N62 Z3 Part 4: More Wiring & Fuses

Okay, so I have gone from thinking I will need to change under 15 pins to having now changed over 45... earlier at the shop I laid out the fuseholder, fuseblock, IVM and distribution block I am adding to the car and after I stepped back for a minute I was kind of just like... what the hell am I doing? How did I even get here? Is this even going to be possible?


But let us take a step back first... today was a long day at the shop - and all working on the swap. It didn't feel like a lot was done looking back on it (or at the pictures) - the work I am doing now is kind of tedious - sludgy was the word that kept coming to mind earlier. Just got to get through it though... it was definitely a lot more exciting when there were big changes happening every day, you know - engines coming out, engines going in


We will go back to the start of the day... the first thing I did was raise the engine to it's proper height. Finally - we can see the hookup location for the steering shaft! I will be able to do more work to see if that fits, or what needs to be done to make it fit, once the subframe is notched and in position

I do think I may need to be a little careful with O2 sensor placement as these are wideband O2's and that may make them a little more sensitive to specific placement than regular O2's... hmm...


I also bolted in the passenger side header fully and clearance looks great on that side - as well as the driver's side, even with the engine a tad higher up. The fuel lines look like they will be running pretty close to the exhaust on the driver's side. Some of that fuel system stuff has a heat shield but for the single line running to the engine I will bend a custom line and move it further from the exhaust. A custom line was required anyways, to place the fuel outlet at the correct location for the N62

I also started to investigate the driveshaft alignment a bit. I have no reason to think it's not straight but sure looks a bit off center... kind of interesting. And as you may see - fitment is very tight. The insulation foam will need to be trimmed around the linkage

These are some of the areas that are going to be cut out... ouch!

I believe on the passenger side of the motor here the above image is of the timing chain tensioner bolt. It does not hit the frame rail at the correct height (as pictured), but when the engine droops it rubs very slightly. I plan on using OE E36/Z3 engine mounts and I am building this car as OE as possible, as I intend to keep it and enjoy it for a long time. This means the engine mounts may eventually sag as they do when they wear out so any areas that interfere must be clearanced. Hack it out, reinforce it, spray some rust proofing from behind, boom


You may also notice in the above image the A/C line is just about in place. I couldn't help myself - I just had to know if it was going to fit. It totally will. It may need a little massaging but come on - it's already there!


At this point I took a little time looking around my shop for a few things I need. Manual E36 pedals and an E36 manual clutch line... although I don't know if the clutch line will work for me... I will probably bend a custom line anyways. I also had some brand new engine and transmission mounts. I was about to order some online but thought I had some and sure enough I did. It will be important to ensure they are both new so when I align the engine to build the engine mounts, I am building everything "straight" based on new, proper height stuff

Then I was thinking about going to the junkyard for some things I needed. But looked around my shop first and found this in a parts car. As far as I am aware this is called a power distribution block. I needed it mostly for the 100amp fuse and the 50amp fuse

At this point I realized I have a lot of... stuff... that I want to fit in the DME box. So I cleared it out, verified the routing of all the wires was good then test fit the bits I wanted in there, modified it here and there with my handy dandy dremel and got test fitting, cut again, etc... After much consideration, I have discerned that I simply do not have room in the fusebox for the power distribution block. It was either that or the IVM and I think the IVM is more sensitive. The other compartments are being taken up by the fuseholders I have to add, the Valvetronic DME and the engine DME. I could probably fit it all if I took out the organizer shelf piece but I don't really like that idea personally. At least for now - the plan is to mount the distribution block just on the outside of the DME box. I mocked it up in a pretty good place. It is held in place with a single M6 bolt on the car I took it from. I will use my riv-nut tool to set an M6 rivnut in place when I finalize it's position. But I haven't finalized it yet. Boo. I wanted to riv-nut something

Another thing I have to do, at least something I think I have to do, was find the starter wire line from the EWS. It goes into to the IVM, instead of going directly into the engine harness like on the M52TU. I thought I would use this mode to indicate visually the continuity... I guess in hindsight my little light tester would have worked too

So I had located a 100amp and 50amp fuse holder with the distribution block, but I needed a smaller fuseholder too, for four 5-10amp fuses. Found this in the trunk... nice

I separated the fuseblocks (the black pieces within the fuse holder panel) and I don't remember why now but neither of those fuseblocks worked for me - I ended up scavenging the same style fuseblock, with better fuse allotment, off a different parts car. However I did keep the separate large fuse holder on the bottom of the fuse holder panel in the above image. I noticed a plethora of these large style fuses in yet another parts car (that I was searching earlier for various harnesses/whatnots) and scavenged it for all the large fuses in various amperages in the above image (20a-60a). This ended up being perfect, as I have one wire where I know it goes to constant power but I am unsure of the exact amperage it needs. The diagram is a little unclear, some models seem to indicate 30a, some 50a. I will run a lower amp fuse (maybe even starting with the 20a) and leave this fuse in an area easily accessible once the DME lid is off


Then I started laying out the wiring. It doesn't look like much. But it makes sense in my head and it's nice to see things start to come together a bit

Let's talk about that one power line going straight to the power rail on the distribution block. I was considering doing this because it runs to that large fuse I was just talking about and as it is a fused source already, I didn't see the need to add a second fuse. However, I have spare 80a fuses that fit this distribution block and now I am learning towards adding those in for a second layer of protection


Anyways, once mocked up , I had to start visualizing where it was going to go in it's final position. It may seem a little presumptuous to do this "beautification" step now but my goal is to eventually make everything look as neat as possible and it is way easier to just spend a little extra time doing it now

This, by the way, was my "What the hell am I doing?" moment


There is one more plug that plugs into the IVM from below - essentially the IVM's body harness - so I am making sure to route all the wires in the correct orientation with this in mind. This is one of the main things I was checking earlier when I cleaned everything up and checked the routing


That pretty much wraps up the wiring. I am waiting on DME pins and I found some other pins I needed too and ordered those as well. Once those arrive I can finish the wiring... everything should be finalized as far as where stuff goes, just need to find a switched power source in the DME box. I did not fully realize how much I had not done when I finished last time. I had only just begun... but I am very close to being done now!


I've also been spending a lot of time just moving around the car. Up and down, around - and I keep having this crazy intense fear of poking my eye out on one of those framerail studs. I mean that wasn't the only reason I did it but four were already hammered out so I figured why not finish the job. So I cut the driver's side ones out, they were welded in from the back so I had to cut them free before they could be hammered out. Then I riv-nutted in some M6 riv-nuts

Yay riv-nuts. So now instead of nuts over a stud holding my bumper support bar on, it uses bolts... not a big difference at all. Makes installation marginally harder if anything because you can't "hang" the bumper on the studs. I may thread one stud into one on each side before final installation for that reason


Then I went home, ate dinner, realized I forgot to pay rent at the shop and it's due before tomorrow, went and paid it at their late night drop-off and decided hey why not stop by the shop and test the last few wires I need? I was looking for a switched 12v source for the fusebox with the smaller fuses. I found 2 - just the number I needed - and some constants too. I may use those constant supply the two smaller fusebox fuses instead of the distribution block. Still deciding on that. I'm also deciding how I want to run the main power wire for the distribution block but I have a few options... but with that, the wiring routing should be completely done!

Sure looks good... hope it all works out. It's still a bit of a shot in the dark to be honest. I think it should. I'm optimistic!


If you enjoyed Part 4, just wait until you see Part 5!

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