This is the first time my truck has failed and I don't have a clue what to do. It is really hard for women to trust a shop to not do things that are not needed. My truck read 1529 on Nox at high speed,1617 on Nox on low speed. It also failed HC at low speed with a reading of 157. Not 3 mos ago I just had a tune up with spark plugs, wires distributor cap, etc. done. Just had my oil changed yesterday. My blazer has 195,000 miles and I have owned it from its original owner, my previous boss, from 1996. I have taken excellant care of it. I do routine maintenance at the right miles,etc. I just feel so helpless because this has never happened and I don't know a trust worthy shop that won't rip a girl off . I paid over $300 for the tune-up but I had no choice as my truck was missing and shaking bad and I knew something was wrong and I had to get to my daughter out of town the next day so I just drove in to the closest shop by my work so they could fix it while I was at work. I don't know if this has anything to do with failing that test. Please help me as I love my truck and don't want it broken not to mention I really need to pass for the inspection.
Failed emissions for inspection on 1994 Chevrolet Blazer
by srfjdf143 in Webster, TX on April 25, 2009
ANSWER by jessgar , April 27, 2009
Sounds like a bad egr valve,nox is related. If egr valve is not opening,nox readings go way up. Why, the purpose of the egr valve is to cool down the chamber temp. Also on the other hand, the ecm controls the operation via the egr solenoid,the on and off vacuum send to the egr valve. Check operation of solenoid and check for related vacuum hoses