I've been getting an occasional code 43 since day one of my B18b install. I just replaced the B18 with a B20 and now it's worse. The CEL comes on and it runs crappy. Mash in clutch and turn off engine then back on and CEL is gone and running fine. It didn't bother me before but now it's aggravating! Code 43 is "Fuel Supply System" or something similar. I've searched this and other forums without a definitative answer. My setup is: 90 Hf with 97 B20b4 running OBD0 with a 90 pr4, new 90 teg dizzy, OBD0 injectors. All 4 injectors check 2.3 ohms. All 4 plugs look the same, not ritch. DC Sports 4-2-1 one piece header with the O2 in a bung where 2 & 3 join. Greddy MX exhaust, no cat. I've substituted ECU's with another pr4. same results. Fuel filter is new, O2 is new, Dizzy is new. Anyone had experience with this?
TIA

 

possibly the fuel pump relay...or the pump is on its way out

 

i have the same problem with the b18a....bump for the same issue

 

Just thought I would follow up on my code 43. I had xenocron burn me a basemap chip for my socketed PR4. He spliced B-20 fuel and timing maps into the PR4 code. My car runs perfect! No code, no check engine light, no problems. I think the difference is having the correct fuel and timing to run your engine, that simple! I would certainly reccommend xenocron's service, he can socket your ECU as well.

 

I had a b18a with the same code, swap out the o2 sensor.