skudy

Hi,anyone got any ideas as to why a 1986 Astro should have a 1993-4 ECU fitted. The Van's VIN is definitely a 1986 and yet the ECU shows as ( Service No 16168625 BBMY ) and ( 16179411 BBMY ) which is the chip that's fitted. Everywhere I've looked says this is a 93-4 Astro ECU but it has been on the Van since I bought it 3 years ago and was working fine until recently. It was only after the ignition module blew that this came to light,as the Van blew 2 ignition modules one after the other,after about 20-30 minutes. It was originally showing a code 42 and a fuel pump fault code but after clearing them they never reappeared but still the Van will not start.The Alternator has also been replaced for a brand new one and all voltages are showing correct at the ignition module, coil ,etc. Can anyone explain why this should have an ECU from a totally different year fitted. Any help would be greatly appreciated.