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Practical Wiring - Club Level: Step 8: Testing and Final Installation

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Step 8: Testing and Final Installation

09.27

00:00 - The eighth and final step of our HPA eight step harness construction process is the one of measuring and testing our harness to ensure that it does meet our design criteria.
00:11 Now we're going to undertake two steps to ensure this is the case.
00:14 We're going to physically measure our harness, comparing it to our layout document, and if those two match, we can be fairly certain it's gonna have a nice fit in the vehicle.
00:25 However having our harness fit nicely in the vehicle isn't going to do us any good if it doesn't perform the job we've designed it to do.
00:31 So we're also going to continuity test our harness from end to end, we're going to test that every pin makes a connection to every other pin where we know that it should.
00:41 To begin this process we're simply going to use our tape measure to measure the length of every harness branch and compare that to our design document and ensure that the two match.
00:50 Get my tap measure out here and we'll have a look at our MAP sensor connector branch 'cause that's nice and easily reachable out in front there.
01:01 And if I measure that, I've got a measurement of about 300 millimetres to the middle of that connector there.
01:10 Heading over to our document I can find out MAP sensor connector here, and I can see that that is meant to have a measurement of 300 millimetres, so we've got that one spot on.
01:21 The rest of the process is exactly the same so I'm gonna go ahead and measure the rest of the harness now, ticking them off on my layout document when I know they're correct.
01:45 Now that we've physically measured the harness and compared it to our design documentation, everything has come up pretty well there.
01:52 Everything is within a tolerance of I would say minus five millimetres to plus 20 millimetres.
01:59 I do like to put my tolerances a little bit higher on the plus side as it's always better to have a harness branch slightly too long than slightly too short.
02:07 Along with measuring all the harness branches, it was quite simple at that time to also just double check the orientation of all the branch exit points, meaning that when we run all these harness sections to the EFI system components to which they connect, they shouldn't have to cross over one another and we're actually going to end up cable tying a lot of these smaller branches together into one run that'll then branch out to those EFI system components and that's gonna keep things looking really tidy.
02:35 The next part of the process is our continuity testing.
02:38 And this is point to point testing which means we are simply going to pick a connector, choose a pin, and we're going to test that that particular pin connects to all the other pins that our design documentation says that it should.
02:51 We're then going to move onto that next pin in that connector and work our way through the harness testing every pin is connected to every other pin that it should be.
03:00 While you're doing this, you're going to want to keep a note on your documentation of where you're up to, as it is only necessary to continuity test these pins from one direction.
03:08 That means that if I test a particular pin from this connector connects to where it should on this side of the harness, I don't then have to continuity test from this side of the harness back.
03:19 Now this process is quite straightforward, we are gonna show a quick detailed example of it here, and then we'll go through and test the rest of the harness.
03:27 So I'm going to look at our ECU two connector up here, get my multimeter set onto continuity and we'll start with pin number one which was this pin here.
03:42 And have a look on our documentation and where that should connect to, which is our double throttle control solenoid signal.
03:49 So heading out to the other end of our harness we can find our double throttle control which is out of this branch, and there it is there.
03:57 So we've got our double throttle control connector here and we're looking at our signal line, or it's actually an actuator command line in this instance.
04:05 And that's going to be the white one here in the number two location.
04:09 And we can check that we've got continuity back to that ECU two connector on pin one.
04:15 Which we do, excellent, exactly what we're expecting.
04:18 The rest of the procedure is a rinse and repeat of this.
04:22 Once again keeping a note of where you were up to so you avoid testing the connections from both ends.
04:27 I'm going to get this done on our harness now.
04:56 We've got our testing procedure undertaken, I did actually manage to find one little mistake in there.
05:01 It was with our TPS connector.
05:03 It's actually got two signal wires, one is a wideband signal wire that spans the entire range of the TPS motion.
05:09 The other is a narrow band wire to give you a high resolution around the off idle zone.
05:15 Now we're not actually going to be using that narrow band signal but I had managed to get those two wires around the wrong way.
05:21 So I've gone ahead and corrected that error and everything else on the harness checked out fine.
05:27 So that's definitely one of the reasons we go through this testing process on the bench.
05:31 It's much easier to catch those errors and correct them now, rather than when we're bending over the engine bay of the vehicle.
05:36 Now speaking of the engine bay of the vehicle, it is finally time to head out there and get this harness in place.
05:42 We're then going to go through our final testing procedure which is going to be applying 12 volt power to the harness and going around with our multimeter determining that we do in fact have 12 volt supply wherever we need it.
05:53 And ensuring that there are no shorts to ground which we will know if all of our fuses stay intact.
05:59 We're out here next to the car now and it is time to get our harness installed.
06:03 The key thing you're going to need to take note of here is the direction from which you're going to install the harness into the vehicle.
06:10 Now our interior branches here have ended up quite bulky with our power supply module and our ECU connectors being quite large.
06:18 So it's not going to be possible to fit those through from the engine bay into the interior of the vehicle.
06:23 Instead we're going to approach the task from the other direction, we're going to take our engine bay side of the harness here and feed that through from the interior into the engine bay of the vehicle.
06:34 It is actually a wee bit slimmer once you get all these connector bodies through which you can do one by one, and that is going to make the process significantly easier.
06:43 On the middle of our harness here we are actually going to have a sealing grommet that is going to seal to the firewall of the vehicle.
06:50 Now the original sealing grommet was not supplied with the vehicle so we can't use that one unfortunately.
06:55 Instead we will source an aftermarket one that will have a split in it, allowing us to install it on the harness even though it has now been fully sheathed.
07:03 So now I'm going to contort myself under the dashboard on the passenger side of the vehicle there and get this wiring harness fed through into the engine bay.
07:12 By feeding the wiring harness through from the interior, we have managed to get it installed into the engine bay.
07:18 This is a little bit of a lengthy process and can sometimes be a wee bit frustrating as well.
07:24 But if you do it connector by connector, you will be able to get it into place.
07:27 We've routed it through the engine bay, referring back to the photos we took of the mockup harness that we made out of nylon rope.
07:33 And you can see it does actually have a nice tidy fit in the engine bay.
07:37 We've used cable ties to further organise the smaller harness sections, branching them out at different points along the main trunk of the harness to reach all the EFI system components.
07:46 You can see that as we pay particular attention to the orientation of these harness sections as they exit the branch points, we've minimised the number of cross overs in our wiring as those harness sections head off to the EFI system components.
08:00 The wiring heading to the EFI system components is forming nice gentle bends, we don't have any sharp right angles in there, and everything is still reasonably loose which means we don't have any strain on any part of the harness, which is definitely something we're looking for.
08:14 Now although I have plugged the harness into all of our EFI system components, this was reasonably necessary for the fitting process, I am now going to go and unplug all of these connectors, we're going to power the harness up for the first time and using our mulimeter or our LED test light, check that we have 12 volts where we expect to find it and all of our fuses have remained intact.
08:34 With our EFI harness now installed in the vehicle and everything tidily cable tied away, the harness construction process is complete.
08:42 What you're going to want to do now is plug in all of your EFI system components and power up the entire system for the first time.
08:49 Then probably check that you have communications between your laptop and your ECU.
08:54 Once that's confirmed, you're going to want to get into the sensor configuration and possibly the EFI tuning portion of your build.
09:01 Now we don't cover those in this course at all, but we do have our EFI tuning fundamentals and practical EFI tuning courses as well, which are gonna be a really good watch if that is something you'd like to progress on with.