Managed to finally get some more progress as parts arrived last week.   I soldered up the switching and regulator power supply using solder paste and heat plate which worked on all but one tiny chip. Solder bridged 2 pins but that was easy to clean up. I fitted both diodes backwards, one as didn’t check, the other I knew was backwards but was working off old schematic.   All voltages were good, so tomorrow I’ll add the can bus section and hopefully the micro controller.   I missed ordering the tiny capacitors for the canbus but the voltage sections are overly filtered and won’t impact testing. The static protection chip wasn’t ordered either as that want needed to test.

You may want to look at dielectric grease for those plugs. https://www.supercheapauto.co.nz/p/permatex-permatex-dielectric-grease-.33-oz/379868.html    

Also note   After alot of research im now unsure of TPS is even the problem Most OBD1 Code lists show  code 31 as Throttle Position sensor fault and code 43 is 43 Accelerator Pedal Switch which is different to Throttle Position sensor fault and idle switch  fault which is 42   I just checked and double decked the ECU Pinouot for Z4 Ecu and Stock BC5 Ecu and there is no wire or input for such 43 Accelerator Pedal Switch >_ <

Omfg so after checking every circuit in the entire harness, resistance testing &volt drop testing everything replacing alternator and battery   My power to earth connection short was my door switch wiring >_ < corrosion had caused both wires to touch causing a short, and the corrosion in the plug was so but it wasnt enough power to blow the fuse   Now reading OL (0) between  +ve lead when removed from battery and earth lead   Tps is still faulting, I let it idle for an hour with no fault code appearing drove it and code appears im going to bite the bullet and order a brand new one    

Last week I finally got the car running enough to go to Street Fighters, ran flawlessly to my surprise. Think I cracked the block though, I'll find out tomorrow.