I got a 93 civic hatchback and im putting a 90 LS into it and the mechanic said i could still use the 93 ECU and was wondering if thats true and will the car run right

 

Technically you can, but it's not a good idea to do it for a long time. The fuel and ignition timing maps will be for the SOHC 1.5 or 1.6L engine, and you'll be running a 1.8L DOHC engine, so the maps will be completely wrong. Eventually you will damage the engine, from running so lean (among other things). You should find a '92-'93 LS ECU, since it's such a similar engine and it's OBD1 so it will plug right into your car. Or get your stock ECU chipped with the base map for your new engine.

 

hondaspoon is dead on

 

X2!

 

ok i also forgot to mention that the civic is automatic and im making it stick so regardless im better off getting the ecu. Would the 90 ls ecu work

 

no