Emission Test - MAJOR HEADACHE

Some things to note:

"Guaranteed to Pass" and other additives that are supposed to cure a problem rarely, if ever, work. If the stuff is guaranteed, get your money back.

A catalytic converter does not have to be "burned in" to work.

From your initial emissions test results, the high HC was likely due to ignition misfire. If the spark plugs and ignition wires have more than

60,000 miles or are an aftermarket brand, I recommend that you replace them with OEM parts. As far as your emissions test results after replacing the catalytic converter, I would say the replacement catalytic converter is defective and not working. An exhaust leak would not cause the readings you are not experiencing. The catalytic converter that you took off the vehicle was probably good, and it was replaced with one that is not good.

The shops where you have been taking your car for repair apparently know little about emission control systems. I recommend that you take your car to a Toyota dealer or a shop with ASE certified technicians for diagnosis and repair in the future. Unfortunately, it looks like a relatively simple fix has turned into an expensive one.

It seems more accurate to say, an expensive non-fix.

jeff

I stand corrected! ;-)

Your car failed the "25% load" test. You may have not needed a new converter to begin with but now that you have it, that component can most likely be eliminated as faulty. The shop you are dealing with IMHO does not fully understand emissions systems and associated problems. The suspect front pipe leak must be checked and repaired if necessary. It will allow a faulty reading from the first (ahead of the cat) lambda sensor. Here is my two cents on a possible remedy. First, clean and make certain that the EGR valve is working properly by cleaning and verifying operation at closed loop. Secondly, swap O2 (lambda) sensors. The sensor after the cat is basically a performance monitor of the conversion process. The sensor ahead of the cat will monitor fuel / air ratio and speak to the computer that varies the fuel supply using the injectors, trying to keep the ratio perfect (14.7:1). Thirdly, just before the test make sure that the vehicle is at operating temperature. The conversion process using precious metals is most efficient at higher temperatures. I hope this works for you. You have spent alot of money on this when IMHO, a shop that supposedly understands these issues has unfortunately not been helpful. You may want to take Ray O's good advice and seek another shop or the dealership. Good luck.

< snipped >

Not clear on what you are saying... are you saying the new converter is probably working fine and not the problem? If that is what you are saying, then goes against what Ray O believes.

This car has 2 sensors ahead of the cat. Again Ray O does not believe that a leak would affect the reading drastically like I have experienced after installing a new cat.

I paid for an Emission Analysis in the hope of finding what is faulty on the emission system... I would hope the EGR valve was one of the component tested.

Is it the same O2 sensor used before and have the cat? If so, then I could simply switch the back one with one of the front ones?

The car was driven for almost 4 hours when I took it directly to the test center... It was as hot as can be.

I thank you all for you good advice. Only problem with taking it to the dealership now is that the reason I bought a used car to begin with and bought the parts myself was to save money. I'm at a point where I have sunk $1000 in trying to get this car on the road and despite all the advice from on here and from various mechanics, I seem no closer to figuring out what is wrong and who screwed me. :-(

The new converter is probably working as specified, faulty converters are very rare indeed. Faulty installations are far more common. Make certain they installed it correctly.

Any leak that alters the content of the gases coming directly from the engine will affect the lambda sensor reading by the computer, thus misinterpreting and signaling the incorrect fuel to air ratio. The pipe must be sealed. A lean condition can lead to high HC outputs and a rich condition can lead to a damaged cat.

They usually are, but I am not absolutely positive on that vehicle. You may also want to remove them to check for any buildup on the outside of the sensor, clean it off with a clean rag and carburetor cleaner. Remove them when the engine is cold. Reapply anti seize to the threads before installation.

Good, the hotter the better.

On Apr 26, 7:06 am, " snipped-for-privacy@gmail.com" wrote: I seem

I think it's fairly obvious the new cat is not working as well as the old one. I saw the same thing when I changed the cat on my accord. The scores actually got worse. This leads me to believe many of the aftermarket cats are not nearly as efficient as the OEM versions. Any exhaust leak large enough to cause a problem should be hearable, if you know how it sounded before. If no audible difference, I doubt that is the problem. Judging from your first test, all I can see was you might have been running a tad rich, or had a misfire. The worse score was at speed, so that tends to lean more towards a misfire I would think. But you have to look at the whole system. IE: if the temp sensor was out, that could cause a rich mix if it stayed in open loop. Sorry to say, but the cat was a total waste of money. "I went through the same thing". You need to find out why it's slightly rich, or misfiring, and that will probably do it.. I'd seriously consider asking for a refund or replacement on the cat. It's obviously not working worth a hoot.. They have a min

25k mile warranty. The bad part is, even if you fix the *real* problem, I bet you now will have trouble passing due to the poor functioning cat.. I know one thing, if I ever change a OEM cat, I'm going to request that I can keep the original. Actually, if I ever change an OEM cat again, it's probably going to be another OEM cat, even though the cost is very high. I'm totally convinced that many of the aftermarket cats suck. IE: the new maremont cat I bought did worse than the 18 year old OEM that was on the car. Ain't that some crap? I've found that cats usually don't go bad unless they have been abused with a rich mixture, misfires, etc for a good while. So I've been leaning towards always looking at the cat as one of the "last resorts".. I feel for ya.. You had a simple fix, that was buggered up by incompetant mechanics. I think they should pay to correct the problem, being they misdiagnosed it. I know for a fact that many mechanics are lost in space when it comes to emissions repair.. They tend to poke and guess... And you end up paying the price which keeps going up, up, up, due to their incompetance. Also some shops will quote a price to fix, and inspect, and end up not fixing the real problem, and then they "fake" the test by using another car.. Then the next year, you get to start the same sick cycle all over again. I've gone through this myself... I eventually bought the books, etc to learn to do it myself. I had a chevy monte carlo that went through this. They poke and guess, new carb, new this, new that, and it still failed, but they faked it through..So I had to deal with it again the next year.. I had to fix it myself... The *real* problem? The two "air" pump hoses were routed backwards.... I corrected that, and it blew a score so low, I almost wet myself. MK

I understand how you feel, but it might cost you a bit to keep your original cat. Prices run between fifty and seventy USD at scrap metal "recycle" yards. They remove and reclaim the precious metals from them.

Is it possible that the shop that did the Emission Analysis unhooked or messed up something as they were the only one to have worked on the car prior to replacing the cat and seeing the readings shoot way up. I also noticed that they never replaced the plastic engine cover and it's now missing.

In my experience, OEM catalytic converters have a very low failure rate, while bad aftermarket converters are not that uncommon. There are sosme very expensive metals inside the cat, which is why they are so expensive. Automakers have to warrant them for at least 80,000 miles now so OEM cats are pretty reliable, I suspect that one of the reasons aftermarket cats cost so much less is that they use a much thinner coating of those expensive metals.

An exhaust leak can affect the performance of emissions controls, however, they are usually audible, and the testing station is supposed to check for exhaust leaks before performing the emissions test.

A simple check for an exhaust leak is to take a bunched up rag and hold it against the tailpipe while the engine is idling. It should be very difficult to stop the exhaust coming out of the tailpipe, and there should be no increase in exhaust noise.

I doubt if the shop checked the operation of the EGR valve. More likely, they plugged in a scan tool or used an exhaust probe to take readings. A problem with the EGR valve would have caused high NOx readings and/or driveability problems.

Whether the O2 sensor is the same before and after the cat varies by vehicle. You can check part numbers at an auto parts store or dealer.

I think your best chances to get thee car fixed at this point are either take it to a Toyota dealer or invest in a volt/ohm meter, available for under $40 at Radio Shack and a Haynes, Chilton's, or factory repair manual . You can check just about every electrical component in a vehicle with a meter, including the O2 sensors.

To check the performance of the replacement cat, a shop with an exhaust analyzer will have to probe the exhaust ahead of and aft of the cat to see if it is working.

I guess anything is possible, it's difficult to diagnose on a news group, but perhaps you should consider another shop. If they are not replacing parts or re assembling parts incorrectly, that could add to all of your problems. The money spent on someone competent and experienced could save you substantial sums in the long run. Maybe you get some feed back from other Toyota owners locally where they do business for repairs. IMHO.