Greetings, i just bought a five-pin fault code reader from Draper off ebay new old stock, and tried to use it on a 2.0 sohc 8v non-catalyst pinto engine, and it didn't work. Then i tried it on a 2.0 catalytic car and it worked flawlessly, though it shouldn't work at all. Any ideas as to why it doesnt work as it should?