The code partially is "stamped" on the head.
a 1.8 dohc 16v engine is called BP, the 8v is called b8, b6 is for the 1.6 engine, z5 is for the 1994+ 1.5 dohc 16v engine, b5 is the 1.5 before this
I'm not sure but you may need to check the engine.
Check Auto Zone or Advance Auto, the codes are online.
Go to www.banzai-racing.com , it will tell you how to get the error codes and what they are.
No it is a non-interference engine
http://www.knizefamily.net/minimopar/fault/index.html there
no
My 1991 Mazda 323 has two plastic screws on drivers side, facing engine. Are they airbleeder valves?
There is nothing to "check". Look in the owners manual and change the belt according to the service requirements. They never "look" bad until they fail and destroy the engine.
A 1991 Mazda 323 typically has an engine oil capacity of about 4.5 quarts (approximately 4.3 liters) when including the oil filter. It's always a good idea to check the owner's manual for the specific engine type, as capacities can slightly vary based on the engine configuration. Make sure to use the recommended oil type for optimal performance.
ignition problem
At the EEC test port located by your power distribution box in the engine compartment - OBD I / EEC IV system - Helpfull
Chev LS6 T56