Converting Waterboxer to Megasquirt

[[email protected]]

I thought I covered this already.

First, call up Mario at Thedubshop.com and tell him you want to convert your Vanagon to MS. He can supply the ECU, harness, sensors, crank trigger, etc. He got the parts together for mine. I also bought his coil and plug wire pack, and the coil harness and plug. I had to shorten and assemble the universal plug wires. I also changed to a resistor spark plug to reduce ignition noise (it was recommended to do so).

My most difficult issue was R&Ring the crank pulley, since the new one needed to have the crank trigger wheel on it. I don't have the factory tool to lock the engine, so I had to remove the muffler, and use a compact impact to zip the pulley bolt off/on. I think spec is 217lb/ft, you aren't going to get that off with a ratchet with the engine installed.

I chose to build my own harness (no 30yo wiring), but I did get the mini-harnesses for the crank trigger, Intake air temp, and coolant temp from him. I re-used the wiring (2" long) for the injectors, PCV heater, and fuel pump. My harness took 3-4 hours to make, but a lot of that time was just staring at the parts. No rush, right?

I will post my A/F map and timing map when I have time. That will get you very close.

I have no doubt a idle switch would be a benefit, but I didn't need it. Idle is steady, regardless of temperature.
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[xoo00oox]

Nice job.

[leebh1975]

How did you wire up the tach? I assume the Vanagon has the high-current type. The MS2 hardware manual is a little confusing on how the tach is connected, but I've only glanced over it. Was any calibration needed to get it to read accurately?

[leebh1975]

Also, did you setup one bank for all four injectors like the Digifant has or did you setup two separate banks like the wiring diagram in the MS2 manual? If you did two banks, how did you set the them up? It seems like injector pairs 1-2 and 3-4 would make sense for wiring, but the firing order is 1-4-3-2. I guess that works.

[AndyBees]

The Mega Squirt system may be different than the Digifant System relating to how/when the injectors are queued to trigger (inject).

On the Digifant system, I don't think it matters how the injectors are wired. All injectors trigger at the same time with each signal of the dizzy/hall through the ECU on the ground side (one circuit ties all 4 injectors back to the ECU on the ground side). In the circuitry, the fuel pump relay provides current (12 volts) to the fuel pump, the injectors (same circuit), OX sensor, idle stabilizer, and power steering pressure sensor.

Fairly simple.. one complete rotation of the dizzy (two rotations of the engine) all injectors are triggered (inject). Injection volume is determined by the ECU based on a number of things, such as air temp, accelerator position (MAF), ignition advance, coolant temp, etc.

For what it is worth, I've been studying both the Digjet and Digifiant sytems to apply to an in-line 2.2 5-cylinder. And, as I stated in a previous post, I've inquired with folks at Mega Squirt about a system for my 5-cylinder.
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[leebh1975]

I've pretty much built my MS2. The only part that I'm not sure about is the tach output. It's a little confusing the way the manual describes building the circuit. One thing it mentions is some older tachometers need the high current spike from the ignition coil. I assume that means the Vanagon tachometer needs the spike. Do you know how that circuit was built in your MS setup?

[[email protected]]

My tach didn't work out of the box, with the MS configured for it. I don't know why.

I futzed with it for a while, and decided to just bag that and simply used a couple diodes and trigged directly off the 2 coil outputs, to the tach wire. That fixed it.
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It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

"Like" our Facebook page at
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and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net

[akmush]

Boy, this thread sent me off "down a rabbit hole!" I had never heard of the Megasquirt conversion and after a couple nights of reading online I feel like I am just a bit more educated. Also spoke at length with Mario at the Dub Shop.

I fall into category of original poster. 85 Weekender with 1.9. I have struggled for years to track down lingering issues of dead spots in the power band and inconsistent running. The Samba has been a huge help but after literally dozens of hours the problems remain. (grounds, AFM, ECU, the wiper board thingy been there done that.) Engine conversion is not in the cards in the near future but Megasquirt conversion could be budgeted for.

Some lingering questions-

-Megasquirt or Microsquirt? I understand the difference but am struggling to evaluate which would be the best for my purposes...

-Tuninig? This is the part that intimidates me the most. I don't have access to a Dyno and have never programmed an ECU. Sounds like there is a whole world of tunes out there but not specifically for water boxers...

-My 1.9? all available reading has been about the later 2.1 Diji jet. will this system also work with the FI system on my motor?

[AndyBees]

The guys at Megasquirt say they can make a system for any engine.

The Digijet and Digifiant systems are most likely interchangeable between the 1.9 and 2.1 engines <<< That assumes you would move "everything" from one engine to the other, including the wiring harness and ECU. From my research, it's my understanding that the Injectors are the same.

I have no clue if the ECU of a Digijet or Digifiant can be programmed. However, from what I've read, the Megasquirt System is programmable!

The Digijet system on my 84 (before I installed the TDI engine) worked just fine. I was impressed with it. Prior to the 84, I owned (mothballed now) an 83 Air-cool with a different system. It was basically trouble-free for over 200k miles. I've had a lot of issues with the Digifiant system on my 89... It's the one I'd like to install the 2.2, in-line 5-cylinder with a Megasquirt System...
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[zx11pilot]

This is such a great thread, I thought I'd revive it for the holiday season! Any updates on the MS system as installed? Wonder what it would be like to use this setup with a coil-on-plug setup, or would that be overkill? Anyway, I look forward to seeing some graphs and maybe an update too as to how the system is performing at this time.

[pushkick]

i have been interested in the megasquirt system for awhile and reading this thread i would like to know if the collective knowledge of the the application of megasquirt system to a 2.1 waterboxer could be managed to benifit everyone. i know i would like to be able to purchase a system and replace the existing digifant ecu system. since people have already developed a workable system using megasquirt i wonder if they would be interested in selling their design for a price. and provide a list of needed developments. some of us may be willing to spend some time to help where we could. having an installable system that the average person could implement. and a system that can be programed or modified by the van owner would be great if they so chose.
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[leebh1975]

I finally got my engine started yesterday. It has been a slow process of doing a rebuild and building out the MS system (with a job and kids and stuff). I still need to do some work to get it running and idling properly.

My build is very similar to this one, but I also did a rebuild at the same time. I built a Rocky Jennings (had him condition my block and send me the parts so I could build it myself), 2.3L with the tencent cam and tuned exhaust.

I would love to work on writing up something that would help other people build their own. I built everything on my MS. I got the kit and soldered everything together with the specific circuits I needed for the idle control and the ignition components I decided to use. It could probably be tweaked a little. RMW has some of the VW connectors, so I managed to get everything connected into the original harness without splicing into wiring and stuff. I wanted to be able to drop the original Digifant back in if anything went awry.

[a1fa]

leebh1975, very good. What settings did you end up using for injector dead time and voltage correction?

Another member sent me injector settings out of digifant which included injector dead time and voltage correction if you need it.

Make sure your battery is calibrated correctly. Use volt meter to make sure voltage at injectors and megasquirt is the same megasquirt reports in tunerstudio.
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Learn to ride. Ride to learn.

[leebh1975]

[leebh1975]

Does anyone know what the actual injector size is in lbs per hour? I found a site that said they're 16.1.

[a1fa]

185cc/min
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Learn to ride. Ride to learn.

[leebh1975]

[10degnorth]

Awesome thread, and now I’m seriously considering a microsquirt swap. I have a couple questions for those of you that have completed the swap or are generally knowledgeable on the subject.

1. What does your MPG look like number wise?
2. How about power increase, is it noticeable?
3. Would I get good results using a MAP, IAT, TPS, and pulling my tach reading off of the coil?
4. Are there anything things I should consider adding?

Thanks so much for the help.
_________________
1984 Wolfsburg Vanagon (Current Project): https://www.thesamba.com/vw/forum/viewtopic.php?t=773912&highlight=

1988 Microsquirted, Wolfsburg Vanagon (Sold): https://www.thesamba.com/vw/forum/viewtopic.php?t=708000&highlight=

Microsquirt Conversion Guide (Work now Discontinued): https://docs.google.com/document/d/1laXykNPbRYS8MT...2imqd2pnx7

[a2wolfsburggli]

I had read this thread a couple weeks ago as I was contemplating a megasquirt. The going rate for a new ISM is 200+ and as long as I'm gonna be that far into ignition / fuel electronics I may as well stick it into a modern system.

I contacted DIYAutoTune and this is the setup they quoted:

[leebh1975]