Performing an engine swap, especially in Honda vehicles like the Civic and Integra, is a rewarding project for car enthusiasts. This guide provides updated and detailed information on what you need to consider when performing a B-series engine swap, with a particular focus on how an Integra Obd2 Scanner becomes an indispensable tool in this process.
Understanding OBD2 and Engine Swaps
OBD2 (On-Board Diagnostics II) is a standardized system that allows you to access vehicle system information for diagnostics and monitoring. When you’re swapping engines, especially across different generations (like installing an older OBD1 engine into an OBD2 chassis), understanding OBD2 compatibility and potential issues is crucial. This is where an Integra OBD2 scanner comes into play, helping you diagnose and troubleshoot any electrical or sensor-related problems that may arise during or after the swap.
Acronyms to Know
Let’s start with some common acronyms to make this guide easier to follow:
- OBD2a: 96-98 Civic / 96-99 Integra
- OBD2b: 99-00 Civic / 00-01 Integra
- EWH: Engine Wire Harness
- VTS: VTEC Solenoid
- VTPS: VTEC Pressure Switch
- KS: Knock Sensor
- IACV: Idle Air Control Valve
- Dizzy: Distributor
- PnP: Plug n’ Play
Engine Swap Essentials for 96-98 Civics
Whether you’re installing a B16, B18, or B20 VTEC engine in your 96-98 Civic, the foundation is ensuring correct component compatibility.
Mounts and Brackets:
For 96-98 Civics, consider using 99-00 Si engine brackets for optimal fit:
- Front transmission bracket
- Rear engine “T” bracket (99-00 Si or JDM EK4/9 “T” bracket is recommended over Integra “T” bracket)
- A/C bracket
- Left (driver side) dual-post engine block mount (only if using a B18 engine)
Alternatively, 94-01 Integra brackets can be used:
- Front transmission bracket
- A/C bracket
To retain A/C, use a “P54” 94-97 Delsol DOHC VTEC or CRV A/C bracket.
Reuse these stock Civic brackets:
- Top transmission mount
- Left (driver side) dual-post bracket
Shift Linkage:
For 96-00 EK chassis, a 99-00 Si or JDM EK4/9 shift linkage is highly recommended for proper shifter centering. 94-01 Integra linkage may cause the shifter to sit too far back.
Axles:
Compatible axles include:
- 94-01 Integra (all 5-speed models, JDM or US)
- 99-00 Si
- 94-97 DOHC Delsol
Wiring: Part 1 – Harness Considerations
For 96-98 Civics, reuse your existing Engine Wire Harness (EWH) or use a 96-98 EX 5-speed EWH. OBD1 EWHs are incompatible with OBD2 Civics due to their 2-piece design versus the 1-piece design of EK Civics.
Remember, OBD2a (96-98 Civic) and OBD2b (99-00 Civic) wire harnesses are not interchangeable.
Compare OBD2a and OBD2b Harnesses
If you have a non-VTEC Civic and are installing a VTEC engine, you’ll need to modify your EWH:
- Add VTEC wiring (VTS & VTPS).
- Wire in the Knock Sensor (KS).
- Perform the IACV mod (converting from 3-wire to 2-wire IACV plug).
VTEC Civic (like 5-speed EX models) EWHs are more convenient as they already include VTEC and KS wiring. However, the 2nd 02 sensor wiring is part of the cabin harness in EX models, not the engine harness. This is important if you plan to use a US OBD2 ECU, as you’ll need to manually wire in the 2nd 02 sensor. OBD1 ECUs do not require a 2nd 02 sensor.
For non-VTEC Civic owners hesitant about wiring, using a 96-98 5-speed EX EWH is a good option. Ensure it’s a 5-speed harness, not an automatic one.
Wiring: Part 2 – Essential Modifications
To use an OBD1 engine in an OBD2 Civic, further wiring modifications are needed for the distributor, injectors, alternator, IAT, and CKF sensor.
(1) Distributor Plug:
- Option 1: Cut and splice OBD1 distributor plugs onto your OBD2 EWH, matching wire colors.
- Option 2 (Easier): Use an OBD2 B-series VTEC distributor (96-00), which is PnP with your 96-98 EWH.
(2) Injector Clips:
- Option 1: Cut and splice OBD1 injector plugs to your OBD2 EWH, matching wire colors.
- Option 2 (Easier): Use OBD2 injectors (96-00, B-series or D-series) for PnP compatibility.
- Option 3 (Alternative): Modify OBD2 injector clips by removing the blue cap and securing the clip onto the OBD1 injector with a zip tie.
OBD2 to OBD1 Injector Clip Modification
(3) Alternator Plug:
OBD1 alternators use a round plug, while OBD2 alternators use a square plug.
- Option 1: Cut and splice an OBD1 alternator plug to your OBD2 EWH.
- Option 2 (Easier): Use an OBD2 B-series alternator (96-01) for PnP.
- Option 3: Swap the inner plug of an OBD2 alternator into the OBD1 alternator.
(4) IAT Sensor:
OBD2 and OBD1 IAT sensor plugs are different.
- Keep your OBD2 IAT sensor and drill a hole in the intake arm.
- Cut/splice the OBD1 IAT plug to your EWH to use the OBD1 IAT sensor on the intake manifold runner.
(5) CKF Sensor (Crankshaft Position Sensor):
For US OBD2 ECUs with OBD1 engines, a CKF sensor workaround is needed. US OBD2 ECUs expect a CKF sensor on the oil pump (present in US OBD2 engines but not OBD1 or JDM OBD2 engines).
ECU Options and OBD2 Scanner Use
Choosing the right ECU is critical. Here are ECU options and how an Integra OBD2 scanner fits into each scenario:
(Option 1) JDM OBD2 ECU:
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Pros: Easiest solution, PnP with EK chassis, doesn’t require VTPS.
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Cons: Limited upgrade options, may not pass smog due to incompatibility with US OBD2 scanner tools, 115-120mph speed limiter.
Using an Integra OBD2 scanner here would reveal communication issues during a smog check, as JDM OBD2 ECUs are not designed to communicate with US OBD2 diagnostic tools.
(Option 2) OBD1 ECU Conversion:
Use an OBD2a to OBD1 jumper harness and an OBD1 ECU (like a reprogrammed P28).
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Pros: OBD1 ECUs are easily programmable, don’t require 2nd 02 or CKF sensors, and are less sensitive than US OBD2 ECUs.
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Cons: Will not pass smog, VTPS wiring is required.
In this setup, the Integra OBD2 scanner will likely not be fully functional, as you are bypassing the OBD2 system by using an OBD1 ECU.
(Option 3a) US OBD2 Spec (OBD2a):
Use a 96-97 DOHC VTEC Delsol P30 ECU, 96-99 Integra P72/GSR ECU, or 96-98 P73/ITR ECU.
(Option 3b) OBD2b Conversion:
Use an OBD2a to OBD2b jumper harness and a 99-00 Civic Si ECU.
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Pros: Can pass smog (with successful CKF bypass in Integra or Civic Si chassis), potentially pass smog for B-series BAR’d Civic cx/dx.
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Cons: 2nd 02 sensor needs to be wired and functional.
An Integra OBD2 scanner is essential here for ensuring smog compliance. It can verify that all OBD2 systems are functioning correctly, including the 2nd 02 sensor and the CKF bypass (if applicable). It can also help diagnose any codes related to the engine swap.
Considerations for 99-00 Civics (OBD2b)
Engine swap information for 96-98 Civics largely applies to 99-00 Civics.
Wiring (99-00 Civics): Part 1
Similar to 96-98 Civics, but with key differences:
- For non-VTEC to VTEC swaps, you need to add VTEC wiring, KS wiring (unless using a P28 ECU), perform the IACV mod, and change the distributor plug to a larger style (99-00 Si, 96-98 Civic, or 96-01 Integra).
Honda used a smaller distributor plug on 99-00 SOHC Civics, requiring this change when reusing the SOHC EWH with an OBD1 engine.
Switching to a 99-00 Si EWH is recommended, similar to using an EX harness in 96-98 Civics. Again, the 2nd 02 sensor is part of the Si cabin harness.
Wiring (99-00 Civics): Part 2
Wiring information from 96-98 Civics applies here as well.
ECU Options (99-00 Civics) and OBD2 Scanner Relevance
(Option 1) 99-00 Si ECU:
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Pros: Easiest solution, PnP for 99-00 EK, compatible with US OBD2 scanner tools, potential smog pass (depending on variables).
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Cons: CKF bypass required, limited OBD2 ECU reprogramming, 2nd 02 sensor required.
An Integra OBD2 scanner is vital for confirming the CKF bypass is working and for general diagnostics and smog readiness checks.
(Option 2) OBD1 ECU Conversion (99-00 Civics):
Use an OBD2b to OBD1 jumper harness and an OBD1 ECU (like a reprogrammed P28).
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Pros & Cons: Same as OBD1 conversion for 96-98 Civics.
OBD2 scanner functionality will be limited here, similar to the 96-98 Civic OBD1 conversion.
(Option 3a) US OBD2b Spec:
Use a 99-00 Si ECU or 00-01 Integra GSR/ITR ECU (requires immobilizer removal).
(Option 3b) OBD2b Conversion (using OBD2a to OBD2b harness):
Use a 99-00 Civic Si ECU with an OBD2a to OBD2b jumper harness.
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Pros & Cons: Same as OBD2b conversion for 96-98 Civics.
The Integra OBD2 scanner is crucial for smog checks and verifying system health with US OBD2b ECUs.
(Option 4) JDM OBD2 ECU (99-00 Civics):
Use a JDM OBD2 ECU with an OBD2b to OBD2a jumper harness or a JDM CTR (PCT) ECU (OBD2b spec, PnP).
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Pros: (Inconsistent information in original text – assuming similar to 96-98 JDM ECU).
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Cons: Requires OBD2b to OBD2a jumper harness, will not pass smog, 115-120mph speed limiter.
Similar to 96-98 JDM ECU, the Integra OBD2 scanner will show communication issues during US smog tests.
OBD2a/OBD2b Integra Engine Swaps
Engine Installation (Integra):
Reuse all existing engine brackets, mounts, axles, and shift linkage.
Wiring (Integra):
Reuse existing EWH and follow wiring guidelines for 96-98 Civic for 96-99 Integra, and 99-00 Civic for 00-01 Integra.
Alternative Wiring (Integra): OBD1 EWH
Surprisingly, you can use a US OBD1 engine wire harness in a 96-01 Integra due to the 2-piece harness design being backwards compatible.
Compatible OBD1 VTEC EWHs:
- 94-95 Integra GSR
- 92-95 Civic Si/EX
- 93-95 DOHC Delsol
For non-VTEC Integras using an OBD1 EWH, ensure VTPS, VTS, and KS are wired from the ECU plugs to the shock tower plug.
ECU Options (Integra) and OBD2 Scanner Importance
Note: 96-01 OBD2 Integras have the 2nd 02 sensor in the cabin harness. 00-01 Integra ECUs have immobilizers.
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(96-99 Integra) JDM OBD2 ECU: PnP. Same pros/cons as 96-98 Civic with JDM ECU.
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(00-01 Integra) JDM OBD2 ECU: OBD2b to OBD2a jumper needed. Same pros/cons as 96-98 Civic with JDM ECU.
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(96-01 Integra) OBD1 ECU Conversion: Same pros/cons as 96-00 Civic OBD1 conversion.
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(96-99 Integra) OBD2a US ECU: PnP. Same pros/cons as 96-98 Civic.
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(00-01 Integra) OBD2a US ECU: Same pros/cons as 99-00 Civic.
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(96-99 Integra) OBD2b US ECU: OBD2a to OBD2b jumper needed. 00-01 Integra ECU requires immobilizer removal.
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(00-01 Integra) OBD2b US ECU: 99-00 Si ECU is PnP. Pin A15 to A16 move for fuel pump with 00-01 Integra ECU. Immobilizer removal or bypass chip needed for 00-01 Integra ECU.
Across all Integra ECU options, an Integra OBD2 scanner is valuable for diagnostics, smog checks (when applicable), and verifying the correct ECU operation post-swap. It becomes particularly critical when using US OBD2 ECUs and aiming for smog compliance.
Conclusion: The Role of Your Integra OBD2 Scanner
Performing a B-series engine swap in your Honda Civic or Integra requires careful planning and execution, especially concerning wiring and ECU compatibility. An Integra OBD2 scanner is not just a tool for post-swap diagnostics; it’s an essential companion throughout the process. It helps you:
- Verify ECU Compatibility: Ensure your chosen ECU is communicating correctly with the vehicle’s systems.
- Diagnose Wiring Issues: Quickly identify any sensor or wiring problems that arise during the swap.
- Confirm Smog Readiness: Check if your setup is compliant with OBD2 smog regulations, especially when using US OBD2 ECUs and aiming for legal street use.
- Monitor Engine Health: After the swap, use your scanner to regularly monitor engine parameters and catch potential issues early.
By understanding the nuances of OBD2 systems in Honda Civics and Integras and utilizing an Integra OBD2 scanner effectively, you can navigate your engine swap project with confidence and ensure optimal performance and reliability. Remember to consult wiring diagrams and seek expert advice when needed for a successful and enjoyable engine swap experience.
