I have a 1990 honda civic LX and i dont know where my crankshaft senser is at. Am also not sure if thats the problem, it gave me code 4.

 

its in dist.

 

Code 4 Crank sensor determines timing for fuel injection and ignition of each cylinder and also detects engine rpm.
Disconnect 6P connector on dist. [square] Measure resistance between two bottom wires. R should be 350-550 ohm. If not, dist is bad. If yes, check continuity to body separately each bottom wire. If yes continuity, dist is bad.