It’s fair to say that over 90% of our Honda swap inquiries we receive here at My Pro Street are about VTEC, how to wire VTEC, and questions about troubleshooting VTEC. To save some time and provide our members with a FAQ on VTEC, this Honda Swap VTEC Guide is born. Part 1 will focus on the SOHC D series as well as the DOHC B series engines from Honda.
Before you plan on swapping in VTEC honda swap however, check here for a guide on removing your Civic engine. This compilation is still a project moving forward, have some information or a correction you’d like to see added to our Honda Swap VTEC Guide? Leave us a message below and let us know!
VTEC How To – OBD1 SOHC Engine in OBD1 Honda Civic
Before we go over all the possible VTEC wiring options for a 1992-1995 Honda Civic or EG, note that all 1992 Honda Civics already have the VTEC solenoid switch run to the shock tower. Because this wire is already in place from your EG ECU harness to the passenger side shock body, all you will need is a Honda Civic 1992-1995 EX or SI engine harness to wire up VTEC.
The following instructions are operating on the assumption that you have a OBDI Civic with the matching OBDI ECU (P28 is recommended)
Additionally, you can also run the wires from your shock tower to the solenoid and VTEC spool filter to save yourself money and time.
1992-1995 Honda Civic CX – If you are using a P28 ECU, you need to wire both the VTEC solenoid and the pressure switch to your OBDI ECU. If your Honda Civic CX is not using a heated 02 sensor (four wire oxygen sensor) you will need to wire this as well. The engine found in this model is a D15B8 stock, and you will need the appropriate mount kit to complete your Honda swap.
1992-1995 Honda Civic DX and LX – Own a 1992 DX or LX? simply run the VTEC wire from your shock tower to your solenoid and switch to complete the VTEC wiring. You can of course always run wires from your ECU, P28 or P72.
1992-1995 Honda Civic VX – One of our personal favorites for the sheer fact that the VX is the lightest Honda Civic built in this generation, and could get up to 48 mpg before anyone knew what a Prius was. Already wired for VTEC, a OBDI Civic VX is the best donor chassis in this era of Honda Civic for motor swaps. The E-VTEC equipped D15Z1 is quite the funky performer, and you may need to rewire the special 02 sensor to convert from the wideband 02 that came stock, to the standard 4 wire narrowband oxygen sensor.
All 1992-1995 Mini Me Builds – If you are intent on keeping the SOHC alive, and you’re building a Mini-Me SOHC, you will need a VTEC pressure switch so that your P28 ECU knows it’s safe to trigger your VTEC cam lobe. The part number for this VTEC switch can vary, for SOHC VTEC models in the OBDI range the part number is 37250-PNE-G01.
VTEC How To – OBD1 DOHC B Series Engine in OBD1 Honda Civic
When upgrading to a DOHC B series OBDI engine, from the B16A3 all the way up to the B18C1, you’ll want to use a P28 or P72 ECU. Chipping your ECU will allow you to take full advantage of the EEPROM chip in your ECU.
1992-1995 Honda Civic EX or SI – When upgrading to a B series VTEC engine using this chassis, the VTEC is already wired and ready to rock and roll. If you are using a chipped P28 or have swapped your intake manifold, you may or may not need to wire the knock sensor. The knock sensor for the GSR engine is 30530-PV1-A01, and as stated, you can opt to bypass this by programming your chipping your P28 OBDI ECU.
1992-1995 Honda Civic DX and LX – Removing your D15B7 is easy enough and when you are swapping over to a DOHC B series, you need both the knock sensor as well as the IAB rewired to your ECU. When using a P72 ECU, this means that you must reuse the stock intake manifold. When installing a VTEC pressure switch, the B18C1 Honda part number is 37250-PR3-003, and it can be used across all DOHC engines.
1992-1995 Honda Civic VX – The only thing to change here when swapping a B16, B17, or B18 engine in your VX is to rewire your oxygen sensor to a standard four wire unit. Use our handy How To Guide here to get this rewiring job done in your Honda Civic.
1992-1995 Honda Civic CX – The last entry on our B series Honda Swap VTEC Guide is the CX Civic. Equipped with the D15B8, this car needs the VTEC wiring added to the harness, as well as the knock sensor and IAB wiring. You can alternately opt to use the B series engine harness and add the wires to your shock tower plug for a factory Honda look.
VTEC How To – OBD2 SOHC Engine in OBD1 Honda Civic
VTEC How To – OBD2 DOHC Engine in OBD1 Honda Civic
One of the most well known Honda engine swaps out there, the DOHC B series engine swap rounds out the last of the OBDI Honda Civics on our Honda Swap VTEC Guide. If you are looking for instructions on how to BAR legalize and smog your Honda swap, check our primer here. For simplicity sake, we’ll be lumping all OBDII B series DOHC Honda engines here, from the B16A2 all the way up to the B18C5.
1992-1995 Honda Civic EX, VX, and SI – This combination of Honda swap requires that you choose you ECU carefully. Use the factory P72, P30 or P2P ECU and you may have conflicting parts from your OBD2 engine to your OBDI chassis. VTEC is of course already wired into the chassis for these vehicles, but when you are swapping a DOHC engine in, you will need to retain your Z6 injectors for proper install. If you are swapping a DOHC B series into a VX, you should not re-use the VX injectors, you’ll need to go aftermarket or go with EX or SI injectors.
As with the OBDII SOHC examples, you will need to get creative with your intake pipe to mount and install an Air Intake Temperature sensor unless you’re swapping a B16. To use your B series distributor, you’ll need a flying loom that steps you up from OBDI to OBD2A or OBD2B. Use a OBDI B series alternator for the easiest and cleanest install and Honda swap.
1992-1995 Honda Civic DX and CX – Like the EX, VX and SI examples above, your choice of ECU matters here. Like the EX, VX and SI models, you will need to wire up a IAT solution as well as transfer injectors over. You can also choose to eliminate the crank position sensor if you so wish, as this won’t plug into your OBDI engine harness. If using a P28 ECU to drive your VTEC, bypass the knock sensor or secure the knock sensor harness out of the way.
If you are swapping a motor into your one wire CX Honda Civic, you’ll obviously need the 4 wire oxygen sensor from your choice of engine. This is a big part of our Honda Swap VTEC Guide and huge for you to complete your Honda engine swap.
VTEC How To – OBD2 SOHC Engine in OBD2 Honda Civic
1996-2000 Honda Civic DX, CX and LX – These non VTEC models will require the standard VTEC input and outputs. Wire up your pressure switch and VTEC solenoid when swapping your D16Y8. If you are keeping the P2P ECU and want to use that in your Honda Swap, it’s important to note that you cannot mix OBD2A and OBD2B harnesses.
Because of this reason, you’ll need to take extra care not to get stuck with the wrong engine harness or dash harness. Also make sure to identify what your Honda VTEC swap is, OBD2A or OBD2B, as all the wiring will be different at the ECU terminals.
You will also need to extend or lengthen your oxygen sensor wire, as this will move it primarily from the front header to the B pipe header outlet.
1996-2000 Honda Civic HX – Much like the VX of the previous generation certain HX models come equipped with Honda’s funky wideband oxygen sensor. Remember that you can use our guide to convert from 7 wire 02 to four wire 02 easily. Much like the DX, CX and LX above, the HX will require you to wire in the VTEC pressure switch and solenoid, and depending on the ECU you are using you may also need the knock sensor IF your Civic HX is a manual.
If the donor Honda Civic HX is an automatic, it will already have the proper knock sensor connector as part of it’s engine harness. When swapping in a D16Y8 it’s also good to note that you won’t need to change the IAT sensor as part of our Honda Swap VTEC Guide.
VTEC How To – OBD2 DOHC B series Engine in OBD2A Honda Civic
1996-2000 Honda Civic EX – Taking the step up from your D16y8 to a DOHC B series isn’t as hard as you might think. You will of course need the VTEC solenoid and pressure switch wiring. If you are retaining the OBD2A P2T or P72 ECU, you will also need to wire in the knock sensor. A chipped P28 can be used here if you wish to bypass the knock sensor, or you can alternately use a P30 ECU.
If you are swapping in a GSR engine, you will need IAB controls unless you are ditching the stock unit for a Type R style or aftermarket manifold (Skunk or BLOX). As with the previous listings, you will need the IAT relocated depending on the intake manifold you are using. If you are sticking with the stock B18C intake manifolds, you can simply convert to the round style IAT and install on the intake manifold runner.
1996-2000 Honda Civic DX, CX and LX – These non VTEC models have quite a laundry list of items you will need to successfully Honda swap your engine and have VTEC working. Obviously you will want the pressure switch and solenoid, but outside of that you will also need to convert the air intake temperature sensor from three wire to a two wire unit.
When removing your D16y7, you’ll find that our Honda Swap VTEC Guide will prove useful in getting your questions answered.
Like the EX above, if you are swapping in a B18C engine and sticking with the stock intake manifold, simply use the GSR IAT. Your secondary 02 sensor will also require lengthening or you may need an 02 adapter.
1996-2000 Honda Civic HX – The only thing that differs in this example from the DOHC to the SOHC is the knock sensor. Make sure to wire yours if you are retaining the stock ECU, or running a P72 or P2T Honda PCM.
VTEC How To – OBD1 Engine in OBD2 Honda Civic
Not smog legal and not exactly a common swap for those living in California or Arizona with stricter emissions laws. When swapping a OBD1 engine into your OBD2 vehicle, you must realize that the basic need are alternator and distributor. You can make the choice to convert from OBD1 backwards if you wish, for that guide click here.
SOHC D16Z6 Engine – You’re best served by running a chipped P28 ECU, but if smog is a real concern you’ll need to;
- relocate the air intake temperature sensor (or rewire to OBD1 unit)
- Transfer injectors
- Cut and splice in D16Y7 alternator plug
- Reuse OBDI distributor or simply convert
- rewire the idle air control valve.
- Eliminate or bypass all OBDII smog equipment
If you are swapping a D16Z6 into a Honda Civic HX, you’ll not only need the above action items but you’ll also need to ditch the crankshaft position sensor, as well as your EVAP purge and the downstream 02 sensor. Yes, your swap won’t pass smog.
If you are swapping this D16Z6 into a Honda Civic EX, the only change from the above items would be that the EGR will also need to be ditched and you will not need to mess with the VTEC solenoid or pressure wires.
That does it for our Honda Swap VTEC Guide, if you have any questions or comments please feel free to leave them below!