95 Geo Tracker Emissions

[mr.b.fix-it]

I have a 95 Geo Tracker that I recently bought. I have foumd several problems. First, the egr valve had the side plug blown out of it and it leaked exhaust gas. Then the EGR modulator valve had a hole burnt through the top. Finally, the catalytic converter had gone bad and the guts went into the exhaust pipe and muffler. I have cleaned out the exhaust and put the converter back on with it being hollow like a test tube. I replaced the EGR valve and EGR Modulator valve with good used parts. Here is the problem. The service engine light is on and the computer readout is 51, which means there is a Emissions problem. I have tested for a vacuum and it does not seem like there is any vaccum to the EGR valve. I have also tested the EGR sensor which seems OK. I read in one of my manuals that the catalyic converter creates backpressure to create vacuum. Do you think I need to replace the converter. I was hoping not to if it is not the problem. We do not have an emissions test where I live.