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Old 02-05-2005, 01:51 PM
LI Sound Grunt
Senior MemberCaptains Club Member
Join Date: Jun 2001
Location: CT
Posts: 18,361
Default RE: Failed emissions test in NJ

Unfortunately, the gas cap test is the least automated part of the modern emissions test. There is lots of room for error in the test procedures themselves. The testor may choose the wrong "adaptor" or he may not tighten it all the way on the test rig. Add to that the fact that the testing equipment suppliers have sometimes made errors in making caps that weren't appropriate for certain vehicles as advertised. Furthermore, as the newer models are introduced with new designs and technologies, the "old" manuals (computerized or hardcopy) are sometimes not updated. This is one reason why CT does not check the newest model year vehicles.

That said - I have seen caps direct from the manufacturers on new cars properly fail. Without doing an investigation its hard to diagnose what happened in your case.

I think that very recently, the EPA has allowed the states to use only the OBD (computer - check engine light) test for the fuel evaporative system. Previously they only approved the mechanical test (take it off the car and put it on a test rig that pressurizes it to test the seal) since the OBD test only identified egregious failures. THAT said - a common cause of MIL (Malfunction Indicator Light) light illumination is not tightening the cap until it clicks. Just tighten the cap and after som many restarts the system should reset and light go out.

NJ probably also has an appeal or challenge system where you can get state people to do a re-check, if you think the garage is cheating or incompetent, or you have reason to believe there is nothing wrong with your car. There is probbaly a program web-site for details.

Not knowing anything else - get a Stant cap at a part store, the emissions station (if they do repairs) for your vehicle or an original equipment Part from the dealer.

I know much more about this subject than I really want too.... I could write a book about emissions testing..... actually - this is one of the reasons I retired early
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