Hey guys, my buddy and I swapped in a 1.8L LS non VTEC dohc engine into his '98 EK hatch. We are using a Civic Si harness of the same year and using the LS ecu. It's throwing several codes and 2 of them I can account for because it has no O2 sensors hooked up yet. Here's the codes I pulled from the ecu with my scanner. P1509 Manuf. Control Vehicle Speed Idle Speed Control Aux Inputs <----------I have no earthly idea what that one means?? P0135 Heated O2 Sensor Malf. (Bank 1, Sensor 1) <--------- Know this one........ P1337 manuf. Control Ignition System or Misfire <-------- Have no idea either?? P0141 O2 Sensor Malf. (Bank 1, Sensor 2) <------- Know this one too........ The car idles reeeally really low. I'm talking like 450rpm. It also has a bit of hesitation on throttle tip in which I am attributing to the O2 snesors not working right. Also, we used another LS harness and it didn't have the right plugs to all the sensors on the B18A?? The Si harness has everything covered except of course the VTEC which this engine does not have, nor will the ecu look for. Any help at all is really appreciated. We're trying to get this thing running right. Just in case if you're wondering, the engine was practically given to him so that's why he used it versus a B18C. Thanx a bunch guys......... Edit.....the donor engie is a OBD1 engine.....1994 Integra. Could this be the problem?