old sniffer test emissions. Hot engines tend to burn cleaner. What temp thermostat is in the car? If you've got a 160 in there and it should be a 180 that can hurt emissions testing.

Has your gas mileage decreased?

What sort of mpg does the car get?

Is your AIR pump working? This thing pumps extra air in at the exhaust manifold to help burn of excessive hydrocarbons.

Make sure the car is fully warmed up before it's tested. I'm mean really hot.

I was actually wondering if anyone has ever tried that Guaranteed to Pass and see if it actually worked and what they give you if it doesn't pass. I am thankful that my car is old enough that they don't put it on a sniffer for emissions. I removed everything, to include any code that the computer would use to spit out a code. I hope he can find the answer.

the oil is about 2 months old, so maybe an oil change will help. the air filters are clean and the pcv is good (it rattles when i shake it) but the intake plenum was coated with oil and nasty stuff, so maybe i should change the oil and pcv valve.

I drove around for at least half an hour on the free way and surface streets and the thermostat is 195, so i know the car is getting hot, the gauge isn't accurate all the time so i don't know how hot. and the speedometer is broken, which means the odometer doesnt work (hope emissions people dont care about that...) so i dont really know the mpg very accurately. I dont fill up any more often than usual though.
I'll try and find a way to test the AIR pump, it has probably never even been looked at.
I bought new o-rings for the injectors so thats my project tonight, maybe ill pick up some oil and see if i can pass tomorrow morning.
Thanks for the help, i'll keep you guys posted.

Let us know how the test goes.

If you don't mind post the actual values for the PPM and Carbon Mox for each of your emissions tests.

If stuff is really built up a de-carbon treatment might help.

What type of oil are you running?

Weight?

10w-30?

Dino or Synthetic?

Good Luck, I hope the car passes todays test.

sorry for the delay, the fuel injector o rings were a bigger project than i anticipated. they were pretty bad, dry and cracked. i changed the oil and pcv valve too. still failed. I was running about 350 ppm hydrocarbons and 4% CO at idle. They didn't even bother testing high speed. I put mobil pure synthetic 5w-30 and a bosch filter in the car. i cleaned the fuel injectors off with qtips and alcohol. The injectors didnt all match, and one looked pretty old, maybe an original. the rest of the injectors looked good. i don't know how much that matters. the car is still running very well and i dont understand why it wont pass. the only things i can think of are the AIR pump and catalytic converter. any thoughts and suggestions are appreciated.
Thanks again.

time for a new cat

if it was fully warmed up & in closed loop, your rich.
even with a bad cat 4% CO is high. thats where some of the HC is coming from.
what brand of O2 sensor did you get?
how warm does the motor get?
do you have a way to scan it?

the o2 sensor is bosch and the temperature gauge doesnt work all the time, it gets to 100 then drops. but i drove it for a half hour in the city in 110 degree las vegas, the engine was probably as hot as it was going to get. A new cat con might do it, but i replaced that a year ago and I havent checked the AIR pump yet. as for scanning it, i grounded the terminals under the dash and made the engine light flash. only code that came up was for the speedo not working, and thats obvious

If your at 350 ppm it sounds like your ppm has been reduced. The oil change probably helped. The 4% CO is really, high. I don't have any experince with getting that back into line. Like the others, I think the car is probably rich. If the CO comes down the PPM will probably drop into spec.

You mention the fuel injectors don't match.

How many different types of injectors are present?

Are you sure all of them are the correct size?

Can you test your fuel pressure and make sure it is in the correct range?

If a 28 or 30 pound injector(s) in there that could cause the rich issue and high ppm.

A cat shouldn't go bad in a year under normal circumstances.

Stock PROM?

My AIR pump is gone, but my cat is only a year old, yet I passed EASILY! The catdoesn't even have the AIR pump tube hooked up. Visually, "technically" I should fail. But my #s are LOW, LOW, LOW!

I had the car checked again today, just in the off chance it got better, and the PPM went up to 500 and CO% went to 5. this car seems to get worse and worse results.
The PROM was replaced about 2 years ago with a stock replacement, so its a good bet that its working correctly, although a performance chip might get better results
there were 3 types of injectors, 4 on one side were the same and three on the other side were another type with 1 odd one that looked stock. i havent checked the fuel pressure, that could be an issue. i am pretty sure the injectors are correct, even though the guy who owned the car before me probably put them in. this car passed emissions twice before with these injectors so if they are causing a problem theyre bad. I have been looking for a local shop that will check the injectors but nobody seems to do flow checking. i can't afford a whole new set...
I checked the AIR pump by taking off the rubber hoses and switching valve stuff that sits on top of a stiff tube coming directly out of the pump and revving the engine. the air flow increased with revving so i guess the pump is good. I'm going to check some more stuff with the AIR system, like the check valve and the tubes.
thanks again for the help

could my problem be my speedometer? I was reading this on tpiparts.net...
It is absolutely critical for the ecm's learn mode, timing retard, emissions, torque converter lockup (automatic lockup transmissions only), idle speed control, and to avoid stalling on deceleration.
I have talked to a dealership about needing this part, but the parts guy seemed to think I didn't have a vehicle speed sensor on my car. If the ECM thinks im at 0 all the time, maybe the emissions stuff doesnt work. although im at 0 when i get tested. any thoughts?

For future reference before you smog again, find a shop that will pre-test your car before it is hooked up to the DMV computer. I am not sure about states other than California, but here, if you are connected to the DMV and fail, you are labled a "gross polluter" and are in for problems just about forever. It`s easier to avoid the problems and correct them before being failed. I have been failed before because the clown doing the smog test input all wrong info for my car into the computer. Check your paperwork to make sure this did not happen to you.

yea, dont worry about that. this place is just pre testing me. i failed once officially but all the other times its not hooked up to the real testing server.

the speedometer not working could be part of the problem, if the ECM is seeing a good speed reading but the speedometer itself isn't working then no. if the ECM is not getting a good speed reading, then that needs to be fixed.

also, bosch O2 sensors seldom work properly in most GM vehicles. its not the the sensors are bad or poorly made, but more of a calibration problem on bosch's end. along with repairing the speedometer, i would get an A/C Delco O2 sensor, clear the ECM by disconnecting the battery for about a minute, then drive it for about an hour & try again.

sounds like a plan, i'll try to get a AC delco sensor and put it in tonight and test it tomorrow.

Don't mean to hi-jack the thread, but I'm kinda in the same pickle, except I failed CO as well as HC. Here's the results for my 89 TA:

Emissions / HC Hydrocarbons / CO Carbon Monoxide / NOx Oxides Of N...
--------------------------------------------------------------------------
Stand. Units / 0.8000 / 15.0000 / 2.0000
Grams/Mile Grams/Mile Grams/Mile
--------------------------------------------------------------------------
Reading: / 2.0813 / 34.2569 / 0.6791

The car drives fine, never really had any problems with it and it's all stock minus an open element air filter. Do you think a new oxygen sensor, air filter, Seafoam (type) treatment, and maybe some new plugs, an oil change and an EEC filter will take care of it?

The guy was pushing the car much harder than I do while I'm driving it, the temp gauge hit about 210 at the end (almost always stays at 200 +-5, in all weather and driving conditions).

it may, after a year or two the O2 sensor starts to get lazy.
check for codes.
a check of the fuel pressure wouldn't hurt.
check all your vacuum lines. if you have a way to scan it, make sure the data looks good.
if you do Seafoam it, do that first before you change or replace anything else.

I was not able to get my hands on an AC Delco brand O2 sensor, I couldnt find one anywhere but at the dealership and the guy at the dealership said he'd call back and didnt etc etc....but i was thinking about all of these emissions hoses. I am really not sure what goes where. i have the diagram, but it just isnt detailed enough for me to tell if i have it right. I figure if i have the fuel pressure regulator hose mixed up with the EGR hose i could really mess up emissions. is there anyone who can take detailed pictures or at least give a detailed explanation of where the hoses go? im at my wits end, so i figure it must be something simple like this...

http://www.dmvnv.com/emission.htm#Fail

According to this site, you can get a waiver. I assumed you are in Nevada still. You might be screwed because you spent all this money before your official test.

I went through the same crap. Believe me, I spent a but load of money on the car and it still failed. I had the luxury of having the previous owner fix it because he sold it to me without testing. Still, the problem was figured out.

Injectors, trust me, I'd get a cheap set of the SVO injectors and replace them. Don't even dink around with the stock injectors. I am pretty dang sure that you have 1 or even more injectors that are leaking, or, are bad.

Mine had 3 and 7 as bad injectors and they were replaced. Than it passed.

Now, there was a catch. The tank vent system was not venting properly. They replaced the canister, the release valve and it still wasn't passing emissions.

Now, there is a vent on the bottom of the tank, right close to the rear end that is designed to let fresh air in so the tank wont colapse from the pressure. If the tank is building too much pressure and the canister cant compensate for it, it vents right through the vent. Now, think about it. If that tank is building too much pressure and its venting out, the sniffers pick that **** up immideatelly. No wonder it runs rich, it just sucked in pure gas fumes.

Still, 90% of my problem were the injectors, but seeing if your pressure relief system works would be worth it.

Push comes to shove, just stick a hose to the metal hose thats coming from the tank, and try to route the smell somewhere where it wont get picked up by a sniffer. This is a cheap alternative, and much like other cheap alternatives they are really not to be attempted. But from a person who failed emissions 8 times all together, I had to take drastic measures. I am still baffled as to why my tank wont vent, and I checked all the lines.

Now, I have a fuel filter hooked up to the vent line and my tank vents through that. It smells like fuel, but only on the hottest of days, but my pump does not whine anymore.

This is worth checking out.

So far I've changed the spark plugs, changed to O2 sensor, got a new air filter, put some STP fuel injector cleaner in the tank, checked the vacuum lines, changed the oil (engine and rear end, just for the heck of it), and I still havn't passed. Here it was the first test:

Emissions / HC Hydrocarbons / CO Carbon Monoxide / NOx Oxides Of N...
--------------------------------------------------------------------------
Stand. Units/____0.8000___ /_____15.0000______/_____2.0000_______
______________Grams/Mile________Grams/Mile___________Grams/Mile____
--------------------------------------------------------------------------
Reading: /______2.0813____/____34.2569_____/_____0.6791______

And here's the results for the second test:

Reading: /______1.4347____/____45.0818_____/_____0.7763______

Could this be because I'm still burning the fuel injector cleaner that's in my tank? Perhaps the engine's burning oil? Spark timing? Something else to think about: my car was overheating after the test, not smoking/steaming or anything but running 245 degrees or so on the gauge, it cooled off quickly and I'm still not having overheating troubles, nor have I ever. I hope I don't need a new cat...

Maybe new TBI injectors? I hope not.

I guess you did not read my post.

Your gas tank is emmiting the emissions that are screwing up your readings. If you were truly running that rich than your computer will throw a code. The car is running good, the tank is venting close to where the stupid emission tubes are hooked up to the exhaust. I am most certain thats what your problem is.

I coulda sworn, that the gas tank gases were vented up to the intake, for reuse, no where near the exhaust tip, hence the EGR valve.

If everything is working the way its supose to than yes it vents right back into your Throttle Body. However, the tank has a pressure relief valve that sits close to the fuel filter, tucked up a bit above the rear end. If too much pressure builds in the tank this valve will vent. Make no mistake, if your fuel is getting hot, or the lines going to the canister are plugged, the only place your car will vent through is the dang valve. I am not 100% sure of the valves purpose. It makes sense to think that it lets fresh air in due to vacums ability to colapse the tank without fresh air coming in. Still, it vents out if there is too much pressure. So, I would strongly suggest you check your system. Just run some compressed air through the lines and see if anything comes through. Than make sure that valve is functioning properly. Mine gives me hard time when i try to blow through it going towards the tank. Like fresh air would go in. Than when I blow it from the tank side, it gives me certain amount of pressure than it releases. The best way to notice this is driving it on a hot day and park it. Crouch right next to the driver side rear tire and wait a bit. If the system is overloaded on pressure, it will make a "Phshhhhhhh" sound from right over the axle. This problem is rather commont, from the research that I did. It looks like, for some reason, the later models 89 or 90 and up had this problem. I am thinking because the tanks vent from 1psi of pressure to 2psi of holding pressure. Still, when that sucker releases the vapor in the rear, there aint no chance of you passing. Its gonna look like your car is just incredibly rich, although your computer will tell you if you are running rich. There is a code for that.

I could not pass emissions for the life of me. Than I returned the car to the previous owner because he can't sell me a car that wont pass. He was kind enough to spend some serious money to get it going again. What was the problem you ask?? Well, they replaced two injectors because they were bad (and I knew that). Than they replaced the purge vavle on the charcoal canister itself. Than they replaced the spark pluggs, and the car still did not pass. They tried two more times and it finally passed (really clean). I got the car back and on warm days the fuel pump will start whining (after I drove it longer than 20 minutes). The rear relief valve would hiss after shut down telling me that something is wrong. Than after much pointless tracking all over the place I figured out what was going on. First of all, they blocked the fuel evap line that was going from the tank to the canister. This did not allow any extra fumes to enter the engine and exhaust. Than the car was taken in before it built up pressure and it passed with flying colors. If they were to wait and take it in after 20 or so minutes, they would fail because of the stupid vent venting the gas out.

I spent waaaay too much money on tracking this problem. I replaced everything you are talking about and it still had those problems. I would advise you look at this, and at least try to block the rubber line to the canister and take it to be tested quickly. Release pressure from the tank while you wait in line to get tested and hopefully you will pass.

Good luck.

P.S. EGR has nothing to do with fuel evap, its for exhaust gas recirculation.

Didn't get to try your fix xlwhellraiser, but I managed to pass! After all that junk I replaced, it turned out that doing two treatments with Seafoam through the TBI got my car running squeaky clean. I split the rest of the stuff between the gas and oil.

After I used it though, I took my TA to the test facility and on the second run (the first run the tester ran the car too fast and had to restart, reckless hooligan) the car got a "Fast Pass" sign about 30 seconds in! The car was at 1/2 and 1/3 the standards for the areas I failed earlier! Apparently that Seafoam is some really good stuff, I plan on getting that for my car for now on for engine treatments.