Another F81 Build Thread

[Matt@Evolve]

An incredible milestone! Congrats.

[Gunzy]

Not many comments as most are just observing but amazing build man.

[GOTUBCH]

This is amazing!! and you are making quick work of it...

[jaylazy2020]

Incredible progress. This would be a huge hit on YouTube not just because it’s F81 but the progress is so fast.

[TheHunterHofman]

Truly amazing work this! Love the F8X platform; this is seeing a dream unfold!

[e46IX]

Wow you work fast, and your workmanship looks fantastic too. Great stuff.

Originally Posted by attbimmer

So now the options were, take the engine back out a bit and get the driveshaft aligned while installing the engine (didn't want to do that), loosen the unholy nut of doom on the diff side of the drive shaft, or drop the rear subframe again. I ended up doing the latter. Was a bit of a bummer since that meant I had to undo the brake lines again, disconnect all the electrical and unbolt. Overall though it was much easier then the other options.

Just wanted to touch on this paragraph here, curious why you wouldn't just undo the reverse threaded nut that connects to the diff? Is it because you're worried that it will vibrate after or just a pain in the ass to break the nut loose? Cause to me it seems like way less work to just undo the driveshaft compared to dropping and re-installing the whole rear end again.

[G80Jeff]

This is absolutely incredible sir. Amazing work!!

[attbimmer]

Originally Posted by e46IX

Wow you work fast, and your workmanship looks fantastic too. Great stuff.



Just wanted to touch on this paragraph here, curious why you wouldn't just undo the reverse threaded nut that connects to the diff? Is it because you're worried that it will vibrate after or just a pain in the ass to break the nut loose? Cause to me it seems like way less work to just undo the driveshaft compared to dropping and re-installing the whole rear end again.

When I first started to disassemble the M3, I put a crows foot with a pretty long breaker bar on that rear nut and was not able to get it to budge. Actually the parking break slipped before the nut did. I'm fairly low to the ground and leverage wasn't the best. If I had to, I'm sure I would have found a way, but since I really didn't need to it was much easier to just leave it be. Since I had just done it, dropping the rear subframe was fairly easy to do again.

[attbimmer]

Got back from my trip today and had just an hour or so to look at the car. Since the M3 was now running I swapped places in the garage so my current daily is easier to get in and out. Prior to connecting the battery again I decided to put in the REM and upper front light / sos switch module just so that all the electronics are from the M3 so I could see what was/wasn't working in that state. After doing that I still have some odd things not working including: overhead lights, power windows, key remote, SOS button. Seems odd as this stuff is all direct from the M3 and no work g for it was touched aside from the lights, but that was just for the wiring from the front to the back lights and nothing to the FEM.

When I connect ISTA and read faults I can see several LIN errors related to that area. I'm sure they are related and not all independent issues, so will have to look around more to see what might be causing it. I ran through all the fuses quickly and they are all good. I found one bad, but it was just for a 12v outlet. I looked at the FEM just to see if anything happened to be loose there, all was connected correctly. Only 2 wires were added there for extra washer motor and the wire for the rear hatch.

Aside from this group of faults most other items are expected due to some things still not connected. I'd like to figure this issue out first before I start doing any other coding changes.

There was one fault for break switch continuously on, which I checked and was just the sensor not quite snapped in right. Easy to fix that one.

I also found that I will need to get a new front light / switchs module since the one from the wagon is missing the sensors for the alarm and the one from the M3 is missing the sunroof switch. Not sure the 2 can be combined into one, but I guess I can look into it.

These are the current faults:

[attbimmer]

So tonight I started looking more into what could be going on with the key not being detected. Since there was a specific fault for the remote receiver not being found (D90D01), I started with what does that module actually look like and where was it on the M3. Turns out it was a small module that is in the middle of the car under the center rear part of the rear glass. I looked back at pictures I had while taking apart the M3 and sure enough it was there, but I couldn't recall where I had put it. For a minute I was afraid I had misplaced it, but then thought I wonder if it is still in the M3. Went out side and look what I found:



Based on the position I knew exactly what wire it should connect to, so I plugged it in and what do you know, the key was detected and all worked again. Lock/unlock work with the fob buttons and CA worked as well.

Also as a bonus all windows started working as well except for driver door up. Pressing the button down I can here a click, but nothing going up, so will need to look into that more. Still though that was a nice item to get working. I'll need to see where I should install that module. Will need to look back on where it was in the wagon.

Next will need to figure out what is going on with the whole lighting, sos, rain sensor, ... I don't think that will be quite as easy.

[attbimmer]

Not feeling like looking at more error codes and only having about an hour I decided to extend the wiring for the rear camera tonight. I found some similar shielded wiring used by BMW and ordered it a few weeks ago and it arrived last week while I was gone. I used it and extended the harness on the lift gate side, plugged it in.

When I went to check it the car complained that trunk is open, so no rear camera view available. Since now had the opener button connected I tried pressing it and the close mechanism worked. I didnt have the latch hookinstalled yet on tail gate yet since I didn't want it to latch until the electronics were working. I installed it and tried again and the lift gate closed and latches on its own. Opening also worked via the lift gate button and the front foot well button. I connected the close button on the lift gate as well and that worked as well. The button to lock and close did not work yet, but that is expected since the M3 didn't have that and will need coding.

Anyway that's another thing working and now that the lift gate was able to close and latch properly I checked the rear camera again and it worked. Nice couple more items working in a short time and another step towards a fully functional car.

[jaylazy2020]

Originally Posted by attbimmer

Not feeling like looking at more error codes and only having about an hour I decided to extend the wiring for the rear camera tonight. I found some similar shielded wiring used by BMW and ordered it a few weeks ago and it arrived last week while I was gone. I used it and extended the harness on the lift gate side, plugged it in.

When I went to check it the car complained that trunk is open, so no rear camera view available. Since now had the opener button connected I tried pressing it and the close mechanism worked. I didnt have the latch hookinstalled yet on tail gate yet since I didn't want it to latch until the electronics were working. I installed it and tried again and the lift gate closed and latches on its own. Opening also worked via the lift gate button and the front foot well button. I connected the close button on the lift gate as well and that worked as well. The button to lock and close did not work yet, but that is expected since the M3 didn't have that and will need coding.

Anyway that's another thing working and now that the lift gate was able to close and latch properly I checked the rear camera again and it worked. Nice couple more items working in a short time and another step towards a fully functional car.

In my view there are few cars that look better in red but for some reason a fast estate car seems to suit red. An Rs6 avant suits red for example.

But this F83 in red with the black interior(with the light coming in to the cabin via pan roof) and the shadowline 666 wheels just looks absolutely stunning!

[TouringM3]

My man - you're doing great and it's getting close!

[attbimmer]

Now that the rear lift gate is all wired up I installed all the plastic interior trim on it. I also found that it needed a small adjustment to better center the lift gate on the car left to right, which then put the alignment of the rear glass section a bit off, so the wiper motor needed to also be adjusted slightly. Of course to do that I had to pull the plastics back off, adjust and reinstall. All good now though and the light even work.



After that I turned my attention back to the front of the car. When it was originally repaired they used some random screws to attach the front bumper vs the correct ones. I had ordered the correct ones and they came in a bit ago, so I swapped them out. A picture few will enjoy, but it feels good having all the right hardware on it even if you can never really see it once the rubber seal is installed.



Also one of the latches for the hood was tweaked a bit from the past accident and both had chips on the black paint. I had set aside the latches from the wagon and they were in great shape so I swapped them in. Doing that also meant removing the top metal bar that supports the radiator / bumper and when putting it back on i was able to get a better sense of the right alignment for the front of the hood against the bumper. It all now fits pretty well so I installed the hooks that go into the hood and gave it a close. Left side was just about right, but right side was a little high still. I went to open it and only the right side popped. Oh boy, I thought. Luckily all the wheel well covers were still off and I was able to just lift the front corner a bit so that I could get my hand in near the latch and manually release it. The cable housing for the release wire must not have been securely in its spot and had come loose. I put it back in tight, adjusted the hood and over all we are good. I now no longer have to listen to the car constantly bong at me that the hood is open.




I had somehow misplaced the nuts for the wiper arms. Looked through my labeled baggies twice before and didn't see them. Looked again today and found them, right where I thought they were previously. My eyes must have been playing tricks on me before. Anyway, wipers are in now as well.



These aren't exactly the most exciting steps, but each is a step closer which is awesome.

Rear bumper still isn't ready and also still waiting on parts, so will probably be another couple weeks.

[attbimmer]

Not much time today, but I did put together the left side rear bumper carrier. I did the right side a while back when I was working on the bumper cover and just never ended up building the left side. It isn't particularly difficult, but is tedious since it is hard to tell exactly where to cut to join the 2 parts. It is a lot of trim, test fit, trim, test fit, ... until it fits right. Most of the carrier from the M3 is used (white) and just the top corner of the wagon carrier (black) is used near the tail light. To join them I used used hot staples and then plastic welded over the joint. It is quite solid and should hold up well.

[attbimmer]

The last few nights I started looking at coding for the wagon specific functions. Thanks go to scotty737 for tips on the method to follow. It took some playing around, watching some videos and reading a few posts, but end result is I was able to code the functions for rear lift gate open/close, rear glass opener, rear wiper, ... I'll post a more detailed message later that goes through the specifics.

I also connected all my PDC sensors and was relieved to find they were now all working. When I got the car there was a fault in the front and after checking the front harness back then it looked to have been repaired incorrectly. A new one from BMW was only $50 so I just replaced it and am glad to see that was the issue.

I also had an issue with the interior cieling lights not working. After far too much retracing wiring only to confirm it was all fine, I went again to check the fuse. It was fine when checked from above (I had checked every one a few weeks ago), but I saw it was not a factory fuse so I pulled it out. There was some build up on the contact that looked a little like light corrosion. I replaced it with a spare one and now the lights work fine.

Fun stuff, a few more faults left to trace down, but getting close. I've got a bunch of parts coming in this weekend or mid next week and I heard the rear seat back is done. I'll be away again this weekend so won't be able to get back to it until next week, but should get a lot of more buttoned up then.

[TouringM3]

Hey attbimmer
Something i want to share from my recent experience ... if your paint shop sprayed over the mounting bolts for all the rear trim pieces (bumper carrier & supports, tail lights, etc...)

I cannot recommend this enough. Take a bit of paint stripper, soak the threads, and wire wheel or wire brush off the paint.

Why, you may ask? Well, I didn't do this, and then after having the car assembled for a good 2 years once i started to disassemble to do some adjustment work the dried paint in the threads acted like red loctite and i sheared off a couple of the threaded studs.

Hope this is helpful!

[0NIN]

Do you know if it’s possible to have comfort access work on the tailgate?
I’m currently organising my own F81 build and if it’s possible for CA to work I would prioritise finding a f31 that has it
Cheers

[attbimmer]

Originally Posted by 0NIN

Do you know if it’s possible to have comfort access work on the tailgate?
I’m currently organising my own F81 build and if it’s possible for CA to work I would prioritise finding a f31 that has it
Cheers

Yes, it works already.

[attbimmer]

0NIN - I don't think you really need to find a wagon with CA. I used everything from the M3 for that. The wagon parts were just the actual latch and opening mechanism + plus control unit for the lift gate.

[attbimmer]

Ok, so here is more details on the procedure I followed to determine the differences I need to apply to correctly code F81.

1. You will need a laptop with e-sys and bimmer utility installed along with an enet connector to the obd port.

2. Connect e-sys to the car and then go to expert mode and then coding. Under vehicle order, do read and then save. Then under SVT to the right do read ECU and then save.



3. Now go to bimmer utility and select FA editor. Select open and then save the vehicle order xml file that you saved in previous step. It will show M3 plus all the options codes.



4. Now change the vehicle type to an F31 (I used F31 328 N20 USA) and save it to a new file labeled with F31. Then do the same for an F30 328 and save it as well to another new file labeled for F30.



5. Now go back to e-sys and go to expert mode coding verification. Under vehicle order load the F80 VO xml that you saved in the 1st step. Then under Complete Verification select verification by SVT and open the SVT file you also saved in step 1. Then in the lower right select NCD trace and pick a folder for trace directory. Name it something like F80_original. Then select complete verification.



6. Now repeat step 5 for the F31 and F30 VO xml files. Leave the SVT file from the F80 for these steps. Pick new trace folders for the F31 and F30 outputs and run complete verification again for each. In this step you are creating coding parameters for each control unit in the car with the options on the M3, but as if it was an F31 and F30.

7. Now make a copy of the F80 NCD folder you created in step 5 and name it something like F81. This is where we will start to save the merged files that will include the changes needed to add in the wagon specific functions.

8. Now go back to bimmer utility and select NCD compare. Open the NCD file for one of the control units you will need to code, such as the FEM, or REM from the F80 original directory. The files are all saved by control unit number, not name. You can look control unit names in e-sys to map the name to number. For example the REM is 7A1. Then select the NCD file for the same control unit from the F31 directory. The differences found will be displayed. Save the differences to a file and repeat the process for each control unit that will need coding. After doing compare for F80 to F31 do it all again for F80 to F30 and save all the compare files. We are doing this to help differentiate between what is unique to the F80 and F31 and weed out what is F30.



9. Now bimmer utility doesn't let you do a 3 way comparison, so to avoid doing it manually I just took all the difference files for each control unit and asked chatGpt to analyze them and weed out the differences. It provided me a table per control unit that showed the values across all 3 body types for each parameter. This is an example of one of the tables it produced. You can see each parameter and the different values that are set for each body type.



10. Now for a lot of the parameters it is hard to tell what they are for just looking at the parameter name. To get more details on each one you can go to FDL editor in bimmer utility and open the F31 NCD for each control unit. Look for each attribute from the differences table created in step 9 and for most it will show a description of what it is for or what it does. I then added this information to the tables I created in step 9.



11. Now go back to NCD compare in bimmer utility and open the NCD for each control unit need to code from the F81 directory we created earlier in step 7. Then open the same control units MCD from the F31 directory. For each of the items you have determined from the diffs that need to be added to the F80 to make it an F81 you can click on it and copy it over. When you copy it it will be saved right away. This is why we are doing it in a new directory so that we keep a clean copy of the originals.for easy reference back.



12. Now you have NCDs with the changes applied and they can be coded to the car..you can do that with bimmer utility or e-sys.

There will definitely be some trial and error to this since it isn't 100% clear what each item is for, but for the main things it wasn't too hard to figure it out. I'm sure there is still fine tuning as well beyond just getting basic functions working.

Also for me I wasn't doing any additional modifications at this time. I just took the F80 as it was optioned and just added the F31 items required to get everything working. If you were to retrofit other options as well there would be more to change. I may do that later on for some things, but wanted to start with a clean baseline and then will go from there.

Anyway hopefully this is helpful for anyone doing something like this in the future and thanks again to scotty737 for the tips he gave me on this.

[0NIN]

Originally Posted by attbimmer

0NIN - I don't think you really need to find a wagon with CA. I used everything from the M3 for that. The wagon parts were just the actual latch and opening mechanism + plus control unit for the lift gate.

Okay maybe you can check your tailgate, according to realoem there’s a few extra bits and pieces for CA

Also awesome write up for the coding of the rear tailgate functions!