This article is meant to accompany all the info discussed in this video:
In this guide we will cover the tools needed, and some of the more technical aspects glossed over in the video.
Wiring a jumper harness is pretty straightforward and simple, just slightly tedious and can be done with minimal skills.
You will need the following:
- Soldering Iron
- Solder
- Heatshrink
- Snips
- Open Barrel Crimper
- Hot Glue gun (Or Potting Epoxy)
- ECU Pinouts
- Automotive Relay
- Wire
- Dead OBDI Ecu OR OBDI Ecu Header (If OBDII car, OBDII -> OBDI Jumper will make this substantially faster)
All said and done, ~$50-60 in supplies. This project clocks in at about 2-4 hours of work.
The Haltech ECU has just enough inputs/outputs to cover all the essential functions of an engine with some additional inputs/outputs leftover. If you build a harness for a full stock car, (A/C, P/S, distributor) you will have 1 analog input and 1 digital output (typically used for boost control) left over. In my experience, most performance hondas don't have A/C or P/S, but I've built the pinout and basemap around the idea of a fully functioning stock car. You can swap inputs in and out as you see fit. For example, if your car does not have A/C, you will be left with enough digital outputs to run Coil On Plug for example. The pinout is flexible, and I've included notes for several options you can change to build to your application as you see fit.
If you are building a racecar and need more inputs/outputs to run things like traction control, a suite of pressure sensors, etc. I HIGHLY recommend you look the way of the Elite 1500. The Elite 550 is an ECU that I would say is more comparable to a modern, updated Hondata S300 ECU.
There are several ways to wire a Haltech Elite 550 into an OBDI car, I won't cover them all, but using the information here, you should be able to apply the same basic theory and figure it out.
Your options are:
Create a Jumper using an OBDI ECU Header (That's what's covered in this guide, it makes the ecu easily removable if you change later on.)
Repin your existing engine harness to plug directly into the haltech. (this is a more permanent solution, you would not be able to plug another ecu solution in without rewiring. If you moved up to a haltech elite 1500, repinning is a breeze though)
If you have an OBDII car: Buy an OBDII -> OBDI Adapter Jumper harness, and repin the OBDI side to the 550. (this is basically just skipping the soldering and potting steps, much quicker and easier, will still need to do relay for vtec though)
STEP 1: PNP HEADER
The first step to building a PnP harness is to get the connector to PnP into. There are several ways to do this, At 5:10 in the video above, I go over how to remove the ECU header from an existing ECU. Most people will have a bad OBDI Ecu laying around that I'm sure they're looking to get rid of for cheap or free. You'll need to unscrew it from the board, then cut all the pins from the board itself to free the header from the board.
If you don't have access to a cheap or free ecu to pull a header off of, you can find them brand new at this link for $25.
After you've obtained an ECU header, you'll want to bend the pins out as flat as possible to make it as easy as possible to solder the connections for the wires.
STEP 2: SOLDERING AND PINOUT
Now that you've freed the header, you'll now need to solder wire to the corresponding pins.
For this step, I recommend cutting 33 equal length wires at 12" a piece. You'll also want to strip them all on one end ~1/3". I've created a visual guide for all the wires you'll need to solder. I would start by soldering a 12" wire to each of the magenta colored pins below. The easiest way to solder these wires to the pin is to 'tin' the wire with solder, then 'tin' the pin on the ecu with solder. Head the pin, and drop the wire on the pin. The tinned solder on the pin should heat up and melt the tinned solder on the wire forming a joint between the two. Once they have been joined together, heatshrink the connection.
Take note of the wires that need spliced, Before soldering those wires to pins, splice the matching wires together and ensure the final length of single wire on the end of the splice matches the length of the individual wires. For example, the ECU Logic/Sensor Grounds are 4 separate wires, they should all come together and output as 1 wire from the ECU Header as all these wires will be sending ground to 1 pin on the Haltech. Be sure to heat shrink your spliced connections.
STEP 2.1 VTEC RELAY
This should be obvious, but if your car does not have VTEC, you can skip this step.
After all the pins have been wired and all the wires have been spliced, you should be left with 26 wires headed toward the ecu (33 wires - the wires spliced into wire). The VTEC Solenoid is on wire A4. The VTEC Solenoid operates by being sent 12V power. The Elite 550 cannot send 12v output signal (The 1000/1500/2000/2500 can). It can only send a low side (ground) signal, so we will need to wire a relay to output 12v to the solenoid to activate.
Wiring the relay is simple. First, you will need to splice a wire off Honda OBDI Pin A25. (NOTE The diagram below says HALTECH A26). HONDA OBDI PIN A25 is the 12V power to the ECU from the engine harness. We will borrow power from the ECU to send 12v to the VTEC Solenoid. Please note, though this is a 12V power source, do not stack accessories on this line. At most, I would run a Haltech CAN wideband off this line before finding power elsewhere for accessories. It is not meant to hold a ton of load, but the VTEC Solenoid does not command much current.
With the spliced wire off A25, you should split it once again into 2 wires. We will use the 12v as a trigger for the relay as well as a power source for the vtec solenoid. The 12V splices from HONDA OBDI PIN A25 will go to 86 and 30 on the Relay. You will then take the HONDA OBDI PIN A4 to 87 on the relay. The final wire will come off the relay at the 85 position. This will will need to be cut to the same length as the other 25 wires, as this will be the one going to the ecu.
STEP 3 TERMINATE THE HALTECH ECU PINS
After the solenoid relay has been wired, you should now have 26 free wires. You might now notice that when you bunch these up, they're all different lengths. This is due to the horizontal spread of all the pins. So if you have a major discrepancy in lengths, now is your final opportunity to cut all these wires to the exact same length. If you skip this step, you will have a harness that will not lay flat, so make sure you do not skip this step.
Now that all the wires are the same length, our next step is terminating the wires and installing them into the plug on the Haltech ECU. This is where an open barrel crimping tool comes in handy. I know a ton of people 'crimp' there wires with pliers, but I'm here to make your life easy and keep you from having a wiring nightmare long term. Buy this. (It's $17, you can also get a ratcheting crimper with a die made to crimp in one hit for $33) Crimping wires is easier shown than explained in text, so check out the youtube video at about 12 minutes for an explanation and example of stripping crimping and putting these pins in the ecu.
Terminate all the wires with the supplied AMP Superseal pins in the Haltech kit.
Once you have terminated all the pins, go pin-by pin using the pinout available here. Reference the Honda OBDI Pin, find that wire, then place it in the corresponding receptacle on the Haltech Connector. This step is crucial to get right, so make sure you take your time and double, then triple check your work.
For this step, I print out the pinout and put an X beside each pin that I put into the connector. Then once all are in, I go back through the pinout, check the OBDI pin, see where it goes to the Haltech, ensure the accuracy, then circle the X I already made to verify that I've put it in the correct place.
If you get this wrong, you can damage your new ecu.
STEP 4 VERIFY BEFORE SOLIDIFY
This is one of the most important steps before we lock everything in. We're going to install the ecu and verify everything works correctly before finishing the harness.
STEP 4.1 PHYSICAL INSPECTION
Do a visual inspection of all the pins on the Honda Pin header. Ensure none of contacting each other whatsoever to avoid a short. if everything is clear, you're now set to plug the ECU into the car. Plug the whole ECU into the car.
STEP 4.2 CONNECT TO ECU
Key on. The LED should illuminate on the ECU. Connect your laptop using the included USB and open the Haltech Tuning Software (At time of writing this they literally just did a major update on the software, so steps may change in a very minor way). Hit the Connect Button (top left corner), the ecu will then load and populate. Should take ~45-60 seconds. You will then need to hit File>Upload Map, and upload our supplied map (included with purchase of the elite 550). The map is preconfigured for OEM Honda sensors and Trigger pattern.
It will prompt you to restart the ecu. Hit ctrl->F12, or key off for 3 seconds then key on.
STEP 4.3 TESTING INPUTS
All your sensor values will then populate. You're looking for several key things here. Check your Coolant Temp, Intake Temp, and Battery Voltage make sure they look sensible. If they read an extreme value, check those particular pins. Check your MAP, it should be reading ~0psi (+/- 1psi) *this assumes you have an OEM Honda MAP sensor*, if you do not you will need to calibrate the sensor. Check your TPS, make sure it goes up and down with the pedal.
Then go to the Haltech Main Setup (gear icon on the upper tool bar). Hit the 'Fuel' Tab at the top of the page. And check 'disable injectors'. Hit OK. The ECU will prompt another restart. Hit CTRL->F12, or key off for 3 seconds then key on.
Go to the Diagnostics tab. (If you dont have this tab, go to View>Load Page and Select whatever resolution and Diagnostics.page (Screenshot is grayed out because I'm not connected to an ecu)
This page will show you everything that's going on. Crank the starter over for 5-10 seconds while checking The trigger states. You're looking for it to say Running and Full. If the trigger reads Running and Full, The Haltech is reading the Distributor correctly.
Re-enable the injectors in the main setup once you've confirmed trigger settings.
STEP 4.4 TESTING OUTPUTS
Now we're going to test all the outputs to make sure they're correct. Hit the Main Setup gear. And Functions on the left. You'll now go through each individual function and test to make sure they work.
With Key on, click the function you want to test. Where it says 'active state', swap that from Low to High or vise versa, that will activate the item, then click apply. For example on Cam Control Switched, when you switch the active state to high, you should hear the relay you wired click the second you click 'apply'. Once you've verified it does, switch the state back to low and hit apply. Check the Cam Control Switched (VTEC), Check Engine Light (CEL turns on), Fuel Pump (Fuel Pump Primes), and Thermofan(fan turns on).
Boost control is a little more complicated to test. Select Boost control, then hit the boost control tab, set it to open loop. Hit okay. (car might ask to restart, do that). On the left, of the main screen, navigate to boost control->open loop base duty cycle. Set the entire map to 50%. Solenoid should start pulsing. If it does, set it all back to zero.
STEP 5 FINAL CONFIGURATION BEFORE FIRST START
Our included base map should have everything needed to start a car up with all oem honda sensors, but there are some minor things that need to be checked before the car is 100% ready for a first start.
5.0 Engine Calibration
It is essential that the ecu knows what displacement the motor is. Hit your Main setup, on the Main tab, under engine information, set your engine capacity to match the size of engine you have. By default, our supplied map is setup for a 1.8L B18 engine. If you have a D16/B16, set the displacement to 1600, B20, 2000cc, etc.
5.1 Trigger Calibration
By Default this map uses the Haltech suggested settings for a B18C Distributor. This should work for all B/D engines. I've found that with the H, you'll need to change the edge on the trigger and Home signal to rising from the default falling to run the engine, everything else can be left the same.
5.2 Fuel Calibration
It's imperative that you get this right. Select the fuel you'll be running. this map by default is set for all OEM Honda stuff on pump gas. If you're using E85, set it to ethanol petrol blend, and set the % to match whatever your E85 is. Base fuel pressure will be 43.5 PSI by default, if you're running an aftermarket regulator you need to make sure these numbers match. (if this is showing in a unit that isn't psi, you can change the units by hitting the ruler on the toolbar of the software and changing pressure units to psi/inhg)
5.2.1 Fuel Injector Calibration
If you're running aftermarket fuel injectors (Or H22 injectors which are bigger), you'll need to set the correct flow rate and deadtimes. On the main tuning page, scroll to the bottom and find Injection System. Expand that and open Stage 1. You'll then need to setup your dead time and flow tables to match the injectors.
5.1 TPS Calibration
Before first start, you need to calibrate the TPS. Go to Main Setup > Functions and select the Throttle Position Function. Hit the 'Calibration' Tab. Hit 'Start' on the TPS calibration screen and follow the instructions.
5.2 MAP Calibration
IGNORE THIS STEP IF YOU DO NOT HAVE AN AFTERMARKET MAP SENSOR
If you have an aftermarket MAP Sensor like a Hondata 4 Bar for example, you will need to calibrate that sensor.
If you have a Hondata 4Bar MAP Download This File
Save it to My Documents>Haltech>Calibrations.
Navigate to Manifold Pressure Sensor in the Functions Screen. Go to the calibration tab. Click the open folder, and select the file you just downloaded. The ECU will now be configured for the Hondata 4Bar.
STEP 5 STARTUP
After everything is configured, the car is ready to startup. Start the car and make sure everything reads correctly. If any sensors are reading erratically, check the wires to the harness or check the sensors themselves.
STEP 6 FINISHING TOUCHES
Once everything has been verified working, we just need to finalize everything. You'll notice there are a lot of pins left over that are unused. To avoid those pins ever shorting out, I recommend trimming them all off at the base of the connector so the only pins remaining on the jumper are the ones being used.
The last step is potting the connector (or sealing the wires for strain relief). You can purchase an epoxy potting kit here. Simply build a sealed wall around the connector with tape and poor the compound in until it solidifies.
For a budget solution, you can use hot glue and simple glue all the connected wires to the header to lock them in.
Congratulations, you've now successfully built a jumper harness from scratch and started your car on a standalone ECU system. This project gives you a more in depth look at how engine harnesses work and perhaps might inspire you to build your own from scratch one day.