I was recently given a 1990 Dodge Grand Caravan.
It has 209,002 miles on it. It has a 6 cyl. 3.3L Chrysler engine. When we took it to get an emissions test, it failed. The technician there suggested that it may be either the EGR valve or O2 sensor. I have heard that there is a way to test if the EGR valve needs to be replaced. I'm wondering if that is true, and if it is, how do I test it? Thanks so much for your help!
Is your egr valve a vacuum operated valve or is it electrical. If it is vacuum operated you can attach a hand vacuum pump to the vacuum fitting on the valve and apply a vacuum to see if the valve will operate though its complete distance. If it doesn't then you can remove the valve and check for carbon buildup on the bottom of the valve. If it is clean then the diaphram may be damaged. Second while you have the EGR valve off look at the port to see if it has alot of carbon buildup in it, if so clean the carbon out with carb cleaner to loose up the carbon. If it is electric the only two things you can really do is check the bottom for carbon buildup and do a resistance check of the solenoid valves(which will tell you if the solenoids windings are good, grounded(shorted) or opened(the internal wires are broken). If any problems are encountered with the valve change it out.