Well, I failed the emissions test yet again. NOx
me: 1.1
Limit: 2.0
PASS

HC
me: 2.38
Limit: .80
FAIL

CO
me: 55.23
Limit : 15.0
FAIL

I did it without any preparation this time...for a before and after effect. I am planning to change my oil, get new air filters, and drop a couple bottles of Isoheat now. I am pretty worried about how high the CO is though.
My HC and CO are pretty jumpy to on the charts.
Do you think this stuff will work for me....or am I going to need more extreme measures.

 

I am by no means an exhaust expert.
CO could be running rich. 02 sensor.

I would run some injector cleaner, "cat-clean" some brand of catalatic converter cleaner? I dunno I only have seen it twice.

The iso heat will not do much. It only gets out water from gas.

oil change MIGHT do something. doubtful...
try cleaning the EGR and ports...
I used to know all kinds of tricks, but then I moved to a No sniffer zone and over the years I forgot most of them...

Get highest octane gas you can and run around and get the car nice and hot before the test. If there is a wait, KEEP THE CAR RUNNING. You want that converter as hot as it needs to be for the test. I had a few tests that the guy told me to go around the block a few times to get the exhaust system up to temp and then I passed.

If you are running crap gas now, BURN IT UP and get GOOD gas.

 

Clean your cat.
When your car is hot go to a big hill or the interstate and hold it wot for as long as you can. When you do that they can glow red, do you think any HC's can survive through that? It will make all kinds of weard smells when you do it.
Then go get it sniffed.
Alcohol will help you burn cleaner too.

 

one more.
With your low NOx #'s you know for sure your not running rich.

 

Do a tune up
Change plug wires
CHANGE OIL (is a BIG HELP)
Do the CC trick mentioned
Definetly fresh air filters
Yes, higher grade of gas, too.
ALSO CHECK ALL VACUUM HOSES TO MAKE SURE you have great seal and yep, do clean out the bottom of EGR.
Unless the 90-92 EGR, new EGR goes for about $30-ish.

 

I found the main culprit of my problem tonight. It seems that the cat was gutted at some point.
Also, my cousin swears by the IsoHeat. He puts 2 bottles in a quarter tank of gas, and has never even come close to failing.
Anybody have any idea why this could be?

 

My secret receipe is to add two bottle of Liquid Gumout for Fuel Injector cleaning and again, Premimum Gas.
After the tune up, go to freeway, waste the whole tank of gas and then go to testing.
Works on my ride.
In SoCal I go thru the most demanding emission testing. Last test I registed zero on some emission test parts.
Read the label of the can in question and see ingredients. Maybe there is your answer.
Make sure you have the true specific spark plugs called for in your engine.
When I swapped in the 1995 3.4, I found 2.8 spec'd spark plugs in this engine.
Wrong heat range plug will also throw off emissions, causing testing failure.
See if ya can score a CC from a used 1993-1995 range F Body.
That AC Delco CC is very high flow & effective.

 

My 2 cents...

Run a full tank of Amoco Ulitmate
then fill the tank with...

2 Gal of Amoco Ultimate
+
1/2 Gal of 70% rubbing alcohol.

Then test after getting good and hot.

After the test, burn the rest of the mix out and fill up again.

Its worked for me.

 

Well, I changed the cat., and HC went down a little...not enough to count reallyNOx is almost nonexistent and CO went UP to 58 grams per mile.
What would cause the CO to be so high?

 

I'd agree with running rich. High HC + High CO usually point to a rich mixture.

You can usually nuke high CO with a clean air filter. Not enough Oxygen into the engine (due to dirty filter) means that your Carbon can't make CO2, it only makes CO.

I'd check for a misfire somewhere. One misfiring cylinder can put out enough emissions to cover 20 "passed" cars. Plus, a misfire seems about right, b/c HC's are unburnt gas.

How's your timing? That can throw off your HC's - and I think it can also throw off NOx.

You can still run lean and get high HC's because if the gas mix is too lean, combustion won't be "complete", it'd be like a "spotty" fire instead of an even explosion.

Do they make you run on a dyno, or are you just idling? If you're idling, then the EGR won't kick in at all, so you don't have to worry about that part.

Here's my smog checklist- and they make us go on the dyno in NJ.
1. clean/re-gap plugs
2. clean distributor cap & rotor
3. check spark plug wires with ohm meter, replace any out-of-spec
4. check timing
5. new air filter
6. oil change
7. clean out throttle body and IAC pintle/passageway
8. check TPS
9. bottle of "Guaranteed to Pass" in a full tank of gas, drive car until tank is almost empty, fill tank up again, and quickly get tested

Now keep in mind that I do a major tuneup every year, so I don't have to go out and replace anything, I just check 'em over.

 

I run on a dyno
my timing is at 12* BTDC
The air filters are K & N with about 10k on them would new ones really drop CO that much? Could I just take the K&N's out just before the test
Where do I find this "gauranteed to pass" stuff.
My entire ignition system isn't more than a year old
How do I find a misfire this small? I can feel/hear/see a bigger misfire, but I don't notice anything in particular now.

 

When I had my K&N going, that's what I'd do- I used to keep a brand new paper filter from Kmart ($6), in the basement, in it's box. When emissions time came around, I'd pop the $6 filter in, go for the test, and after I passed, I'd put the K&N back in.

You basically just check/pull/time/clean everything as I described to find a small misfire. Could be that one of your plugs opened up to 0.055 and that's the problem, or one plug wire is 24,000 ohms/foot instead of 15,000 ohms/foot (stock wire).

Aftermarket spark plug wires will vary, of course... like on my '86, my MSD 8.5mm wires are 50 ohms/foot. So if 5 wires come out between 40 and 60 ohms/foot, but one wire is 3,000 ohms/foot, I replace that one "oddball" wire.

 

k...I tested my wires.
I got readings all over the spectrum...I had to change the setting the ohmmeter was on to read them all.
with the meter on the "20kohm" setting i got 8.7,.88,1.07,and 6.4 I had to change to the "200kohm" setting to get the next one, it read 140.xxx. and the last one wouldn't even give a reading.

Well...the new wires were much better, and after putting them on, I don't get a burning in the back of my throat and I don't feel dizzy after sniffing the tail pipe.
So I've made some progress.

 

So you had one plug wire OL, that would be your missfire.
Did you check your plugs? See what they look like.
I advanced the cam timing on my toyota over here and got better gass milage and it ran better.
If you keep your car runing top notch, all turned up and every thing I would bet you could pass with out a cat.
The main thing the cat does is keep your exhaust clean even when your engine is runing like crap.
I went to school with a guy from L.A. that could pass smog with gutted cats, he had a late 90's 4.6L stag and had some trick flow preformance package (heads, cam, intake, tb headers) with a nice MSD ignition and a few other things. It can be done.

 

Another easy way to check plug wires is simply open hood at night, in a no light situation.
IF ya got bad plug wires, you'll see a lightening storm all over the plug wires.
Same with a plug wire with a short/cut/nick, you'll see that lightening storm all over the plug wires instantly.

 

Well, since I kinda ran out of time to get this done, I registered in another county.

Thanks for all the help though

 

What???

 

WRONG!!!

NOx is caused by excessive heat in the combustion chamber, if you are running rich, you have all that extra fuel sucking up the heat. No heat, no NOx. Running rich, HIGH CO. I do this for a living, I should know. They drill this into our heads out here in California.


Looks like you are running rich. What is your Oxygen %??? if it's close to 0%, then for sure you have a fuel control problem. I suggest you start thinking about leaking injectors, bad regulator, or anything else that might cause a rich problem. Check your EVAP canister, if you have a clogged purge signal hose, then you havn't done a full purge in a while and could be getting all the extra fuel from an overfilled canister. If you could maybe scan the printout and post it or something, I think it might be more useful.

 

Where is my EVAP canister, and how can I purge it?
I've replaced, cleaned, fixed, timed, just about everything and still I run rich so maybe that is the case

I don't have time to scan the printouts now, but there are a lot of peaks on both the HC and CO and they max out the graph.

 

I serioulsy doubt a canister will be causing your troubles. In all the years from 1985, my cars canister has never been touched.
Frustrated?
Sure
What does a mechanic say?
What about the testing place?
Hell out here in CA, we got the same car parts as yourself.
What is "so wrong" with your car to cause this "problem"?
I mean I am running a used 1995 engine under 1985 MPFI stuff & I get great results.
One benefit from all this tune up stuff is your car should be running much smoother than before.
IS IT?
How does your exhaust smell?
When was last time convertor was changed?
Oxygen sensor, too?
How good are the plug wires?
Change oil yet?
These are common sense solutions, but hope I haven't repeated any of your efforts.

 

EVAP canister should be on the driver side right behing the headlight...looks like a large soup can with vacuum lines to it. Just make sure that all the lines are hooked up and intact, then sqeeze them to make sure that they aren't plugged. Make sure that you sqeeze every inch of them because one small obstruction can screw the whole thing up. This isn't very likely the case, but possible. I have heard of a lot of people having problems with their EVAP systems on this board lately.

The more likely thing that you should be looking at is the fuel system...leaking injectors, bad regulator, that sort of thing. Also might want to look at the IAT for proper operation and, I can't remember if it was mentioned, but replace the O2. When they go bad the read all the way lean, so the computer thinks it's lean and adds tons of fuel, but since the O2 isn't responding quickly enough, it doesn't set a code. It just tries to stay in open loop, then get a tickle on the O2, slams into closed loop, and it's an endless cycle

 

Well KED unfortunately you just repeated my efforts...I've done everything on that list.
I replaced the O2 last year, but yeah....the readout would lead me to believe that is the problem since its so jumpy.

 

i did a full tuneup similar to tomp's and they thought my car was a iron duke and it still passed with flying colours.