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RECENT EMAILS: Failed emissions test. Smog check failures. Broken speedometer. Guaranteed smog repairs by emissions repair station. Oversized truck tires. NOx failure. Chevy, Toyota, Mercedes, MBZ, Pontiac, Geo, Mazda, Mercury, Ford, Infinity vehicles.

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Question: Smog test showed that the idle for my 1993 Mazda MX6 is set to high. [Timing is at 10 degrees BTDC at 1150 rpm and 10 degrees BTDC +/- 3 degrees st 850 rpm +/- 100 rpm.] The car passed the emissions test. My questions follow: Will retarding the timing be sufficient to pass the smog test? or will the emissions increase as a consequence of reduced rpms? Will a tune up take care of the timing or is it more complicated requiring a visit to Gold Shield repair center?
 
Answer: Question is... is the timing set to the manufacturers required setting? If it is, the high RPMs may be due to perhaps an idle air adjustment, or other adjustment your particular vehicle may require effecting engine idle. If the timing is off, then by all means, correct it. Remember advancing timing will causes higher RPMs and higher emissions. Retarding timing (slightly) will lower idle and emissions as well. But be careful with retarding timing. Too much, and the emissions will skyrocket. Also keep in mind, you have to stay within the 3 -/+ mark. And yes... a tune up should include a timing adjustment.
 
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Question: I have a lifted 2000 Chevy Silverado 2WD on 40 in. tires. This is the first time I have to get the truck smogged since the lift. I blew the rear end out not too long ago and had to get the gears redone. Now when I drive the speedometer is a little off when I drive; not too much on the streets its more when I am on the freeway. It is about 5-7mph off on the freeway and when I go faster the difference just increases. This does not happen til I start to go above 55mph. Will this hurt me when I go get the truck smogged.
 
Answer: The 40 tires are going to make your vehicle's engine work harder on the dynamometer during the smog test. This in turn is going to produce more emissions. On a sound operating engine, the tires might not effect emissions to a failure, but assuming your vehicle's engine has a few miles on it and maybe is running at a slightly less then maximum efficient combustion, these tire will pose a smog threat. Our recommendation is that you have the vehicle inspected with the original manufacturer recommend tire size/s.
 
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Question: I need to get a smog check (2001 Ford Ranger), but I have a broken speedometer. Will the smog station still run the test on my vehicle?
 
Answer: Yes, you can still pass the smog test. The speedometer is not part of the smog test.
 
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Question (a): I have a 1996 Chevy S10 4.3L auto 2wd. No check engine light on, runs ok. 103,000 miles. At last smog test, CO and NOX passed well, but HC was at upper limit. What could be causing this, and what do I do to fix it?
 
Question (b): I had a 1998 Toyota 4runner fail smog today . The ppm was too high at 15 mph. They wanted 100 dollars to diagnosis plus repair costs. Do you have any idea what I should try to fix on my won first. I changed the pvc valve, oil change and new air filter. Is there something else I should fix ? Also I didn't really drive the car very long before test , could that have been the failure?
 
Question (c): My car is 1992 Pontiac Grand AM ES, Quad-4 Engine inline 4 DOHC. My car don't have E.G.R. I was shocked. I know EGR will help low NOx ppm.. but how can I pass emission test without EGR. My car is only just almot 72,000 mile. I know other possible is catalytic converter (CC) but I doubt because cc is still newer due to low miles 72,000.
 
Answer: Vehicles fail their smog inspection for different reasons based on the variety of emissions control systems used on production vehicles. We recommend using our SmogSmart VIR Report system. We'll be able to give you a much better idea of what your vehicle's emission problem might be. The SmogSmart VIR Report system will ask you to fill in all the information our report system & technicians need to effectively evaluate your vehicle's emissions failure. You may also use the "Additional Information" section of the blank form to include detailed comments. To obtain your vehicle's SmogSmart Report, please visit the On-Line Evaluations Page at www.smogtips.com/smog_evaluations.cfm
 
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Question (a): I have 1979, 280SE Mercedes MBZ. My car failed in smog test because NO (PPM) measurement was 1933 at 15mph, which exceeded the maximum value of 1277. What I need to do to my car to bring down the NO measurement to an acceptable value?
 
Question (b): My car (2001 Infinity) failed smog at a test only station.  It failed the Nitrogen component.  It has 1100 PPM.  I think allowable was in the 700-800 range PPM. The car passed on the other smog categories.  What part of the smog system should I concentrate on if it failed the Nitrogen component.
 
Question (b): I have a 94 Geo Prism that has no EGR system and failed emmisions with excessive NOx & no computer codes listed nor check engine light. What are likely causes.
 
Answer: There are several reasons vehicles encounter NOx failures. The most common is the malfunctioning EGR system (if a vehicle is equipped with this component). EGR stands for exhaust gas recirculation. And that is exactly what this component does. The EGR system recirculates burned up exhaust gases back into the combustion chambers. Since these recycled exhaust gases have already been in the combustion chambers once, they have burned up most of their fuels, means there is now much less real fuel in the chambers to ignite. This keeps the chamber temperatures down and thus reduces NOx emissions. The EGR valve should be inspected to insure its proper operation.
 
A working valve should be able to open its passage using manifold vacuum. Manifold vacuum is created during the engine's intake cycle. The high demand for air during this cycle creates a vacuum within the engine's intake manifold. This vacuum is then used to control several important functions within the vehicle, including controlling the EGR valve. Some vehicles even rely on this vacuum to control their heating and air-conditioning components. The EGR system is prone to collecting carbon build-up. Some vehicle manufacturers recommend cleaning this component an a regular basis. Another NOx causing problem: Lean fuel mixtures due to vacuum leaks may also cause high NOx. A “lean fuel mixture” is when the engine receives less fuel then is necessary to obtain clean combustion. Vacuum leaks are open passages, normally due to defective gaskets or vacuum lines, between two engine components. These leaks will allow the suction of additional and un-metered air (oxygen) into the combustion mixture or exhaust (depending on where the vacuum leak is located) disturbing pre/post fuel combustion and increasing NOx emissions. Vacuum leaks can be difficult to locate if they are present at locations not easily seen. Bad engine cooling causes high NOx: Engine cooling problems may cause high NOx also.
 
If your engine's cooling system is not working efficiently, chances are there is an excessive amount of NOx being created. Remember NOx (Nitrous Oxides) is created only when an engine's combustion chamber temperatures reach over 2500F. A bad cooling system will create NOx. For this reason you want to make sure your vehicle's temperature gauge is always normal and that your cooling system is working properly. Got high miles? High compression can cause high NOx too:  High amount of carbon build-up within your engine's combustion chambers will cause increased engine temperature and high NOx. Carbon build-up normally develops in an engine's combustion chambers over some period of time. High increase in carbon build-up causes increased cylinder compression, which causes high temperatures, which result in high NOx emissions.
 
Keep in mind this problem is usually seen in vehicles with over 200,000 miles. The solution to this problem is called an Engine DeCarbonizing. It usually costs around two labor hours at a smog repair station. It will remove a good amount of carbon of your engine's piston heads and valves. This will increase combustion space, lower compression and lower NOx.
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Question (a): If I have a car (97 Mercury) that has quite a few problems so that it will not pass a smog check, what can I do?
 
Question (b): I have a Mazda Protege 1994 and it does not pass the smog check at all.  Every mechanic won't tell me what is really wrong so that it can pass. What should I do?

Answer: The next step if to have a certified smog repair station take a look at your car. You should give them the failed report, but I'm sure they will want to run their own tests also. Either way they will charge a diagnostic fee to figure out what the problem is. This is normal. I would just ask the station owner if he/she will guarantee the repairs. In other words, if they say the car needs a CAT, and you let them replace it, will they guarantee your car will pass? So just ask these questions and if the answers make sense then go for it. Some times it is possible not to be able to promise a passing car. Some times the problems a vehicle has are just to many and by replacing one component there is no guarantee to pass.
 
 
 
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