1996 Nissan 200SX Timing

I have a 96 200sx 1.6L that awhile ago I replaced the timing chain on and assembled it correctly and i marked the distributor to make sure the timing was right. The car ran perfect once everything was back together and a little over a year later it needed to be smogged. they told me it had failed the mechanical portion of smog because they could not find the timing marks on the pulley and their machine was throwing out some crazy numbers as if my pulley was on wrong or my distributor was 180 out. The pulley only goes on one way and the distributor was on correctly. I felt like that was b.s. so i went home and tried to time it myself. Same thing happened I couldnt see the timing marks with a timing gun even though they were on the pulley. So i checked the marks with the engine off when piston 1 was at tdc and there were no timing marks. I went to pick n pull and aquired a new pulley from a 97 200sx and it turns out the timing marks are about 100 to 110 degrees below where the marks were on my stock pulley. So i threw the pick n pull pulley one on and boom the timing marks were there when timed with a gun and by checking #1 piston at tdc. So i checked the timing and made sure it was 8 degrees below tdc. It was and was running good. I took it to get it resmogged and it failed again. This time their computer said the timing was 41 degrees btdc even though i just timed it to 8 degrees btdc. I have no clue how that could happen and it seems to me like it is either a sensor or ecm problem but im not sure. Do you know what could be wrong? Thanks for your help.