So I did a V8 swap

[Everett AL]

So I did a V8 swap a while back and the Ex has been up and down since. She's not my daily so she's gotten neglected and forgotten about for long periods of time. Let me start this by saying this was done in a garage with a buddy. This thing has no business cranking or being around. This is very much a project, I'm learning as I go and I'm on my own working on it now. So go easy on me, there is some wiring from speakers and stuff left over from when I was in high school almost 15 years ago.



I am going to try and summarize what we are working with, unfortunately with how long ago everything was I am having a hard time remembering specifics.

My Ex is a 2001 Explorer XLT 4.0L SOHC

Donor Engine and Trans were ordered I believe I got either a 2000 or a 2001 5L out of a mountaineer? (Not 100% sure)



I got most of the engine installed but started to have issues finding bolts, we didn't do a good enough job keeping track of bolts and where they went when we tore the engine down to stud the heads and re-gasket everything. So I ended up finding a donor 5L explorer, 1999 I think which I mostly pulled bolts from, and then luckily we had that truck I took the pats system out of it. I don't remember swapping the GEM but we may have? I just remember figuring out the PATs system and cranking it for the first time. Such a relief!
Here is a picture of my GEM I took the other day.

Then minor issues here and there leading us to this week. I figured out my Battery Saver Relay was bad and now she doesn't kill the battery overnight. fixing that and driving her to work for the first time in like 3 years has motivated me to start finishing up some of the other little issues here and there. Right now my 2 current issues are below:



Issue 1, is my oil pressure gauge. it reads zero. It would be nice if it worked but I'd be happy if it just read something so my check gauge light would go off. I like a clean cluster, no lights. I think the picture below is the body to engine harness. I worried about cutting wires on the harness without someone cosigning it for me. I haven't had a chance to get in there and try to jump the switch to see if it reads right at the gauge. After looking over the V8 for dummies how to, and speaking with Fortune410, I don't think it'll work anyways because I don't remember doing much with the engine and body wire harnesses when we did the swap.

The picture below is what I think is the connectors that the thread was talking about needing to rewire. It is between the battery and the relay box on the driver side. For context the bottom of the photo is the battery.

Do we think we can connect a couple wires and get the guage to work or is it simpler to cut a wire and ground it?

Issue 2, is my AC compressor won't kick on. This is due in part to not having a high pressure switch installed. lol. a buddy installed an override switch so I can manually turn the compressor on and I'll get ice cold AC. We were worried about too much pressure building since it's on a switch. I took a picture of where I think the switch is supposed to be installed. I'll have to get a pigtail to pull a part of something. If it's something I can even fix.

Hopefully this is enough info for you guys to start with. It is getting late and I've got work in the morning. Thank you all for your help in advance. Please dumb down any advice you have. I'm not offended if you break it down Barney style for me. I probably need it that way anyways. I have no idea how I've made it this far with this truck.

 

[410Fortune]

Excellent work!! She’s your old high school truck eh? Sick!!

So 01 sohc converted to 99 5.0
You install the key tumbler pats
Module and pcm from the 5.0

Now you need to do a little wiring
It’s not much
Just a little

You can keep your 01 gem module there is no real need to swap to a 5.0 gem

Is this truck rwd or awd?

Yes that is the plug where much of the wiring will be taking place

I’m gonna get some wiring info together for you

The good news is there are literally no changes between a 99 and 01 truck as far as the drivetrain is concerned
The changes you will be making are v6 vs v8 as they come off the assembly
Line. The v8 simply routed a few wires differently

 

[Everett AL]

My truck (V6) was a 4x4 model and the V8 was an AWD. I forgot to put that I did the BW4406 swap as well. I followed this and couple other how to threads.

How to: - Convert V8 AWD to BW 4406 Manual Shift- A how to thread

Convert 1996-2001 V8 AWD to Manual Shift BW4406 EDIT: There is a write up on how to connect the indicator lights a few posts down, near the bottom of the page. AWD is a great method for putting power to all four wheels, but it does it somewhat inefficiently and doesn’t offer low range. A...

www.explorerforum.com

 

[410Fortune]

Is your 4406
Manual shift or electric? If it’s electric then you must keep your v6 gem module as it is the 4wd shift motor controller

 

[Everett AL]

It's stick. And I wired the shift lights into the dash lights. I didn't do the relay version. So 4hi is the 4x4 light and 4lo is both lights. Which I'm fine with.

 

[Everett AL]

Hey I'm going to try and go to a local junkyard tomorrow to get the pigtail and probably the switch as well. Does it matter the explorer I get it from? Is V6/V8 high pressure switches different?

Also decided to risk it for the biscuit yesterday and take it on a trail I found not to far away. She didn't do too bad.

 

[410Fortune]

All these trucks use same connectors for high and low pressure switches

Here is the wiring connector in question
C125

And ac / heater wring

You should also have the engine controls wiring for the oil pressure switch and others

 

[410Fortune]

Instrument cluster for oil pressure switch

 

[410Fortune]

These books super handy can find on eBay under $30 usually
To say mine is well used would be an understatement
This book alone has made it possible to convert 10+ trucks to v8 over the years
I’m have many many of these books for explorers and rangers

Money well spent

 

[Everett AL]

so looking at 54-3 the AC Pressure cutoff switch is the "high pressure" switch by the battery. I got a switch and wire harness from pullapart today. The Black/white wire goes to a ground, (i assume it doesn't matter where just grounded?

The Red/yellow wire is what confuses me. what do I connect that to? Looks like I need to cut the Red yellow wire on the engine side of the connector the one leading away from the fender and connect the Red/yellow from the sensor to that? so it connects through the connector.

I ordered the book on eBay. thank you.

And I'm curious if I understand this correctly the switches are on/off depending on the pressures they experience. and when they are closed(connected) they allow the circuit to ground which will power the AC clutch to kick on? maybe over simplified but am I on the right track here?

 

[Everett AL]

So the Female side doesn't have the red yellow wire and it is on the engine side of the connectors. the male side has it and it from 4.0.

couldn't I just cut the red yellow wire from the engine bay side (male side) and run it straight to the high pressure switch? just bypass the whole connector?

looks like there are a lot of wires that aren't lined up right between the connectors.

 

[410Fortune]

The red yellow comes from the low pressure switch which is on the other side of the engine bay it comes over through the c115 connector which is the large 42 pin square plug

Many of your assumptions are correct this far… remember the v6 and v8 wire some things differently which is why your plugs don’t match up

More later….

 

[Everett AL]

Ok so yea I think I should be able to cut this red yellow wire at the c125 connector body/bay side and connect it straight to the high pressure switch. No need to go though the c125 connector at all. And then ground the other wire on pigtail

 

[410Fortune]

It should go through the low pressure switch as well as the high pressure

Look at the ac diagrams I posted earlier and try to mimic it, most of the wiring is there from your old v6 you just need to move some pins

 

[Everett AL]

alright so i think i got both solved. the AC is the one I don't know yet it is cold here so it's hard to tell if the compressor has kicked on or not.

Looking at the diagram I went low side (passenger side by the dryer) to the high side by the battery. they are connected via the red/yellow wire. I had continuity between them.

so provided I have enough refrigerant and the switches aren't bad that should work for the AC

and for the pressure light, I took cut the green/white wire from the female side of the c115 connector and ran it to the C125 connector female side and connected it so the signal goes through C125 into the male sided and onward from there.

the Red connection is what I made. and it works.

Thanks a ton for the help and the recommendation on the wiring diagram I think I am starting to understand how to read it. Can't wait for mine to arrive.

 

[410Fortune]

Well done

You are welcome!