The E36 M3: A masterpiece of engineering that could only have been created by the kind of mind able to focus on a singular purpose to the exclusion of all other consequences. Unfortunately, the example that I found had suffered unfathomable, intentional abuse at the hands of a ruthless tyrant that brought the engine to its knees faster than a central European country in September. So as usual, it was the Americans to the rescue with a crude but incredibly powerful, highly effective solution. More than midway though the project, I was tying up loose ends and approaching the day I could finally fire up the car and drive it. A sort of Drive Day, if you will. D-Day for short.
You’ve probably figured out by now that I’m the type of person that, if I want something done right, I do it myself (my wife sees both pros and cons of this stance). So when it comes to engine management, why would I let someone else fiddle with my settings? Why should every change I make to the engine setup necessitate visiting a dyno shop for a retune or emailing some faceless entity on the internet so they can make a guess and possibly even charge me for the pleasure?
Absolutely I will be doing this myself. But what should a virile man-about-town with little sense and even less spare cash do for an ECU? Well, Megasquirt of course.
But what makes the Megasquirt so cheap? Well, a couple of things. First, it’s available as a DIY kit, meaning that if you dare, it shows up at your doorstep as a circuit board and a bunch of drug dealer baggies of electrical components. That alone saves about $180 over the fully assembled version of the kit. However, one hundred percent of my soldering experience was primarily poorly cold-soldering wires together while installing car stereos, so I can’t imagine how assembling legitimate electronic components together in an application on which my life literally depends could go wrong. At all.
Secondly, Megasquirt, in general, takes
some a Freaking Lot of research, configuration, and customization, especially in generic kit form. This holds true for assembly, installation, and configuration. If you think the sexiest Friday night imaginable involves spending three hours reading about an enhanced wall-wetting-based acceleration enrichment algorithm, three more hours trying to implement it, and then ending up with a worse-running engine, then not only is Megasquirt perfect for you, but I may want to marry you.
So being the savvy, cost-conscious (read: cheap-ass) consumer I am, that’s the direction I went. I bought a Megasquirt MS3 kit, an MS3X expansion card, and pre-made 10' wiring looms, all to the tune of about $800, noting that $160 of that was the premade, labeled wiring looms which were a splurge. As far as I can tell, that’s about half the cost of any other aftermarket ECU solution, and not out of the ballpark of buying some kind of tuning device for a factory ECU and paying for a tuner to do his dirty business, but without gaining all of the additional features offered by an aftermarket ECU.
Given that my soldering iron finesse could be summed up by that time I left my Radio Shack soldering iron plugged into the wall overnight and my roommate’s dog burned her nose on it sniffing the tip the next morning, I knew I would be out of my league trying to jump right into soldering an entire ECU. So I also purchased the two “JimStim” stimulator test kits (one for the Megasquirt, one for the MS3X expansion board); the stimulator is used to generate input signals that simulate signals from a crankshaft, camshaft, coolant temperature sensor, wideband O2, and more to test out the ECU kit’s circuits once assembled. As an added bonus, assembling the stimulator kits is good soldering practice on something that’s not as “mission critical” as the actual ECU.
So I picked up the cheapest soldering station I could find online (are you sensing a pattern of potentially destructive behavior here?) and set up a little soldering station in the kitchen.
Nothing like spewing lead vapors and debris all over food prep areas.
With that, I started in on the two stim boards.
With those under my belt, I started in on the ECU’s main board.
And once the board was completed, it was time to test and make sure all of the voltages were where they were supposed to be and that all of the smoke stayed in before inserting the CPU card.
After passing that test, I went ahead and installed the CPU card and MS3X expansion card, then loaded the firmware.
And tested communication with the PC and Android apps:
Next was wiring the Megasquirt up to the real engine. I lopped off the engine’s original harness connectors, printed off a wiring diagram, and got to labeling.
I pulled out all of the wires I no longer needed - anything transmission or emissions related was gone, as was plenty of other fluff.
With only the essentials remaining, I paired up the engine’s wires to their counterparts on the Megasquirt harnesses.
I found a base tune for a 5.0 engine on DIYAutoTune’s site. It was set up on a 1993 Mustang with a stock short block, GT-40P Explorer heads, and an Edelbrock intake. That would pair nicely with my Explorer engine so I made the necessary adjustments to account for my injector size (36lb. vs. stock 19lb.) and I modified the ignition configuration to use my Explorer cam sensor and crank wheel to drive the LS coils sequentially.
With everything wired up and configured, I was able to power up the engine’s circuits and the Megasquirt via a spare battery and calibrate the intake air temp sensor, coolant temp sensor, and throttle position sensor. After that, I was able to use the starter to turn the engine over at cranking speed and confirm functional crank and cam sensors. Except that the test didn’t confirm a functional cam sensor. So I pulled the sensor off and found this:
I was able to find a replacement sensor and “camshaft synchronizer” (what would normally be the drive shaft for the distributor) at a local parts store in stock for $36. Score another point for the domestic engine.
With that in place and the engine in the car, it was time to integrate the Ford engine with the BMW chassis; on the cusp of the pivotal moment in any engine installation, but especially one where the engine was never meant to be there. But was the slender German body ready for what the brutish American engine had in store for it? TUNE IN NEXT TIME.
Edit - I do hope you like the new post title, Mr. Vroom.
Catch my build thread here on Oppo with a new installment each Monday, or if you like spoilers check out MikaelVroom.com for the latest updates. Twitter me @MikaelVroom, Instagram me @MikaelVroom. I think we can all agree after last week’s post that me not making any “MegaSquirt” jokes is quite a feat.