Understanding and Splicing Shielded Sensor Wiring

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Understanding and Splicing Shielded Sensor Wiring

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00:00	Shielded cables are commonplace with many of the mission critical inputs to your ECU.
00:05	Think engine speed, engine position and cam position sensors for example.
00:10	Using this type of cable does require an understanding of how we can work with and terminate the shield, whether that's add a dedicated shield drain pin on your ECU or perhaps you're passing the shield through an autosport connector.
00:24	In this lesson you'll see how this can be accomplished.
00:27	Alright, let's start with our reference and our sink wiring.
00:31	I've already cut these to length which is really obviously a pretty straightforward process.
00:36	I've got a tape measure here that I have just taped to my bench.
00:41	We're going to be doing a lot of measuring and cutting for all of our conductors, so it's always nice to just have this comfortably located there and we can confirm the length of each of our sections of wire.
00:55	So, the one I've got here in front of me at the moment, let's look on our overhead and we can see we've got a match mark of two on both ends of this.
01:04	Obviously, that is our second cable which is our synchronisation sensor.
01:08	We look at the other one here, we've got a single mark making this of course our reference sensor.
01:15	So, what we're going to do is get our sink cable out of the way for the moment.
01:19	Let's get started with preparing our reference sensor cable.
01:23	And what we want to do is begin by just stripping back some of the sheathing on the outside of this cable to reveal the shielded braid underneath.
01:32	And we want to allow a reasonable length here in order to have something we can work with, get our service loops and also when we are working with our Autosport connector, we need to be mindful of where all of our splices or solder sleeves are going to be located.
01:49	We've got quite a bit going on behind the back of this connector and we want to make sure, that everything's going to nicely fit within the boot.
01:58	Now, in order to help, and we'll be using this as a reference as we go through, if we look at our overhead camera here, I have printed out a template and I've basically, scaled this to suit our Autosport connector.
02:12	So, this just gives us a visual cue as to how much room we've actually got to work with where we are going to be comfortably protected or covered by the back of that heat moulded boot.
02:23	Alright, so let's get started and we're going to get our razor blade here.
02:27	What we're going to do is just straighten out a section of our shielded cable and we're just going to score the outside of our sheathing with our razor blade here, you can use a knife of course as well or instead of.
02:41	We don't need to cut too deeply here, we're just essentially scoring the outside of the sheathing and then by bending it backwards and forwards, probably a little bit hard to see, but that just breaks through that sheathing and we can now go ahead and cut down the length of the sheathing just to allow us to remove that and expose the braid underneath.
03:04	Again, not cutting too deep, we don't want to be cutting through the braid underneath that, so a little bit of care is required.
03:13	Once we've got that sheathing just scored, we should be able to pretty easily get through there with a fingernail and basically strip that off and now we've got our braid exposed underneath.
03:28	Now, we do need to understand what we're trying to do here and we're going to have to cut back some of that braid and if we just get our little solder sleeve into location, we can see how that should sit.
03:40	So, our solder sleeve that we've got here has a preinstalled drain as I've mentioned, otherwise, we can add our own drain and we want to essentially cut our braid back to approximately this location, so that our little red band of solder is going to be nicely central over our braid.
03:55	One end of our solder sleeve will shrink down on that outer sheathing, the other will shrink down onto our two cores of our shielded cable there.
04:05	So, what we're going to do is get that out of the way now and we can just gently push back on our braid there to expand it out and once we've done that, we can get in there very carefully with our flush cut pliers and we want to make sure that while we're doing this, we do not cut the conductors within.
04:25	So, it's a little bit of a process of just working our way around, care is always going to be helpful here and we can see it's pretty easy to get to a situation where we can then extract or remove our braid.
04:42	Alright, so at this stage with the majority of our braid removed, we can see we're still a little bit long which is always a good place to start.
04:50	What I'm going to do now is just use those flush cuts to trim us down until we've got just the right amount of braid exposed, let's go and get that done.
04:57	Alright, we've got our braid trimmed down here, just the right amount of braid exposed and if we get our solder sleeve alongside, we can see that that's going to fit really nicely there with our solder band nicely located central on our braid, exactly what we want.
05:13	Before we move on, I will mention there's a couple of ways we can work with terminating this braid using a solder sleeve and the alternative is to essentially fold that braid back up over itself onto the sheath beneath.
05:27	Now, the advantage of this is the sheathing is essentially semi rigid, so it provides a little bit more mechanical strain relief by doing this.
05:35	The downside of it however is it does produce a little bit more additional bulk.
05:41	Because we've got a lot going on behind this Autosport connector, I want to keep the bulk to an absolute minimum, that's why we're using this technique.
05:49	One last consideration here is now we've cut our sheathing off, our conductors below do not obviously have that mark that I made, so I'm just going to reintroduce that mark here just, so that when we splice these together, we're going to know which is our ref and which is our sink.
06:08	And I've made those marks a little bit back from the ends because chances are we will be trimming these to size and then we'll be stripping them and terminating them to our socket for our Autosport connector.
06:19	Alright, let's get our solder sleeve into location now, we'll bring in our heat gun and we'll get that shrunk down.
06:34	Alright, we've completed our ref cable there with our solder sleeve.
06:38	It is important when we are working with solder sleeves as well to ensure that we don't overheat the solder sleeve with our recovery, but we also want to ensure that that solder band has properly melted and wet out through our braid as well as our drain wire.
06:54	What we're going to do now is repeat that process with our sink cable, so let's get that done now.
07:01	OK, at this point we've got the ref and sink cables both terminated with our shield drain, so before we can go ahead and pin these out into our Autosport connector, we need to splice those two drain wires together.
07:15	So, let's just go ahead and have a look at one I've prepared ahead of time.
07:19	This is for our two knock sensor cables which are essentially arranged the same way with the shield drain shared.
07:25	And what we can see here is I've got a closed barrel splice that's located here and that's joining our two shield drains together and we've gone ahead and covered that with some STL that we've recovered down, so essentially this is exactly what we are aiming to achieve with our ref and our sink cables.
07:45	At the moment you can see that the drains are much longer than they need to be and we need to give a little bit of thought about where our splice is going to be located.
07:55	Now, we want to make sure that we've got enough room behind our heat moulded boot on the back of our Autosport connector and we do have, as I've mentioned, a number of splices going on here, so that all adds to the bulk.
08:09	What we're going to do is again essentially replicate what I've done here with our knock sensor wiring and we can see that the splice for our two drains is located reasonably close to our solder sleeves.
08:20	A consideration here we do need to be attentive of and this is an easy mistake to make is that if we trim these drain wires back too far, and this goes for essentially any wires where we do need to then strip the sheathing off, there is a limitation on how far we can strip that back or cut those wires back before we won't actually be able to get our wire stripper in there, so that makes things a little bit tricky, so always important to leave enough length for us to actually work with.
08:50	So, what we're going to do here is go ahead, trim these down and we'll get the sheathing removed, the insulation removed I should say using our wire strippers and we'll get those ready to install into our splice.
09:14	Alright, we've got our drain wires cut down and our insulation stripped and just to point when we are doing this, we do want to strip a little bit more insulation for engagement into our butt splice here than we would for our contacts.
09:27	So, in order to do this, just because we're only stripping three wires at this point, rather than resetting our little stop on our wire stripper, I've just moved that out of the way temporarily and if we just bring our splice into view here, we can see that basically got enough of the insulation stripped that we've got full engagement or at least really substantial engagement into that splice.
09:50	We don't want to be having any risk of not getting full engagement there and a good crimp.
09:55	Now, to complete this obviously we also need a third wire to come out of that splice which is our drain wire and for this I've just used a piece of that off cut that I stripped off before.
10:07	So, what we're going to do now is get everything located into our splice and we will then crimp that together, so let's get that done.
10:21	OK, we've got our three 22 gauge drain wires nicely installed into our splice and just before we go ahead and crimp this, we want to take one last look and make sure that we do in fact have full engagement with all three of those wires.
10:35	We do, we've got that splice just about butted up to the insulation, we've got a little bit of a gap there, we've got full engagement, so let's go ahead and crimp that down.
10:49	Alright, we've got our crimp completed, just a quick visual inspection of that, making sure that everything looks good, I can see my conductors at the end of that splice, we're all looking like we've got good engagement there, so that's going to be a nice reliable splice.
11:03	What we're going to do now is just cut a small section of SCL, 1 1 8th SCL would be a nice size to fit over that tightly and we're going to recover that down using our heat gun.
11:19	Alright, let's have a look at our finished splice under our overhead and we can see we've got our SCL recovered down nicely, it's important to make sure that it is extended past both ends of that closed barrel splice which it is.
11:32	I've just crimped down the open end of that, so it's essentially glued onto itself, so that's sealed now electrically and environmentally.
11:41	You can obviously see here I've got the drain wire coming out of this heading back in the direction of the cables and I've done this purposely rather than trying to feed the wires in from both directions and this allows me to then loop this back around, essentially creating a service loop and strain relief.
11:57	So, we're just going to essentially bend this back around on itself and head it back in the same direction as our other wires.
12:04	Alright, what we're going to do now is trim our conductors to length and we can terminate these with our sockets for our Autosport connector.
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12:34	You'll learn about Autosport connectors, how to select the right one for your application and how to correctly terminate them.
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