PRODUCT DETAILS
Rywire B/D Series Tucked Engine Harness - 1988-1991 Honda Civic and CRX (EF)
Doing a B series swap into your EF Civic or CRX? Trying to fix 30 year old wiring that's been cooked and hacked? This Rywire tucked engine harness is what you need. It's a clean, labeled harness for 1988-1991 Civics and CRXs that works with both B series and D series engines. You get the tucked engine harness plus the matching chassis jumper harness in the box, so everything plugs into your EF interior and shock tower connections the way it should. No more spaghetti monster engine bay or chasing weird electrical gremlins.
Made in the USA with Mil Spec Wire
Rywire builds this harness in the USA using Mil Spec Teflon coated wire rated to 200°C. That matters when your header sits an inch from your loom and you're actually driving the car hard. The budget friendly approach here is single black wire color and expandable loom instead of the full mil spec multicolor sleeving, but you still get brand new connectors, pneumatic crimps, clear labels on every branch, and pin to pin plus resistance testing. We use these harnesses on our own cars because they save time and don't create new problems that you have to troubleshoot later.
Includes Engine Harness and Chassis Adapter
Every Rywire B/D Series harness comes with the B1 base engine harness and the corresponding chassis jumper harness for your EF. The engine side covers all your sensors, injectors, and ECU connections. The chassis side plugs into your factory dash harness and shock tower connections. Rywire splits these into two pieces so you can move the engine side to another EF later if you want. Just grab the right adapter and you're set.
Pick Your ECU Type
This is the part that trips people up, so read it twice. Rywire makes this harness in OBD1 and OBD2 versions, but both versions use OBD1 ECU plugs (A, B, and D connectors). Here's what that means:
OBD1 Version (SKU: RYW-RY-B1-BASE-EF)
This version has OBD1 engine side wiring and OBD1 ECU plugs. Use this if you're running a Hondata, Kpro, or stock OBD1 ECU. Straightforward and simple.
OBD2 Version (SKU: RYW-RY-B2-EF)
This version has OBD2 engine side wiring but uses OBD1 ECU plugs, so you can run an OBD2 to OBD1 adapter harness if you need to. It will not support USDM factory OBD2 ECUs, but it does work with aftermarket ECUs that use OBD2 plugs and some non-USDM OBD2 computers. If you're running a Hondata or Haltech with an OBD2 adapter, this is the version you want.
What's Covered in the Harness
This harness includes connectors for all your engine sensors and components:
- Oil pressure sending unit
- Knock sensor
- Intake air temperature sensor (manifold style)
- Primary 4-wire oxygen sensor
- MAP sensor
- Throttle position sensor (TPS)
- Idle control motor
- Electronic speed sensor
- Radiator fan switch
- Engine coolant temperature sensors (ECU and gauge)
- Starter signal
- Reverse light circuit
- VTEC solenoid
- Power distribution cap
- Ground circuits
- OBD1 ECU plugs (A, B, and D) on both versions
- Injector, alternator, and distributor connections (based on OBD1 or OBD2 selection)
What's Not Included
Injector adapters, alternator adapters, distributor adapters, and charge harnesses are sold separately. Don't assume your oddball combo of engine and accessories plugs right in without adapters. Most B series swaps into EFs need at least injector adapters because the plugs changed between engine generations.
Modular Design for Future Swaps
The harness splits at the chassis jumper harness, so you can move the engine side to another EF later with the right adapter. This saves you from buying an entire new harness if you swap the engine into a different car or upgrade to a different chassis down the road.
What You Get
- Rywire B1 tucked engine harness
- EF Civic/CRX chassis adapter jumper harness
- Mil Spec Teflon coated wire rated to 200°C
- Brand new connectors with pneumatic crimps
- Single black wire color with expandable loom
- Labeled branches for easy installation
- 100% pin to pin and resistance tested
- Made in the USA
Fits Your Chassis
- 1988-1991 Honda Civic (EF chassis)
- 1988-1991 Honda CRX (EF chassis)
Works With These Engines
- B series engines (B16, B17, B18, B20)
- D series engines (D15, D16)
Available Options
- SKU: RYW-RY-B1-BASE-EF - OBD1 version
- SKU: RYW-RY-B2-EF - OBD2 version (uses OBD1 ECU plugs)
Note: Injector adapters, alternator adapters, distributor adapters, and charge harnesses sold separately. OBD2 version uses OBD1 ECU plugs and will not support USDM factory OBD2 ECUs.