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Megasquirting my WD21


Adam
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240sx KA24DE throttle body is also 60MM and bolts right on (minus boring the manifold) and the TPS isn't upside down either. Put one on mine a few weeks ago, made it pretty snappy.

Yeah I looked at those as well but they were generally more expensive :/

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We had a couple in my local Pick N Pull last time out. I'm going out today so I'll check again. Sounds like a fun project!

 

Awesome, if you find one shoot me a pm.

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240sx KA24DE throttle body is also 60MM and bolts right on (minus boring the manifold) and the TPS isn't upside down either. Put one on mine a few weeks ago, made it pretty snappy.

I forgot to mention that part, but the Pathfinder manifold opens up really quick after the TB so you can actually open it up to 60 really quickly with a dremel using a 60mm gasket as your guide. MUCH easier than the other style manifolds.

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Hmmm, not sure I'm catching your drift with that or what you're comparing to? Porting the Z31 manifold to fit the throttle body took like 10 minutes. The upper part lined almost exactly up, it's the bottom and some of the sides that need about 1/8" taken off.

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It will be MAP (Manifold Absolute Pressure) sensor based, it's a much better system than a MAF.

 

It's not a better system but a cheaper system to implement because the ECU relies on air/fuel look up instead of a direct reading from the sensor. It is a much easier system to tune unless you are dealing with a stock ECU that uses MAP technology. The MAF style system is superior to a MAP based system because the drive-ability with a MAF is much smoother and you get a better torque curve however you can hurt the top end power because of the obvious flow restriction that MAF sensors can have.

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however you can hurt the top end power because of the obvious flow restriction that MAF sensors can have.

 

Hence why I feel MAP is superior :jig:

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It all depends on the usage scenario I guess. MAF responds better to small modifications without needing a tune again while MAP seems to be more reliable and easier to deal with as long as nothing is changed.

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It all depends on the usage scenario I guess. MAF responds better to small modifications without needing a tune again while MAP seems to be more reliable and easier to deal with as long as nothing is changed.

 

Not really a concern with the Megasquirt and VE Analyzer...

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Hmmm, not sure I'm catching your drift with that or what you're comparing to? Porting the Z31 manifold to fit the throttle body took like 10 minutes. The upper part lined almost exactly up, it's the bottom and some of the sides that need about 1/8" taken off.

My Mistake, I though the whole neck had to be opened up on the z31 manifold.

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LOL

20 miles and an hour or more drive.....Nevada, Tx is right next to BFE, Tx....

I need to go there anyways, there's an AC compressor at that boneyard :laugh:

 

IMG_20120611_152515-1.jpg

 

Replaced the DB connectors with pins that I can solder wires directly to easily and shrink wrap for added support.

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Didn't check the mail until just now, got me spare ECU in!!!

 

IMG_20120611_211014.jpg

 

It's gonna be a tight fit, if it even fits. I may have to open it up on each side and make cover plates.

 

IMG_20120611_211042.jpg

 

This is the orientation I'd like to put the Megasquirt in inside the case. We'll see how possible this is to achieve.

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Well, initial findings aren't great. The USB port makes the MS3X board too tall to fit in the short casing of the Pathfinder ECU. Still considering options.

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Been hacking away at the stock ECU housing getting things situated. Here's where I'm at:

 

IMG_20120611_231357-1.jpg

 

You can see I've moved the MAP sensor to the side of the ECU housing, the barb for it will stick out the top of the ECU, it wasn't in a very good place under the board (stock location for the MS3X if you use the case supplied by DIYAutoTune).

 

I'm not 100% sure how I'm going to approach the back half of the case so it's not just wide open... Jury is still out on that.

 

 

Here it is with the cover on, you can see the MAP sensor hanging out:

 

IMG_20120611_233417.jpg

Edited by Adam
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i have a few times made cases for my own electronics. if you had access to a small break or even if you are handy with some sheet metal benders you could quite easilly make a cap with some mounting tabs with holes drilled in them out of sheet metal. drill a couple holes on the flat surface near the edge of the hole you cut in the stock ecu casing and tap them for some uber small computer screws. i can envision it right now.

Edited by Nefarious
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i have a few times made cases for my own electronics. if you had access to a small break or even if you are handy with some sheet metal benders you could quite easilly make a cap with some mounting tabs with holes drilled in them out of sheet metal. drill a couple holes on the flat surface near the edge of the hole you cut in the stock ecu casing and tap them for some uber small computer screws. i can envision it right now.

 

That's definitely something I'm considering.

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Mounted the MS3X in the Pathfinder ECU at its final location:

 

IMG_20120612_141634.jpg

The 3 red squiggles are the 3 mount points, the board is suspended above the sheet metal bottom by a screw and a nut.

 

IMG_20120612_142646.jpg

Here's everything completely mounted, all add-on boards. Time to start the wiring!

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PathfinderWiringDiagram.png

Put the ECU pinout diagram and the wiring to pin diagram on a single image file for quick reference... Don't like how the FSM has it (especially since I have the FSM in PDF format)...

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Wired the injectors:

 

IMG_20120612_160612.jpg

 

The Pathfinder's firing order is 1-2-3-4-5-6 so this part is simple. On the Megasquirt you wire the injectors in the order they fire, since they fire sequentially you wire A to 1, B to 2, etc etc... The Megasquirt information tells you all this but it helps to have it all in the thread.

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So looking at the diagram I've got some questions.

 

The coolant temperature sensor has 2 outputs on the Pathfinder ECU, what gives? Is one a 12V source and the other the one that actually reads the resistance?

 

Is pin 19 to the O2 sensor the O2 sensor heater circuit? I'd assume so based on the drawing.

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