I have a 94 Aerostar which I just took for state inspection. In New Jersey there is a new process where a test is done for excess nitrogen oxide. My van failed this test. When I took it to a mechanic he told me that the amount of nitrogen oxide released by the vehicle is related to the EGR valve. However my van does not have one. He said that he has only seen 2 other vehicles without an EGR valve and they were both Fords. He also said that neither of these vehicles was able to pass the emmissions test. Has anybody ever heard of this or have any suggestions....Sal

 

My 91 Ranger and my 95 Aerostar AWD both have the 4.0 engine and neither one has an EGR valve. I thought all newer cars and trucks had an EGR valve, so I was surprised to find that it wasn't there when I went looking to find it on my vehicles. The only reason I can think that Ford did not put one on was that they could meet emission standards without it. Most new cars and trucks use a three-way catalyst to reduce carbon monoxide, hydrocarbons, and oxides of nitrogen. (The EGR valve prevents the formation of oxides of nitrogen while the catalyst removes them after they are formed.) To do this effectively and meet the standards, the air/fuel ratio must be very tightly controlled. To figure out the air/fuel ratio, your engine relies on quite a few sensors (O2, coolant temperature, air temperature, mass air flow, etc.). Since your Aerostar can not meet the emissions standards, there is a chance that one or more of the sensors on your Aerostar is not quite working properly but not bad enough to set a fault in the computer. There is also a chance that your catalyst's performance may be degraded. Have your mechanic verify that all of these sensors, and the catalyst, are working properly before replacing anything. Another thing that might be worth trying is filling your tank up with a brand of gas that contains alcohol (Arco usually has about 10%) as alcohol burns at a lower temperature than gasoline. By lowering combustion temperature (which is what the EGR does) you will also reduce the formation of oxides of nitrogen. You might also want to try using a bottle of that stuff that helps you to pass emissions tests that you can get at the local auto parts store. By the way, what were the numbers for HC, CO and NOx that were measured during your emissions test?

 

My '95 also does not have an EGR valve nor a MAP. It is not due for inspection (NJ) until June BUT I have had a recent problem that probably would not let it pass the emission test. The check engine light kept coming on between about 40 and 50 mph. It also had a lot of pinging and ran like the timing was retarded. No distributor by the way. At any rate the mechanics(s)
changed air and fuel filters. Changed Ox sensor, decarboned the engine. Checked all the sensors. No help. I came across a site
that dealt with explorers and showed how to clean the MAS. I did
the procedure and THAT was the problem: A dirty mass air sensor.
http://www.glue.umd.edu/~singletn/web/pages/ping.html