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Megasquirting my WD21


Adam
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IMG_20120612_190337-1.jpg

 

Here's where it sits now. I'll be building a cable for the sequential injection part of this as well. If anyone knows the answer to my coolant sensor question let me know... I've looked through the FSM but can't find the answer... If need be I'll pull out my multimeter and check it myself...

 

Oh, and if anyone knows which wire on the plug goes to the outer ring optical sensor for the crank sensor... I don't need the inner one.

Edited by Adam
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Another tip for the case, you can get things called "project boxes" at electronic stores that are made for this kinda thing. I have to pic them up for work all the time, they aren't too expensive and come in many shapes/sizes.

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Figured out the coolant temp sensor, one side definitely excites it and it reads off the other side. The green/red strip wire is the one responsible for supplying power. I'll be looking at the harness to figure out which one specifically it is tomorrow. Tonight I'll be making a chart for the coolant temp sensor resistance all the way from room temp to boiling.

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Coolant temp sensor readings are as follows:

 

75F 2000ohm

85F 1750ohm

95F 1400ohm

105F 1300ohm

115F 1200ohm

125F 1000ohm

135F 800ohm

145F 700ohm

155F 600ohm

165F 500ohm

175F 450ohm

185F 400ohm

195F 350ohm

205F 250ohm

210F 200ohm

 

The water stopped gaining temperature right around 210 no matter how much salt I added but 210 is just fine.

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One other note for anyone in the future who may go the Megasquirt route, there isn't an input for the knock sensor on either the MS3 or MS3X harness. You can use a spare input on the cable or you can use an input on the MS3 board. I chose a spare input on the MS3 board, I'll be using the JS4 input, it's directly under the CPU socket and you just solder a wire directly to it underneath the board.

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IMG_20120613_134437-1.jpg

Got my coils, wideband and crank sensor replacement plate (under the wideband, oops) :lmao: It's like Christmas :lol: I'm going to try to get it to start tonight, if I do I'll immediately do some datalogging and try to get a decent tune with VE Analyzer.

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IMG_20120613_164457.jpg

 

I've been able to mount the brackets to existing bolt holes with little to no modification :D I had to drill out a single hole on the brackets so I could run a bolt through it instead of threading the bolt into it but otherwise it all lined up quite nicely. This will enable me to run LSx wires so ignore the crappy wire routing :lol:

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Been working on the wiring harness for the coils. So far I've soldered all the ground wires, then I hooked the wires up, routed them where I wanted them to go and electrical taped them in place. Now I can build the hot wire and the trigger wire into the same shape and tape it all up without having to stand over the Pathfinder the whole time.

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Didn't manage to finish it today but I'm very close. Got all the wiring to the cab, need to wire up the coils and the O2 sensor. The coils are one of the easiest things. Still need to read up on how the O2 sensor is wired.

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dude, i gotta say mad props to you for this thread. awesome info and awesome pics/details. I am about to start tuning my pathy to make use of the bigger engine and breather mods/cams, and soon to be turbo. great job man, keep it comin'!

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I'll have some more info tomorrow on how I mounted the LSx coils. I'll also have some other minor info on the wiring and other such things. Can't really update that stuff right now because it's dark and everything is out in the Pathfinder!

 

And thanks, I like to share my knowledge no matter what I'm doing. Don't see the point in living in a bubble if I can help others!

Edited by Adam
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I just browsed through this thread for the first time.

 

Good work! I've never seen a mega squirt going onto a Pathfinder before! I really need to practice my soldering now! :laugh:

 

I'm curious to see how the individual coils work out for you too!

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Having troubles already, it doesn't pick up the TPS and I'm not sure I'm using the correct crank sensor. About to check the logs. I also didn't realize the stock wires don't even make a connection to the coils, I had to grab a set of my BMW wires I had sitting around, which also means I had to take the caps off the plugs so they could attach to the threading.

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I figured out the throttle position sensor. Red wire on the TPS is 12v, black wire is ground and the white wire is the signal. It works beautifully now.

 

Still can't get the crank sensor going. I've tried 2 different methods to pipe it through on the Megasquirt and it's just not working. One method involves treating it like a VR sensor but providing 12v power to it, the other is the actual optical sensor circuitry that comes with the Megasquirt. In both cases it's just not working... I'm not sure if maybe I have it just hooked to the wrong input or what but even then, I can't get it to register a voltage drop with my multimeter when the optical sensors are closed off by the plate...

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Well, I can't even get an RPM signal with the JimStim, which is made to send a signal like that... Not good, gonna have to figure out where I went wrong with my crank sensor circuit...

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Just confirmed it's not the CAS, I'm getting a jump in the multimeter when I check voltage across the 12v pin and the trigger pins, meaning the sensor is working properly. Definitely an issue on my Megasquirt...

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OMG I got it!

 

I'll explain the TPS wiring and the crank sensor tomorrow when I figure out exactly which wires are going to be wired to which plugs.

Edited by Adam
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Well, I know all the sensors I hooked up are working, everything is showing up on the screen. The exhaust reeks of fuel so I know the injectors are firing, unfortunately I'm not getting any spark. I've checked everything and it seems that the Megasquirt isn't even sending the fire command over the signal wires... Reached out to the MS3 forums for help.

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I think I've figured it out on my own, I just realized I need to hook up the secondary trigger from the crank sensor wheel...

 

Nope, still no spark...

Edited by Adam
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Dude, you rock.

You mentioned being low on funds... You should get the kinks out of the megasquirt and document the improvements. Then start making them in your spare time and selling them for some extra spending cash.

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May have wired the coils backwards, I'm not 100% yet but I've seen mention that they're wired like LS2 coils, which are wired opposite of LS1 coils... I assumed they were wired like LS1 coils so I'll probably have to rewire...

 

Related, here's the ignition wiring harness.

 

IMG_20120615_221819-1.jpg

 

Red wires on the bottom of the image are the +12v wires, green wires (and one brown) are the ground wires and the colored wires in the loop are the signal wires for the individual ignition coil triggers. The wires wrap around the top of the engine and look pretty clean when everything is connected up...

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