Failed smog check - help!

My 1995 Dodge Caravan 3.0L V6 failed the smog check or emissions test as it is called in Ontario here. Here are the results;
40km/h
Limit Reading Result HC ppm 62 60 PASS CO% 0.35 0.16 PASS NO ppm 0870 99 PASS
CURB IDLE Limit Reading Result HC ppm 200 861 FAIL CO% 1 0.23 PASS
The problem seems to be high hydrocarbons when idling. How do I reduce the high reading? So far I have done the following but have not retested it due to fear of failure; * Installed new spark plugs * Installed new spark plug wires * Got an oil change and new oil filter * Changed air filter * Use "Guaranteed to Pass" additive
What is the real problem with high hydrocarbons? How do I pass? Any ideas and suggestions are welcome. My mechanic thinks there is a "vacuum leak" and it may cost $550 to repair it but I am not sure.
I think it may be just due to the fact we went to a garage two minutes from our house to test it without warming the van up sufficiently. Do I have to run it on the highway before going in for the test? Thanks.
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Kelsey Jones ( snipped-for-privacy@yahoo.ca) writes:

Its also borderline under load. Another day it could fail.

you only need to spend $200 trying to fix the problem to get a condition one year so you can register and drive the car. look at www.cleanair.ca (or .com ?) for Ontario rules. I would not just repalce the converter as some places would get you to do without first diagnosing the problem. It could be a waste of money.

this might help ...
As I understand it from reading (I'm not a mechanic) high CO means a rich fuel mixture, either too much gas or too little air.
Too little air can come from a dirty air filtre, stuck choke, plugged or sticking PCV valve or EGR valve or hoses, plugged corburettor or injector air passage. You can check all of these.
Too much fuel would be a problem in the carubretor or fuel injection.
Either can be due to problems with the emissions control system - vacuum hoses, sensors, actuators, or from poor ignition. You can check the hoses and do some checks on the devices with a voltmeter if you want to get into it.
If there is not enough air then the Nitroen reading would also be high.
It could also be a faulty catalytic converter.
-- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or it's returned
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http://www.driveclean.com
The emision limits have been lowered by 11.5% since inception. That will happen again next year. The RCL will rise to $450 on June 30th, 2004, in Phase Three. It already is that much in the rest of the testing area. http://www.ene.gov.on.ca/envision/news/2002/121701.htm
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cant we just give them 200.00 for a sticker
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William R. Watt ( snipped-for-privacy@FreeNet.Carleton.CA) writes:

only in year 1 and 2 of the program in your area, then it goes up to $450 as noted in another reply. Here in Eastern Ontario we're in year 2.
I got the website wrong, and was corrected - www.driveclean.com. the toll free number is 1-888-758-2999.

sorry about that. when I went off line to check my notes I misremembered the test result. I looked through a few books at the library some time ago and took notes. here is what I have on high HC ....
caused by incompelete combustion - unburnt fuel blows out exhaust
a) rich fuel mixture (too much gas and not enough air) is only a problem if both the HC and CO are high. not so in your case.
b) lean fuel (too much air, too little gas) causing uneven, incomplete combustion - look for air leaks in hoses, gaskets, EGR and PCV valves
c) poor ignition not completely burning fuel - look at spark plugs, wires, etc.
d) combustion chamber too cold for complete combustion - look for sicking EGR or exhaust valves, or bad valve timing (I cured a problem here with one of those engine chemical cleaners, the one that goes in the oil just before changing oil. the one that goes in the gas tank had no effect) - if the valves are noisy they might need adjusting which you can do yourself if you want - you can also do a compression test to see if valves are not closing completely due to carbon build up
e) hot spots in combustion chamber preventing complete combustion (engine misses) - engine chemical cleaner can clean out carbon but not nicks in metal.
f) not enough air in exhaust system to for catalytic converter to convert HC to H2O and CO2 - look at pulse air system or whatever the car uses to feed oxygen into the converter
g) faulty converter - somebody already gave a better explaination of this than I have in my notes - unfortunately I know of no test for catalytic converters which I why I suspect 'way too many good ones are thrown out. muffler shops in Ontario are renowned for telling customers their coverters need replacing when they don't. they were doing it long before Ontario had emission testing. :(
one obvious indicator of high HC is a rotten egg suphur smell in the exhaust as excess HC combines with S (sulphur)
... hope that helps
-- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or it's returned
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snipped-for-privacy@yahoo.ca (Kelsey Jones) wrote in message

I had a Honda Civic fail once for the same reason, and all I needed was a new muffler. There could be other reasons for a vacuum leak, but get it checked. If your mechanic is the one doing the test, have someone else check your van. You do not need to drive your van on the highway prior to the test.
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If it really was stone cold then the catalytic converter wouldn't probably have been hot enough to work. If a warm engine doesn't pass then I would agree, look for a vacuum leak, but $550?!?! It shouldn't take that long to find a vacuum leak! I'd also suggest cleaning the throttle body if the van has high mileage.
Ted
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High HC is LEAN. Too much air, not enough gas. Can be caused by gasket leak or stuck EGR or bad Oxygen sensor. It's too high to be fixed by a catalytic converter replacement. Good luck! - Bill

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Nope. High NO could be caused by lean running but not high HC. It's a chemical reaction, too much of one component means that component get's left over in some form.
I could see how a stuck open EGR might cause it, however.

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Bob Hetzel ( snipped-for-privacy@blackout.DMS.cwru.edu) writes:

My 1989 carburetted Festiva passed the emission test today - barely.
The CO and HC were excellent but the NO was borderline. I suspect leaky exhaust valves. I plan to do a compression test to check it out when the weather warms up. If it shows leaky valves I'll take the valve cover off and gap them to spec. and see if that fixes the compression. I was really surprized at how well it did otherwise. It was a cold day so I took the car for a drive to get it really warmed up before the test. I also checked the tire pressure before taking it in.
Here are the results ....
Dynometer Idle
Limit Test Limit Test
HC ppm 109 10 200 0
CO % 0.61 0.00 1.00 0.00
NO ppm 1292 1045 n/a n/a
Its interesting that the catalytic converter the crooks at Midas have been telling me is shot and needed repalcement was not a problem. So many perfectly good converters have gone to land fill because of crooked muffler shops.
Its also interesting that this 15 year old car only has to pass two more emissions tests before its 20th birthday and is thereafter exempt from emissions testing.
At the test center there is a brochure called "What if my vehicle doesn't meet the emissions standards?" which lists possible problems for each pollutant. I checked www.drivelcean.com but unfortunately the list isn't on the website. I'll try to type it into a computer file and post it here sometime in the next few days.
Under NO it lists - EGR system - lean mixture - faulty converter (3-way only) - too much spark advance - thermostatic air cleaner system - engien deposits or mechanical defect - cooling system
my notes say NO only forms pollutants at tempertures above 2500 deg F so too much heat in the cylinder is what causes it. If teh EGR is not recirculating gas to cool the air/fuel mix NO pollutants can form.
-- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or it's returned
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William R. Watt wrote: >

The scrap steel from exhaust systems is recycled and the platinum and other precious metals in the cats is removed and recycled.
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A miss from a vac leak could raise the HC. If you're concerned about the high HC reading then the first thing to do is check the O2 output while the car idles--make sure it's switching as you tap the gas.
Run the car on the highway. Or rev it at 2K-rpm for a minute or two to heat the catalytic before taking it into the smog bay. This depends on wether your state run the idle test at the end or beginning of the cruise test.
-- Milo
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