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Post by davefman on Mar 6, 2007 17:14:27 GMT -5
I'm thinking the egr valve is to blame for my not passing emissions. any idea where it is, if it is? I can't find it anywhere.
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Post by SUBIEJIM on Mar 6, 2007 22:54:11 GMT -5
davefman, As per stacks no EGR on MPFI cars. A couple of things to remember: High CO= Incomplete combustion (partially burned A/F mixture) Caused mainly from incorrect A/F mixture and or high engine temps. High NOx= Oxygen and Nitrogen in A/F mix combine at combustion temps over 2500 degrees and form NOx. Caused by high engine temps and or overly lean A/F mixture So....Check for the following.... Over advanced or retarded ignition timing. Both can cause High CO and NOx. Vacuum leaks..Check ALL vac hoses...Extra air entering the engine can cause High CO and NOx High cooling system temp..Check coolant level and the function of the system. I think you mentioned cleaning the injectors and de-carbonizing the engine so your good there....Carbon build up can raise combustion temps and pressures by artificially raising compression ratio. These are just a couple of things to check..I hope it helps. Let us know what you find out, Jim
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Post by davefman on Mar 8, 2007 11:27:02 GMT -5
thanks for the info. I think you're right about the rich mixture. I had an experianced mechanic at my work look at the failed emissions readings. He said that the high CO and low oxygen ratings indicate a rich mixture wich may result from a failing or failed O2 sensor. I also need to fine tune the throttle position switch. I had to order a new exhaust manifold due to the old O2 sensor being coldwelded in place. I also found a website that seems to have alot of the justy parts I can't find anywhere else, ie exhaust manifold. here's a link for anyone who's interested. www.trademotion.com/partlocator/index.cfm?siteid=214661
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