Zip ties and a vice make it easy to hold the connector and then properly concentric twist the wires. We use a little bit of filler here to get nice flexibility and a nice round cable for shrinking.


Lap splices are properly crimped and glue-line shrunk.

Quality ECUs like the Haltech Elite 2500 have dedicated signal voltage reference for various sensors, as well as an isolated signal ground for ground reference. Since we were adding some new signals, we needed to tap into these existing +5V and signal ground lines. On this side of the sub-harness, we are actually splitting signal ground and +5V reference to go to the spares connector. If we ever add additional sensors they will need to use the same signal and ground reference as all of the others on the ECU. In other words, every sensor that is attached to the ECU should be using the ECU’s +5V and signal ground.


The DTM connectors on one end of the ECU bridge.

Here are the ECU and spares connections. The other side of the harness will be stuck into the Haltech’s A and/or B connectors. There will also be the small leg for the CAN bus as well as the wheel speed (SPI - pulsed input) leg.


The completed ECU and spares legs, nicely shrunk and glued.


Haltech’s ECUs use an AMP Superseal connector, which uses a different crimp tool, as it has standard “folded”-type crimps.
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Wednesday, January 10, 2018 1:16 AM
stupid question maybe but i have to ask ... why did you wire the can sensors that way ? It is a bus, so you can daisy chain sensors, no need to wire them all in paralel and join it all at the ECU. Or did i miss something ?
Wednesday, January 10, 2018 6:11 AM
So, we don't have any CAN "sensors" on this project, although such things do exist. I think you meant to say "devices" or similar, so I'll go with that.

When you think about a "bus", or parallel wiring, it's basically what we did.

Graphically it looks a little like this:


Sure, the ECU is the *, and we've split off in a few places, and we could have done something like:


Electrically they are equivalent. However, our circumstances made the former "split" style a little more preferable:

* We wanted a sniffing/resistor port near the ECU
* We were using the Haltech CAN hub at least for the WBC1/wideband
* The data logger was "over there", while the ECU and the WBC1 were sitting practically on top of one another.

We could have wired the ECU directly into Haltech's CAN hub, plugged the WBC1 into the CAN hub, and then made a cable to plug our logger into the CAN hub. If we needed a sniffing port, we could have plugged directly into the CAN hub as well.

This is the nice thing about CAN -- because it's a simple two-wire electrical bus, just about anything will work as long as you use quality twisted pair and appropriately handle termination resistance (either with the devices themselves or with actual resistors wired in at the correct location(s)).
Thursday, January 11, 2018 5:41 AM
Thanks for the explanation.
I knew it was equivalent, i was wondering why not use the convenience of daisy chaining the devices instead of wiring them like a hub. It makes sense to wire it as a hub if devices are not near each other :)
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