M42 ECU Conversion: Link G4X/E36X

[bmwman91]

Yeah, I'd believe that maybe you needed to bend it a little. I think I have it all figured out now with all of the 3D printed brackets, so we'll see how things go.

[bmwman91]

I got the stock M42 knock sensors today and did a quick fit check. These are definitely going to fit better, and I can keep the oil sensor in the filter housing.

Here is how a stock one fits with the wire exiting toward the rear, which is how I think I want it to go so that I can install the receptacle in the bottom of the wire box and have the sensors plug right in. Even with the other stuff in place, it is not interfering.




Here's how it looks with everything out of the way.




I could also turn it around and have the wire come out the front, so I have that as an option if necessary.




Here is a comparison between the M42 stock sensors and the KS4P sensors I had initially wanted to use. The stock ones are actually slightly larger, but having the integrated wire makes it a lot shorter overall.






Also, I put together one of my little wheel speed sensor boards. Unfortunately, I mixed up the footprint for the 5V regulator and fried it instantly lol (you can see the little burn spot where the magic smoke escaped). I corrected the issue and ordered a new set of boards. After removing the regulator and just powering the thing directly with a 5V supply, I was able to verify that one of the conditioner chips was working correctly, but the other one got cooked. Oh well, live and learn, and double check the datasheet!

[bmwman91]

Today I sucked it up and made a little bit of an oily mess to test fit the PST-F1 and make sure that it would clear the knock sensor. At first I tried to eyeball the fit, and came up thinking "oh sh*t" when it looked questionable lol. So, I removed the oil pressure switch, tried to control the oil drainage (I'd guesstimate that ~6oz came out before the "clean" side of the housing emptied out) and installed the sensor. It was close, but it clears the knock sensor with the connector and boot.

I don't entirely like how far out of the oil flow the thermistor tip is when using the thread adapter. It is probably 35-40mm away from where oil flows, and that's a lot of stagnant oil. Now, the housing is aluminum and conducts heat well, and has the full volume of oil flowing through it constantly, so I think that it should heat up to full temperature pretty well, but the response will probably be a little slow and I worry that it will cool off at highway speeds. I have a spare housing that I was thinking of machining to allow the sensor to be 10-15mm closer in than it is with the adapter, but I also don't really want to have to pull my nice clean, new engine apart again lol. The oil filter housing is pretty easy to swap, but for now I will see how things go with the adapter. Worst case, the response is slow or gets cooled by passing air and I swap on the machined housing.




Here it is with a bit more light. The connector is sort of trapezoid shaped and in this orientation it has about the maximum amount of clearance. here it is with more light.




I then unscrewed it a quarter turn to get the wide side of the connector & boot aligned with the knock sensor, and I still had ~1mm of clearance. So, even if when this thing gets installed for real it aligns in this "worst case" orientation I will have clearance (more than this actually, since it will be at least 1mm further toward the housing when fully tightened and compressing the crush washer properly). The knock sensor definitely needs to be pointing toward the rear though, as it would interfere if the wire was coming out toward the front. Anyway, I breathed a small sigh of relief once I saw that things would fit well. I could have always bought myself 2-3mm more by eliminating the boot since the connector uses individual wire seals which provide some protection & strain relief, but I am happy that the boot will fit (it is an "extra" from a 3-position JPT plug from a hacked-up harness).




That's it for now. I have other non-car stuff I want to focus on for the rest of the long weekend lol. On the one hand I enjoy projects like this, but on the other hand I can get carried away with them and put way too much mental energy into them. I can feel that I need to take a step back and occupy myself with some other stuff for a week or two!

[bmwman91]

I fooled around a little today to finish up the ICV installation plans. Since the 3D printed brackets seemed to get it where I wanted, I had some little 3/32" mild steel bits laser cut for the final bracket. I will be sending these out for black powdercoating this week as well.




I have a little mini-brake that fits in my vise, and it was the perfect little tool for the job. I once used it to bend a 2" wide piece of 1/8" steel, and that was definitely the upper limit of what this thing is intended for. These little things were no problem at all though. I bent them, took them out to compare to the 3D print by holding it against it, put it back, bent it a little more, checked, etc., until it came out just right. The first one had a little oops in that I started bending it from the wrong side, but I straightened it out and proceeded to bend it the other way. Still, I could tell that the metal was getting a little fatigued, so it's good that I had 2 of them cut.




Here is the final part. They were fully deburred and polished on my pedestal buffer using a convolute wheel ("Scotch Brite wheel"), but since they are just mild steel they will be getting some nice matte black powder coating. If anyone wants to use an M50 ICV, shoot me a PM and I'd be happy to sell you the second bracket at a very reasonable price lol.




Using it to mount the ICV, everything was exactly where I wanted it.




The next order of business was to get the hoses sorted out. Thankfully, there is an off-the-shelf solution that only required a little extra work. HPS makes some silicone reducing elbows which also have a fairly tight radius. The following parts were used (you can also search the PNs on Amazon and get them from resellers for less + free shipping):
https://hpsperformanceproducts.com/products/hps-16mm-22mm-black-silicone-90-degree-elbow-reducer-reinforced-hose-htser90062087blk
https://hpsperformanceproducts.com/products/hps-16mm-1-inch-black-silicone-90-degree-elbow-reducer-reinforced-hose-htser90062100blk




I had to go through a few rounds of test fitting and trimming, but it worked out well.




Here is how they fit after I finished with the trimming:






The only "questionable" part of this was the fact that I ended up shaving the barbs off of the dummy ICV. I was able to get the elbows on over the barbs but it was a giant pain and the fit was not amazing after trimming them and having the barbs up in the start of the 90 degree turn. If the hoses were for high pressure fuel I would not remove the barbs, but this is just the ICV which is never actually under positive pressure, so hose clamps will be just fine I think. I will do a much better job of shaving down the actual functional ICV that I will be using.




The other thing I took care of was making sure that my MAF removal plans were going to work. As you can see from my setup, all I really need is a straight tube section.




And wouldn't you know it, HPS sells the perfect part. No need for any fabrication at all, other than a little de-burring of the sharp edges on the ends. This is the part:
https://hpsperformanceproducts.com/products/hps-2-3-4-inch-aluminum-joiner-pipe-tube-tubing-bead-roll-4-inch-long




Here it is installed. It will also be powder coated in matte black with the ICV brackets.




That's it for now. The remaining mechanical items for me to do are to machine the fuel line tee for the PST-F1 sensor and to machine the intake manifold for the PST-1 MAP+IAT sensor. From there it is all wiring harness construction.

[bmwman91]

It's been a little while since I have been able to get much done on this project as work has been extra busy lately and home life also has its demands. But, here's a little bit of progress.

Here is the M50 ICV after I belt sanded the barbs off and then smoothed things out with a convolute wheel. The silicone hoses go on a lot more easily now.




I got the powder coated parts back, and they look really nice in crinkle black. It seems a little coarser and glossier than what I had done on the adapter plate for my M30 air box, but a little dust and dirt should make the tube blend right in, and nobody will ever see the ICV bracket anyway.




The bigger thing that I finished was the quad wheel speed sensor conditioner. This one was properly laid out and works really nicely on my bench test setup. Noise rejection is good while still being VERY sensitive. I designed a little clamshell enclosure to 3D print for it which would keep it safe and integrate some little rubber grommets.








I kept it fairly simple and easy to 3D print. Initially I thought about integrating some little flexible snaps to hold it together, but tapping screws are a lot easier in the long run, and won't get brittle over time. Also, I would have had to change the print orientation a lot to make strong snaps, which would have meant a bunch of support material being laid down inside the enclosure, and that just makes a mess so I avoid it whenever possible.




It all came out nicely and everything fit well.






I had a small batch of PCBs made for this. Folks who want one for their ECU projects can PM me and once I have a feel for how many people are interested, I can order more components and assemble them. The automotive qualified parts, particularly the MAX9926's at ~$8 each, are costly enough that I want to know exactly how many I need to order.




Here it is all assembled, cleaned and sitting in its new home.

[gttechnic]

How do you propose mapping this aftermarket ECU? I don't know of a way to determine the factory settings. The way I would proceed is to run a basic map that you can download from LINK for this engine and see how it runs. I would then get it on a chassis dyno to set the various tables. I haven't done this myself, but I'm thinking someone in the Austin area can do this.

I'm sorry if you discussed this already, but I just view your post and it gets rather involved. I'm impatient.

[bmwman91]

Sorry there have not been too many updates, I am taking a break from this project due to work and family obligations at the moment. The E30 runs pretty well on stock management as well, so I am going to enjoy it for a bit longer, and I am due to emissions testing later this year, so I am going to keep it in the current state since I know it passes lol.

Anyway, as far as mapping I am going to have a professional tune made for it, probably by Sssquid. He has done the factory remapping for me and can probably "translate" a lot of it into a decent base tune. After that, I may just drive the car out to Missourri for some live dyno tuning. My experience working with a "real" tuner has made it clear to me that those guys are going to do a better job on a tune than I am since they have thousands of hours of experience with it and I don't, and they will get the tune done faster than I would too. It's well worth the cost. I'm not going with the Link system because I want to DIY the tune...I want the modern control features and improved throttle response it provides.

[bmwman91]

​Long time no update...

I am still not 100% back to working on this since I have told myself that I will finally deal with the full repaint this fall, but in the interim I have a little time to poke at the ECU project and do some basic legwork. As such, I finally planned out the wire arrangement for the main run that goes from the ECU to the firewall. It always irked me that the factory harness had some wires sort of twisted around one another, and there was a lot of "extra" wire here and there due to how mass production works with these things (harnesses are built out of sub-harnesses in most cases). Well, this sucker is a "too much time on my hands" special one-off, so none of that needed to be left in my new and improved one!

Now that I am 99% sure of the final ECU pinout, I was able to build a map for the ECU connector entry. Things will be getting a little tight in there, so there can't be any unnecessary crossing or layering of wires as they come in. The general idea is to separate wires by "type", and to have them stacked in a closest-to-farthest-terminal way which will be most space-efficient. I am not about to go crimping terminals on and putting them into the housing yet since I want to do that in the actual car, but it is also the case that I wanted to have the wire runs through the large sheath be approximately stacked in the proper order.

I built a little wire layout map based on the connection types and positions. All of the high and mid-current stuff is shielded, with the "S" wires being the shield taps that will be joined outside of the connector housing. Knock, crank and cam sensor wires are also shielded.







If anyone wants the vector art template for a mostly-properly-scaled 88 pin connector (Motronic side) and the mating connector entry opening, it is here:
http://www.e30tuner.com/assist/e36x/...e_Template.svg

So, I put together another basic pin board and got things labelled, sorted and arranged with an absolute minimum of twisting and crossing.







I am also going to re-design some of the sensor adapters and stuff. The previous ideas were nice and fancy looking, but too much hassle to actually make. I can get the job done much more simply. The main thing that I want to change is the oil pressure+temperature sensor position. I had been planning to install it in place of the stock oil pressure switch, which would be fine and could be done with a simple adapter, but the thermistor would be well out of the actual oil flow and probably read 10-20 degrees cool. At this point, I think that I will have a little mount boss TIG'ed onto the upper portion where the filter element is. Yeah, it is on the dirty side and if somehow the filter got clogged it would not indicate loss of pressure on the clean side (although the housing has an emergency bypass valve), but I don't plan to forget to change the oil or filter for 100,000 miles lol. An additional benefit of having the sensor up there is that I can use the Bosch Motorsport knock sensors since there will be room for the front one again without the oil sensor down in the way. The stock M42 ones are fine, but I would prefer to not deal with sensors that have integrated wires and which might go out of production at some point.​

[bmwman91]

I have been back on this project a bit in the recent month. Most of the updates are on r3v, but for anyone on here who has been following this thread, here's an FYI that there's progress! Check the thread on r3v for the latest updates.

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/alternative-tuning-w-a-r-megasquirt-etc/9961647-m42-ecu-conversion-link-g4x-e36x