Sycokid666

I'm sure it's been answered before and I have searched and searched and really haven't found an answer to the specific questions . So here is the setup I have a 93 VX hatch with a 99 ls motor running a 95 ecu in it now:
that im putting a 98 jdm b18c motor in . Now the questions are can I reuse the LS engine harness and put in on the jdm motor or use the jdm harness on the motor? Can i flip the harness around anyway , or is there a way just to use the ls harness and just splice the wires in the engine bay connections somewheres if so what wires do I splice for the vtec ? I'm thinking that since the car should be equipped since it is a VX model and did have vtec to begin with right? Or am I just totally confused and making it harder than it really is . Just some notes I did get a jumper harness to run the stock jdm odb2a ecu to the odb1chassis is there any other wiring I need to do in order not to throw any engine codes ? And what throttle cable do I need or can I use the ls cable ? Any help would be greatly appreciated I know these questions are probably basic swap 101 stuff but I am doing this by myself and don't really have anyone else that I can go to ask any questions ..Thanks...

JRCivic1

On the right side shock tower where the engine harness and chassis harness connect, there is a large grey plug that will have two orange wires on the chassis side (one is orange with a white trace, the other is orange with a black trace), and no corresponding wires on the LS engine harness side. This is where you would run the VTEC solenoid and VTEC pressure switch wires. The solenoid is connected to the orange/white wire and the pressure switch is connected to the orange/black wire. The second wire from the VTEC pressure switch goes to ground... an original VTEC engine harness terminates this ground wire at the main ground bundle on the thermostat housing.

No, you cannot use the JDM RHD engine harness in and just "flip" it over... you will be much better off starting with the LS engine harness and adding the wires needed for VTEC.

Good luck.

Sycokid666

Thanks JRCivic1 your info will help out tremendously that explanation is very clear .. I appreciate your help and thank you ..

Sycokid666

Having some issues on trying to use the ls harness , there is two sensors that don't have a home and also the type r block
has a sensor on the block on the back and this harness doesn't have a sensor connection for it and the tranny
speed sensor on the jdm block has a different connection
can I just cut the connection off of the jdm harness and use that one connection instead
another sensor is on the very top of the intake mani the harness has a connection but no home
and the last sensor is where the crank pully is a connection on the harness but not on the crank

JRCivic1

Speed sensor is on the transmission and not on the block. I am not sure what sensor you are referring to on the intake manifold, maybe some pictures would be helpful. The two wire sensor at the crank pulley sounds like an OBD-2 crank fluctuation sensor and this is not used on the OBD-1 chassis. The sensor on the back of the block may be the single wire knock sensor... and depending on what ECU you intend to use, it may or may not be necessary.

Please post pics and I can give you solid/accurate answers.

Sycokid666

Top sensor no home , using ls harness
Knock sensor using the plug off the jdm harness now need to wire
Crank sensor plug on the harness no plug in on jdm motor

Sycokid666

I'm Using the jdm ecu that came with motor and putting the motor in a 93 vx hatch ,using an ls harness , is there anyway I can wire a kS to a wire in the shock tower? And on the speed sensor the plug was different from the ls harness so I snipped the jdm connection off and stretched it so that one should be good . I was thinking the two sensors that are left hanging won't throw any codes since the ecu won't be looking for those right ?

Sycokid666

Is this the wire for my knock sensor?D3
There it is on the shock tower 10pin

JRCivic1

Your first pic appears to be the evap/purge solenoid plug... but unlike your other pics, the wire colors cannot be seen so proper identification can be made. In the future, photos of the plug style AND wire colors, or you share the wire colors in the post, would be the most useful. In any event, if the two wires are solid red and yellow/black, then yes it is the evap/purge solenoid plug. Unless you live in an area that requires an annual emissions check, tuck it away and forget about it. The second pic is the knock sensor and the third pic is the crank fluctuation sensor. The last plug will NOT be used in an OBD-1 application. Your wiring diagram appears to be accurate, so you would add the appropriate wires to the locations detailed in the diagram. For reference, the second wire at the VTP plug goes to ground... and the second wire at the IAB plug goes to 12v+.

I am not sure why your chassis already has a wire connected at D3... I would check continuity and make sure this wire doesn't go to something important before you cut it and use it for something else.

Your last pic of the chassis harness plugs shows an open hole for adding necessary wires. You can use these locations to make your wiring appear stock.