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Splicing to Shielding Braid

Practical Harness Construction - Club Level

Discussion and questions related to the course Practical Harness Construction - Club Level

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I am wondering, is there any risk of damaging the underlying insulation when using a solder splice?

Also I am planning a sub harness to add extra sensors to my engine, to connect to an aftermarket ecu (still using the factory harness for everything else)

I wanted to terminate this harness into a single plug, Deutsch DTM most likely, how would I deal with the shielded wire for the knock sensor in this instance?

G'day Royce.

The solder in the solder splices melts a bit easier than standard 60/40 solder, so while you do need to put some heat on it to get it flowed, its not as much as you might think. I've not had any problems with damaging any insulation when using them. Use quality ones though :-).

You'll want to splice out the shielded wire to its own pin, pass it through the connector, and splice it back to the shield braid on the other side.

from the data sheet on the raychem B-155-07 (TE connectivity) ones 'These controlled soldering devices are designed for termination of a bare or tin-plated copper shield on a cable having an insulation rated for at least +85°C.' so its safe to assume the solder melts/bonds under 85 degrees c.

An extra bonus question, If I wanted to break the knock sensor wire out into a separate plug in the cabin (for plugging in an external knock monitor) Is it possible that could introduce noise? it would only be probably 10cm long and spliced at the ECU plug.

All my experience with anything shielded is either car audio and 2 way radios, where things like this can cause havoc if done wrong.

Yes, I'd say you could be in danger of introducing noise there, as you're basically adding an antenna to signal wire. If you do it with shielded wiring though, and connect the shielding braid of the existing wiring, it should be okay, as any picked up noise will be drained away. Is it an OEM knock sensor? How many wires?

My plan was to do that, splice shielded cable for the tail, will be a Bosch 'Wideband' knock sensor, 2 wires.