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Practical Standalone Tuning: Step 2: Trigger Setup

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Step 2: Trigger Setup


00:00 - The next step of our 10 step process is to configure our trigger inputs, and these are the most critical that the ECU relies on.
00:07 Essentially all of the calculations for fuel and ignition delivery are based around the trigger inputs, namely engine speed and engine position.
00:17 So it's absolutely essential that these are exactly what they should be so the ECU knows what's going on, knows what the engine RPM is and knows what the engine position is and if we don't have that right, chances of getting the engine to start and run correctly are dramatically reduced so let's have a look in our software here and see what we're dealing with.
00:37 So we'll start by pressing the escape key and we want to cycle down this time, understandably here to our triggers menu.
00:45 So we'll just expand that and see what we're dealing with.
00:48 We'll start with our trigger setup and again thanks to our base map we should already be good to go here.
00:56 Our first option here is our trigger mode which you can see is already configured here to Subaru version 7-10 JDM.
01:05 Let's double click on this though and there is a fairly significant and long list of factory trigger modes for a pretty wide variety of generally popular vehicles or engines for use in the aftermarket so most will be covered there.
01:24 Other than that, if you're doing something custom, there are multi tooth modes, so you can actually set up your own custom trigger pattern as well.
01:33 In this case though, we do need to use the correct trigger mode.
01:37 Not just because of the operation of the engine but this will also cover the variable cam control strategy as well so basically just by choosing that mode, it already prepares the ECU to understand how many teeth, any missing teeth etc it's likely to see from the crank trigger in this instance, as well as our cam position or synchronisation input as well.
02:01 Alright so that's our main setting, again very very easy.
02:05 Our RPM filtering here, you can see that that is set to level one, which is as it says, default, we've got the ability here to go level one through to four.
02:15 With any filtering, it's always a good idea to start with the absolute minimum amount of filtering possible and then only add filtering if you are actually striking issues.
02:27 The Subaru trigger pattern actually has proven itself to be incredibly reliable and resilient, it's not really prone to a lot of noise so really should be no need to actually change this.
02:37 If you are having problems with noise, I would be considering looking at your wiring before you're worried about trying to fix it with a bandaid by adding filtering.
02:48 OK so that's our main setup there, basically prepping the ECU for what it's expecting to see.
02:53 Let's press escape here and we do have options here for trigger one which is our engine speed and trigger two which is our engine position so let's have a look at those individually.
03:02 We'll expand out trigger one and we'll click on that.
03:05 So trigger one type, so what type of sensor are we using here? Subaru use reluctor so it is set up to reluctor or magnetic sensor would be the other term of that.
03:17 We'll double click and we can select this to be a reluctor, a magnetic sensor in other words or an optical/hall sensor where we're looking at a digital style signal.
03:27 So that's done there.
03:29 Again we've got the ability to add filtering to this and just as I explained with the other filter that we looked at, we really want to use as little as possible and again should be no need with the Subaru trigger system to change that.
03:42 Arming threshold table, this is a little bit of a tricky one with the reluctor setup.
03:46 So the reluctor, or variable reluctance magnetic sensor, the element here is that the amplitude of the signal is going to depend on the engine RPM so we do need an arming threshold table which will tell the ECU when the voltage has exceeded that threshold so essentially when it should be expecting to look for a zero crossing trigger.
04:07 So we can see that at low RPM, we've got a 0.5V threshold, at higher RPM we're up at 3V so this again by default should be sufficient.
04:18 I have had situations where when I went to crank the engine for the first time, I wasn't seeing any RPM at all.
04:25 And on the odd occasion we may find that particularly down at that 500 RPM break point, we need to drop the arming threshold down to maybe 0.1 - 0.2 of a volt.
04:35 It's a balancing act because the arming threshold is designed to ignore background noise on that input so we don't want it too low or we could end up falsely triggering but too high and the ECU will essentially ignore valid signals so again this should be a pretty good starting point and should also be a pretty good starting point for just about any variable reluctor sensor, irrespective of the engine type.
05:01 Now let's come down here to trigger two and what we're going to see is essentially exactly the same, we've got all the same options here, the type of sensor, reluctor or optical/hall, the filtering and then the arming threshold so we won't dive into that in any more detail.
05:17 One element I will deal with here, if we come down here to the calibrate, we're going to see this in action but this allow us to actually calibrate the ignition timing so that we're going to be seeing the same timing on our laptop screen that the engine is actually being delivered.
05:32 This requires the use of a timing light and we'll deal with this independently in a separate module.
05:38 Alright so before we do move on, I will just show you how to use the trigger scope function which is a really great option in the G4 range of ECUs.
05:49 We can access this from the ECU controls menu, you can see that that option is right down the bottom.
05:54 Before we do that though, it's going to require us cranking the engine and at this stage I don't want the engine to start so let's come back up and just make sure that that's not going to happen and to do that, we'll come to fuel main and what we're going to do is just temporarily turn our fuel off, so this is just going to make sure that the ECU won't actually try injecting fuel.
06:15 We'll just store that change temporarily and we'll click back down to our trigger scope.
06:20 This is essentially an oscilloscope and at the moment we've got some garbage here that's been captured without the engine cranking.
06:27 So we've got, at the top in green, this will be trigger one, our engine RPM input and below this we've got trigger two, can actually see that there is a legend there, a label for that which will be our engine position.
06:40 So what we're going to do here, I'm going to crank the engine and as soon as it starts cranking, I'm going to click that little capture button and crank it for a few seconds so let's do that and see what we've got.
06:55 Alright so we can see we've got data here, little hard to sort of really make too much sense of this but we can manipulate this just like our data log so here I'm just using the upper arrow and by holding down the shift and left and right arrow, we can make sure, manipulate this and move around.
07:13 So we can see that we've got our main engine RPM signal.
07:17 We can also see that the polarity of that signal is correct.
07:21 Easy to see with our trigger two down the bottom here and essentially while it does look a little bit noisy, what we've got is our traditional pulse, shape I should say, to our reluctor input and that is a correct polarity there so it's going to trigger on that falling edge so absolutely everything is looking good here, we can also use this to help with alignment of where our trigger edges are occurring vs missing teeth etc so everything's looking good.
07:49 You do also have the option here to save a trigger pattern.
07:53 This can be useful for diagnostics because you can then send that to Link tech support and they're going to be able to help with diagnosing why you're having triggering issues, So at this stage our trigger inputs are set up correctly.
08:06 Let's just make sure that they are actually working properly while we have our trigger, our fuelling I should say disabled.
08:14 So what we can do here is either press F12, I'll press escape and close that down, or R for run time values and that'll bring up this little box which allows us to sort of dive deep into what's going on inside of the ECU.
08:28 So we've got all of these little tabs across the top here.
08:31 At the moment we're on the fuel tab, and what we want to do is run through here using the right arrow key and I want to be on this triggers and limits screen here.
08:42 So this just allows us to go through a bit of a sanity check, we've already checked with our scope function but we want to also look at our trigger status so this is important here.
08:53 What we're looking for is trigger one signal, at the moment obviously we're not cranking, it's saying no, same with trig two and trig one error counter is showing one.
09:02 The other element to keep in mind with this as well is looking at our engine RPM, during cranking we should be seeing probably somewhere around about 200, 250 RPM, give or take and it should be reasonably consistent.
09:14 So if we're not seeing that, if we're seeing 1000, 1500 RPM during cranking or it's really erratic, it's all over the place and it doesn't match what we're hearing with the engine, these are little red flags for us that we can address here.
09:28 So I'll just highlight this again.
09:30 We're going to crank, what we should see is trig one and trig two signal should turn green.
09:34 We may see our trig one error count increment one or two while I initially start cranking but let's just see what happens.
09:42 OK so that's showing yes and if we look across at our engine speed, you can see it's a little lower than I suggested but we're sitting around 125 to 150 RPM, big element of that would be our battery voltage as well which while I've been talking here has probably gotten down a little bit low in this particular application.
09:59 So essentially that test there, I should have the confidence now and know that we're getting trigger signals that the ECU is accepting and understanding, I've got a sensible engine RPM during cranking, this gives me the confidence that I should be able to get this up and running and basically when it comes time to our initial startup, I don't need to worry too much about whether our trigger settings are correct, with respect of we still do need to set our base ignition timing but again we'll get to that in time.
10:29 Alright let's just go back to our ignition mode, sorry our injection mode, seem to be really struggling getting those confused between injection and ignition but we'll turn our injection mode back to sequential and we'll store that change and we're ready to move on with the next step of our process.

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