MetalGod Posted July 15, 2005 Report Share Posted July 15, 2005 I went for emissions today and to my surprise, I wound up failing. It turns out that the nitrus oxide level was somewhere in the range of 1100 or so...I'm not exactly sure how all that is measured and so on. I just took a quick look at the numbers and compared them to the numbers from the previous emissions test, which was before I bought the car back in 2001...sometime just before they got rid of emissions. Seeing as the nitrus oxide was only...225 or so the last time and it's about 900 higher now, it's clear there is a problem of some sort. Anyone have an idea what would cause that? If you need more information, I can take a look through the form again. Thanks for the help. Link to comment Share on other sites More sharing options...
KevinW Posted July 16, 2005 Report Share Posted July 16, 2005 What is the base ignition timing setting? Does the engine 'ping' on light loads? Any Diagnostic Trouble Codes? High NOx is usually a result of inadequate Exhaust Gas Recirculation or incorrectly set ignition timing (too advanced). Inspect the EGR tubes under the throttle blades for deposits and clean if necessary; there's plenty of information in the archives. I've attached an image of some recent emission test results for a 1996 DeVille Concours (83,000 miles) for comparison. ___________________________________________________ Link to comment Share on other sites More sharing options...
bigjayzway Posted July 16, 2005 Report Share Posted July 16, 2005 I would definately check your codes. My 94 passed with flying colors, and I didn't even have my O2 sensor in yet! These engines are great for emissions, even under bad conditions. You must have a serious amount of issues to fail! I too would check your timing, plugs, and wires! Big Jay Life is too short to grow up! Link to comment Share on other sites More sharing options...
figment3 Posted July 16, 2005 Report Share Posted July 16, 2005 my 96 failed 3 times,the answer to your problem and mine was to get the car hot,then take it in and tell them to run the test in 2nd grear,the rpms will be alot higher and the cat will work much better,this seems to be a problem with a lot of gm big moters,so in told Link to comment Share on other sites More sharing options...
adallak Posted July 16, 2005 Report Share Posted July 16, 2005 I went for emissions today and to my surprise, I wound up failing. It turns out that the nitrus oxide level was somewhere in the range of 1100 or so...I'm not exactly sure how all that is measured and so on. I just took a quick look at the numbers and compared them to the numbers from the previous emissions test, which was before I bought the car back in 2001...sometime just before they got rid of emissions. Seeing as the nitrus oxide was only...225 or so the last time and it's about 900 higher now, it's clear there is a problem of some sort. Anyone have an idea what would cause that? If you need more information, I can take a look through the form again. Thanks for the help. The thirst (and easy) thing to try is throttle body cleaning. The bores, the back sides of the blades and most importantly the EGR tubes in the TB. As soon as I cleaned them up with a stiff wire my 048 code and service engine soon light went off and emission was back to normal. I had similar numbers. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
MetalGod Posted July 19, 2005 Author Report Share Posted July 19, 2005 checked for codes...didn't find any so far. Link to comment Share on other sites More sharing options...
bigjayzway Posted July 19, 2005 Report Share Posted July 19, 2005 I talked to my mechanic about this... He said he has seen these pass by by-passing the egr valve solenoid. I am not sure on this one, but maybe SCOTTY or LOGAN will know? Big Jay Life is too short to grow up! Link to comment Share on other sites More sharing options...
adallak Posted July 19, 2005 Report Share Posted July 19, 2005 I talked to my mechanic about this...He said he has seen these pass by by-passing the egr valve solenoid. I am not sure on this one, but maybe SCOTTY or LOGAN will know? Big Jay Bypassing the solenoid might open EGR valve at light throttle since much more vacuum would be provided to the valve that way. But if it is stuck close it won't help. Perhaps you can pass emission test, but yoy wll have very unstable idle and an engine ready to stall. Do me a favore remove air duct, clean up the EGR tubes inside the throttle body, the bores of the throttle body and the back sides of two blades while you are on it. Your emission problem most likely will be gone and you'll pas inspection. Despite you do not have a related code and SES light your EGR system is plugged enough to make emission out of requirements. The code and light will show up some time soon, you do not need to wait for them. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Ed Hall Posted July 19, 2005 Report Share Posted July 19, 2005 I talked to my mechanic about this...He said he has seen these pass by by-passing the egr valve solenoid. I am not sure on this one, but maybe SCOTTY or LOGAN will know? Big Jay Also, retarding the timing as far as possible cleans things up a lot. It'll have less power than a 4 cylinder but it'll run clean. Link to comment Share on other sites More sharing options...
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