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Discussion Starter #1
Hey guy,

I have made it a long way. Im ready to wire the car and fire it!

I bought a harness out of a 95 5.0, but I can't for the life of me figure out where half the connectors go, and why the hell you need so many wires. Looking at the massive harness, I would prefer to make my own and not clutter up the engine bay with crap I don't need.

I am damn good with wiring, as a build all my own harnesses form scratch on the motorcycles I build...but thats also with a complete wiring diagram.

My first question is referring to the MAF.

As seen in the pic below, there are only 3 wires at the MAF connector...yet my MAF has 6 wires (with a 4 wire adapter by the looks) coming out of it. And ALL of the MAF pigtails I am able to buy have more than 3 wires. So how the heck do I know which wires go where? This is the one that really has me stumped. Any help here would be AWESOME.



Second question is for the second pic. I know the 95 uses a CCRM (also not shown in the wiring diagram), but if I only want the fuel pump, and PCM power function relay from this (no fans, A/C) can I just simply run wires to power these with individual standard relays? Im 99.99% sure this is fine, I just want to make sure there isn't something crazy that it does that i'm missing.





The wiring diagram I am referencing.

 

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Discussion Starter #2
Typical. I do 100 hours of research and find nothing, then I found this...

Is this my answer?



 

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If you have 6 wires going to your MAF connector then chances are they were running a slot style MAF and those have the IAT built into them so the extra 2 wires may be for that.
 

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if you omit wires

you will get cel

a lot of circuits are monitored
 

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Be real careful following schematics!!

All properly designed high resolution wide dynamic range or noise-critical circuits isolate power grounds that carry any significant current from signal grounds. They have to be wired in a particular fashion that may be different than it appears on a simple schematic.

A power ground and signal ground can be common at one point, but not at two points. Because of that, the common point connected wires might appear as a single wire in areas where they are really still two wires.

I hope this is understandable. I can give you a specific example in the 1989 Mustang negative battery connection. The negative post routing is heavy cable from battery terminal to the block, and a smaller wire from the battery terminal connector to the vehicle chassis. The smaller terminal wire is common at the ground lug with the injector and other very noisy grounds. The routing is critical for safety and noise mitigation, but it does not appear in the Ford OEM schematics exactly like wires really connect in the actual car. Look at what the Ford OEM schematic shows below for negative post. It is nothing like the actual battery negative wiring!!
 

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I concur with TomR,

if you need to wire the car, use actual wiring diagrams for the car, not some made up ones on the internet

real diagram, cost real money
 

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Discussion Starter #8
...use actual wiring diagrams for the car, not some made up ones on the internet
Agreed. I'll try and pick one of these up to reference. Does anyone know where I can pickup a good diagram?

All properly designed high resolution wide dynamic range or noise-critical circuits isolate power grounds that carry any significant current from signal grounds.

...The smaller terminal wire is common at the ground lug with the injector and other very noisy grounds. The routing is critical for safety and noise mitigation, but it does not appear in the Ford OEM schematics exactly like wires really connect in the actual car...
Grounding loops. When wiring I make sure that any and all grounded sensors/sensitive instruments meet at one common point. This drastically helps eliminate the noise. I don't plan on tagging grounds all over the chassis.

Next question:

My blow thru Pro-M Meter has a 6 pin hub on it. There is a 4 pin connector plugged into it to attach to the stock harness. I have read the 6 pin connection is to utilize an IAT function on the MAF. Can I use these outer 2 pins for my IAT sensor rather than a separate sensor? The reason I ask is I will need to weld in another bung for the IAT sensor. But if I can just use the MAF's function to do so, I would rather go that route.
 

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helm publications evtm
all data
bbb industries
Mitchell on demand

you can use the iat in the maf housing, but you need to make sure the parameters associated with its placement in that location is correct

ie, if your tune is setup for it to be in the intake, vs the maf

obviously you can see there will be a temp difference.
 

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Discussion Starter #10
Update: Slowly chipping away at getting all my connectors trimmed and cleaned up for the re-wire.

My most recent puzzle is my distributor connector / TFI interface.

So my distributor has the 7 pin circular like connector. I found some diagrams that detail how the 7 pin connects with the TFI, grounds, starting circuit and the ECM module itself.

First; With my 7 pin from the harness trimmed and de-loomed, pins 2 and 6 are spliced together. This can be seen in the first picture below. Perfect.

Next; You can see that in that same diagram, pins 4 and 8 are shown as being connected. I have seen this same depiction in other diagrams as well. However the un-loomed connector reveals that these two wires are NOT spliced together. When referencing the picture you can see that for the 7 pin connector, there is a "PIP B" that runs between the dizzy and the TFI module, and a "PIP A" that runs between the dizzy and the ECM.

Does anyone know which pin number on the dizzy should reference "PIP A" or "PIP B" in the second diagram?



 
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