 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Car Forum / Nissan / Nissan Cars / September 200594 Sentra Fail on SMOG with HIGH HC & NO
Hi All, I live in California and recently bought a used 94 Sentra w/ 1.6L stick shift. However, the car can't pass smog. The car fails with high HC and NO, both at 15mph test. HC(PPM) measures MAX:92, AVE:21, MEAS:178. NO(PPM) measures MAX: 716, AVE:150, MEAS:938. At 25mph test, the HC barely met passing standard with HC(PPM) MAX:57, AVE:13, MEAS:57. The NO at 25mph passed below AVE measured value easily. I've never had a car can't pass smog, so all these are pretty new to me. Can someone with some smog experience or expertise give me some advice on where to look or what to fix? Thanks for helping. Anson retard the timing at least 10 degrees and try again, worked for me! > Hi All, > [quoted text clipped - 10 lines] > > Anson So my Sentra's timing is off that's why it's producing excess HC & NO? There isn't anything wrong w/ EGR or Cat? > retard the timing at least 10 degrees and try again, worked for me! > [quoted text clipped - 12 lines] >> >> Anson > So my Sentra's timing is off that's why it's producing excess HC & NO? > There isn't anything wrong w/ EGR or Cat? The answer he gave is a way to cheat it to pass. The timing isn't "off", more likely you are running CHEAP gas and it's causing it to fail.  SignatureSteve http://www.atlantaracing.com okay, let me give you more detail on my car so maybe you can tell more about why "cheap" gas would causing it producing more HC & NO when timing isn't "off"... My car is 1994 Sentra with 1.6 liter (GA16DE) and 5spd manual transmission. Current mileage is at 188K. I am the second owner, the previous owner had the timing belt replaced with a timing chain (kind of hard to believe) in order to avoid costly future timing belt replacements. I hope this replacement doesn't have anything to do w/ not passing smog, because the car runs just fine. When the car didn't pass smog at Test Only Station this time, I took the car to a garage and was told that I need to pay the mechanic $200 something to get the throttle body all cleaned maybe even EGR check-up and repaired if any. However, the mechanic wouldn't give me a written estimate. Is he trying to jack me by not wanting to write an estimate down on paper for me? I also went to see a muffler guy who told me that he would just replace the Cat for $100 and after it should pass but he's not guarantee it. So now I am confused about what I should do without emptying my wallet over this little car. I would like to know the root cause of why this car is not passing smog or is there no easy fix? >> So my Sentra's timing is off that's why it's producing excess HC & NO? >> There isn't anything wrong w/ EGR or Cat? > > The answer he gave is a way to cheat it to pass. The timing isn't "off", > more likely you are running CHEAP gas and it's causing it to fail. > okay, let me give you more detail on my car so maybe you can tell more about > why "cheap" gas would causing it producing more HC & NO when timing isn't [quoted text clipped - 25 lines] >>The answer he gave is a way to cheat it to pass. The timing isn't "off", >>more likely you are running CHEAP gas and it's causing it to fail. You can clean the throttle body yourself. Make sure to use cleaners that are"safe for fuel injected engines" Do not use carbuerator cleaner. Here's some PICs from Motorvate's website of how he cleaned his Maxima throttle body. It's a very similar process on the GA16DE; http://www.motorvate.ca/mvp.php/517 Now, I would think that cleaning the throttle body may not clean up your emissions completely, perhaps the cat converter is dying. IF so, try testing when the car is really hot so the cat can work at its best. If you need to replace the cat, go aftermarket. It's way too expensive to go OEM. FYI, you cannot replace a timing belt with a chain. That would mean the engine was completely re-designed. The GA16DE had a timing chain from the day it was born. Timing chains usually never need replacing. The previous owner was playing with you. CD > okay, let me give you more detail on my car so maybe you can tell more > about why "cheap" gas would causing it producing more HC & NO when timing [quoted text clipped - 25 lines] >> The answer he gave is a way to cheat it to pass. The timing isn't "off", >> more likely you are running CHEAP gas and it's causing it to fail. The GA16DE series of engines has always had timing chains. The previous owner was either clueless or making it up. Perhaps an unscrupulous mechanic charged him for the magic "exchange" of chain for belt, which would be impossible to do. In any event, it is not what is causing your problem. I would look first at gas an oil. Don't use the cheap stuff. Retard the timing if that is what it takes to pass, and then set it back after the inspection. Your Catalytic converter is probably due for a changing. Stop using the cheap gas. It does far more harm than good. The few pennies you save will be spent in repairs due to the crud that the cheap stuff leaves behind. throttle body cleaning and EGR repair are temporary fixes. Do not cheap out with the $100 cat converter. You'll be sorry if you do. It is better to go to a reputable repair shop and get one that will guarantee the installation and the converter (no one will guarantee it will pass). The one you are offered is a remanufactured product, does not have to meet spec, and is not worth the time it takes to install it. Bobby > okay, let me give you more detail on my car so maybe you can tell more > about why "cheap" gas would causing it producing more HC & NO when timing [quoted text clipped - 7 lines] > replacement doesn't have anything to do w/ not passing smog, because the > car runs just fine. That isn't even possible.. > When the car didn't pass smog at Test Only Station this time, I took the > car to a garage and was told that I need to pay the mechanic $200 [quoted text clipped - 7 lines] > am confused about what I should do without emptying my wallet over this > little car. Maybe try putting some PREMIUM FUEL in it? > I would like to know the root cause of why this car is not passing smog or > is there no easy fix? Good grief, is switching to premium fuel for a couple of tanks too much work for you? Sorry I don't have time to teach you why low octane fuel causes the NOX to go up on older cars with carbon build up on the pistons. SignatureSteve http://www.atlantaracing.com I had a 93 sentra 2.0 se-r. After tune up & such, replacing the catalytic converter did the trick for me. (replacing the O2 sensor helped gas mileage, but not emissions) I'd do the cheaper/easier stuff first... Gary K > Hi All, > [quoted text clipped - 10 lines] > > Anson did you have the same problem as me which is high on HC and NO @ 15mph or no? >I had a 93 sentra 2.0 se-r. After tune up & such, replacing the catalytic >converter did the trick for me. (replacing the O2 sensor helped gas [quoted text clipped - 18 lines] >> >> Anson > Hi All, > [quoted text clipped - 4 lines] > barely met passing standard with HC(PPM) MAX:57, AVE:13, MEAS:57. The > NO at 25mph passed below AVE measured value easily. Try premium fuel. High NOX is related to detonation.. That or retard the spark about 10 degrees. SignatureSteve http://www.atlantaracing.com |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.