- This is our brand
spanking new digital dash. And it's pretty sweet, except for the fact that installing it, meant that we had to
pull out our old gauges, which housed our oil
pressure and our fuel level. And those are kind of important. So today we're gonna install an aftermarket oil pressure sensor and wire it to our standalone ECU. And we're gonna teach the dash to monitor our fuel level again. I don't think it's gonna be very hard, but I've been wrong before. So let's go find out. (upbeat music) Big thank you to car insurance
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seconds of this bizarre, slow motion modernist piece of cinema, while the tagline plays over top. (bright music) - Now, if you've been watching
this show for a while, you may remember when we
replaced our analog gauges, with that DD-EFI digital dash. Now we bought that thing
for about 700 bucks, which isn't very cheap,
but the cool thing about it is that it connects directly to our MegaSquirt standalone ECU, so we can tell our dash
all sorts of engine vitals. And in case you didn't know, engine vitals are kind of important. But that brings us to today. We lost our oil pressure, which
is the ultimate engine vital when we removed our stock gauges. So today we got to get oil pressure back in front of our eyeballs, which means installing
an aftermarket sensor, and wiring it into our MegaSquirt ECU, and then making it come up on the dash. But that's gonna be the
last thing we're gonna do, cause I think it's gonna
take the most time. We're gonna knock out a
few easier things first. We're gonna fix the
refresh rate to get the lag that we're seeing out of there. Then we're gonna get
our GPS Speedo working, and then we're gonna
work on our fuel level. And then once we're done with all that, we will install the oil pressure sensor. And then finally the PAs,
there was this dance, we're gonna put a bezel over the thing, so it doesn't look half done. I can't wait. That's been bugging me for forever. So let's get into it. Now, as far as difficult is concerned, I don't think this is gonna
be that difficult of a job. There is gonna be a fair
amount of work involved, since we're doing a handful of things but, most of it's gonna be easy. I'm sure there's gonna be
some head-scratching involved, with actually getting the ECU
to read the correct values, but I'm positive we can tackle it, although something does
always tend to come up. So we'll see. So first I'm gonna start the car up, so we can look at kind of how
laggy the RPMs are right now. So as I blip the throttle,
take a look at the revs, and you'll see that they kind
of lag, it's a little chunky. (engine revving) You see it's lagging behind. It's not quite in real time. So we need to update that, it's called the lag factor, go figure. And that should look a lot smoother. Let's do that first. All right so to update the lag factor, I'm just gonna go into basic load settings and general settings. So as we go into fixing this, and see how relatively easy it is, you might be wondering
why I didn't do that the first time around. And honestly, it's just, cause
I didn't know what to do. I emailed the owner of the
company that makes this dash and he sent me a whole bunch of info, on how to get all the
little kinks worked out. So that's super helpful, and it's gonna make this way easier than if I
was just poking around, trying to figure it out. So, I think we're gonna
be able to make this happen with little to no drama. Okay, that does seem to be
staying with the RPMs better. Before the TAC was chasing
the actual engine's RPMs. But now with the lag factor bumped up, there's still a touch of a
lag, but it's a lot quicker. I think this is gonna be usable. So that's one thing done. Now let's get the GPS Speedo working. That should be just as easy. - That shows that you did a you probably have to keep
the antenna hooked up. - It's a little obstructed. I mean is plastic, too
much for it to get through? - Possibly. I've run across issues with that actually
happening and everything. A lot of people, even on some of, even on our own test vehicles we do, we put it on the dash so
is still can always point through the windshield
up to the sky itself. So you should be good to go. - Sick. Awesome man. I appreciate it. All right, now that we've got
the Speedo thing figured out, with a little bit of head scratching. It's time to tackle the fuel level. (upbeat music) Oh, Jesus. So the first thing we got to do is find the factory wire that
goes to the fuel level sender in the tank. The thing that tells the
gauge how much fuel we got. So one of these four wires was responsible for sending the fuel
level to the stock gauges. So now I just got to figure out which of the four wires it is. To do that, I'm gonna look at
the stock gauges real quick. (people laughing) Okay. So here we go. So, there are two connectors
on the back of these gauges, and conveniently all of the contacts on these connectors are labeled. All I got to do is look at all the labels and find the one that says fuel. And it is right over yonder. Okay, so fuel goes to pin A on
the driver's side connector. Okay, so now that we see that there, we're gonna go check the connector, that's dangling where these gauges were, and we're gonna check for continuity between pin A and one of the
four wires on that connector. Easy enough to do that and actually check to see which wire connects
back to that sensor, we're gonna have to use our multimeter. So I've got it set to our continuity own testing, diode testing, a notch there. And you cycle through until
the little audio wave shows up. And then any time that these
are effectively connected, you get a beep, like that. So I'm gonna poke around at the connector and at that sensor, till I hear a beep. Pretty easy. Okay so pin A, from the
gauges is for driver's side, so its this guy. we'll just rest our probe in there like so And just so you know, pin A is yellow. One of these four wires is yellow. So I'm gonna guess that that's the one. Okay, see that yellow wire? poke the front. Hey we did it. All right, that's great news. So we're gonna use that wire, ultimately to tell our
ECU how much fuel we have, but it's not quite that easy. So as the fuel level changes, the voltage to this wire changes, and that determines our
fuel level on the gauge. Five volts as reference
to our fuel level sender, and as the fuel level changes, that voltage gets changed as well. And so the voltage as it's changed, we're gonna run that
back in to our connector, through an analog input. And then in the MegaSquirt, we can go in and set up our resistances
and our values for, what the things that
this is sending us mean. So there's a few steps to this, but the first thing we got
to do is get it wired up, and then we'll have to plug in some data into the old computer. So the first thing we're
gonna do is cut back some of the sheathing to
expose our yellow wire. Now we're just gonna measure out the length of our wires roughly. You can always go a little
bit long and trim it later. Now with our wires roughly cut, we can use our vampire clamps, and clip them in to our fuel level wire. Okay, so these vampire
clamps are pretty cool, but they can be a little bit tricky to make sure that
they're in there properly with good connection between the wires you're trying to splice. So it's always a good idea, to go ahead and check
continuity like we did before, just to make sure that
everything's connected. So I'm gonna go into the
terminal at the plug up here, and then I'm gonna make
sure that is connected to the end of my new wire. And since it is, we know that
our connection there is good that that is actually bridging the gap between the two wires. So, spectacular. Always good to check though. Now we'll do the next one check it, and then we're off. (upbeat music) Stupendous. Okay, so now we can go
ahead and put our resistor in line to the reference wire. Resistors are not polarity sensitive, so they can go in either
way doesn't matter. (upbeat music) Alrighty. Now for a
little bit of protection, this is some heat shrink
in assorted colors. (upbeat music) Okay, so not only does that
help protect us from any electrical shocks, but it also helps, strengthen this section where we've just got one little resistor. So that's great. Now that's ready to wire into the ECU. So is this other wire. So now I just need to
stick the correct jumpers, out of my option plug
on the back of the ECU. I'm gonna go ahead and put
a little bit of sheathing over the pair of these wires, protect them a little more
and cause it looks nice. (upbeat music) Okay, so we've got our
options port down here, and I'm on the internet, and I've got the diagram
of what these pins are. So I'm looking for our
five volt reference, and that's gonna be the wire
that has the resistor in it. And then I'm looking for
analog input one or two, I think I've got number two already used. So we can see that five
volt references is pin H yonder and analog one or two is C and D. So I'll use one of those. So let's get the five
volt reference done first, plug that into H and connect it to the one that I know as the resistor. So our fuel level sensor,
like many and most sensors, is basically just a variable resistor. Depending on how much fuel is in the tank, that'll put the fuel level sensor at a different level and will
create a different resistance, for like an oil pressure sensor. Depending on how much pressure is being pushed on the sensor, we'll determine how much
resistance that sensor gives off. So basically all we're doing here is sending a five volt
reference to the sensor, and basically it puts a
resistance into that circuit, and then we measure how
much resistance there is, and then we correlate that to a fuel level or to an oil pressure. So since we've done the wiring, now all we've got to do
is go into the computer and plug in those resistances
to tell the computer what to correlate, an empty fuel tank to, and a full fuel tank and
then everything in between. So we're basically
gonna go in the computer and mimic the stock fuel level setup with our wiring here. We've got our values ready. So, first I ran come up
into the MegaSquirt software advanced engine, we're gonna go to the
generic sensor inputs. So I'm gonna go ahead
and use analog in one as our source for the sensor. That's where we have the fuel
level sensor running back into the ECU. So analog in one, we will also name it fuel
zero volt is negative 11 negative 11, and five volts is 380. That should be all the doing
we need to do in there. Now on my gauges here, I'm
gonna set this guy right here up to be my fuel level gauge, right click. And we're gonna go up here, to our generic sensor inputs
and hit fuel level baby. And then look at that. Okay, now that we got our
fuel level sensor handled, it's time to work on
our oil pressure sensor. So our oil pressure
sensor is very similar, to our fuel level sensor, in that it's a five volt sensor. It's resistance changes with
changes in oil pressure, and we correlate that to
actual oil pressure numbers on the dash. It's gonna be similar in wiring. We just got to wire up that away. So first I'm gonna put
two wires in the car from the ECU area up to the front through the firewall and into
the oil pressure sensor area. (upbeat music) Okay, so wires are run
through the firewall. That was pretty easy. now for the part that I'm
concerned might be a little tricky which is getting to the
oil pressure sensor area. So we'll see if I can get to it. It may be difficult. All right, there's no easy path to this thing from the top or the bottom. So I'm gonna have to take,
get some stuff out of the way. I'm hoping that if I
take off the oil filter, and the sandwich plate that
runs through the oil cooler that that'll give me enough access to get to this puppy from down here. Oil everywhere, not as bad
as the coolant recently. (upbeat music) Okay, there's that guy
and then direct the oil. Ah, okay. Oh, now I can see it. I think we might just be able to do it. (upbeat music) No problem. Okay, so this is obviously a
lot smaller than the old one. This is an NPT thread, which is different than the thread that's in
the block of the Miata. They are different by one thread per inch, not much but enough to matter
and know enough to leak. So I have an adapter to
be our little go between, and that's cool. The threads are also
responsible for sealing, whatever you're measuring. So for us that's oil. So on taper thread, you're gonna wanna add thread sealant. Then we'll jam this thing in, then we've got this pigtail. And what we got going on here. One of these things is gonna
be a ground to the chassis. One is gonna go to our
analog port on the ECU just like the fuel level sensor did, and the other is gonna go
to our five volt reference on the ECU, just like our fuel sensor did. And then we'll basically
have to do the same stuff in the ECU that we had to do to get our fuel level sensor working. So, you know, all these five
volt sensors kind of similar. (upbeat music) Now it's important when you're soldering to just heat up the joint. Heat up the wires that you're
trying to solder together, and poke the solder just into the wires. And once the wires are hot
enough from the soldering gun, the wires themselves will melt the solder. If the solder doesn't get hot enough, it'll be even more brittle than if it was correctly up to temp. So always heat up your joint and then plow the solder
just into the joint, down the line a little bit. (upbeat music) Alright, let's get that
heat shrink in place. Okay, so our soldering is done. Our harness is on. Now. We just need to find
somewhere to ground this guy. Then we can pull the rest of
our wire through the firewall. Luckily, this is gonna be pretty easy cause I was doing a little
bit of thinking ahead, and I already a spliced
us a five volt reference off of the one we use for the fuel level. So all I gotta do is hook up
our five volt reference wire to the five volt. Red wire is going to be
our analog signal back in to the old standalone. (upbeat music) All right. So there we have it. The wiring is done. For now let's hop into the ECU and see if we can get
this puppy sensoring. Actually just on the
Amazon page for the sensor. So basically this gives us
everything that we need. It tells you the wiring pin
out, which is what I used to wire the thing up. And then it also gives
you the output voltage for different PSIs. So 0.5 volts, zero PSI,
50 PSI is 2.5 volts. 100 PSI is 4.5 volts. So I basically just need
to input those data points into the ECU like we did
with the fuel level sensor. Analog in one oil
pressure, linear sensors, zero to a hundred, burnt. All right, so let's fire this thing up and see if we have any oil pressure. (engine revving) And so with that, we have made
this car a lot more useful. I can tell how much fuel in the tank. I can tell how much oil
pressures in the engine. I can tell how fast I'm going. So here's just one thing left to do. Just take a look at this dash like this. (upbeat music) Wow, that looks pretty good. It actually looks complete
and I'm happy about it. And it actually is useful with
a lot of useful information. So the Miata just got a
lot better in my opinion. I'm very excited about this. So thanks again for watching. I hope you guys liked it and
I hope you learned something. This episode was maybe a little bit more in the weeds than normal. You know, I'm doing some
pretty in-depth stuff, so I hope you liked it. Let us know if you did. And if you did like the video. And go follow me on Instagram and follow donut media while you're there. See you guys next Wednesday.
