Megasquirt-Parts needed for 325E with wasted spark

[joecrotch]

Good evening This goes out to all the eta Megasquirt guys or anyone else who can answer.

Here is what I ordered.
MegaSquirt-II Engine Management System w/PCB3 - Assembled Unit
24" MegaSquirt Pigtail Harness
MegaSquirt Tuning Cable (DB9 Straight Thru)
USB to Serial Adapter - Works with TunerStudio!
MegaSquirt PWM IAC Valve Control (TIP120) 'Mod-Kit'
Wasted spark stuff

I am finally taking the plunge and ordering my Megasquirt. I know with the eta you need to add the trigger wheel and sensor. My question is to get it up and running what else do I need. My plan is to get it running on MS before bolting on all my turbo parts. So I am going to list exactly what it is I am going to do, please tell me if I have this right.

First off I will cut my ECU harness off and using a pinout schematic find all the wires needed and match them to the corresponding wires on the DIYautotune harness. being that it is a "e" there is no reference sensor or trigger wheel. From what I understand the CPS on the trans does not work with Megasquirt. So I also ordered a "I" sensor, trigger wheel, and timing cover.

Other than that is there any unique mods I need to do like the trigger wheel since this is a E car. I have read more about Megasquirt then I can handle lol. I just want to make sure what I understand is actually fact. or just me making shit up in my head!

Thanks for any help!!

Joe

[blood_sweat_&_gears]

This past week I just did what your about to attempt. First off let me just state that my end goal was to do a 2.7i turbo build. If your confident in your wiring skills go ahead and wire it up yourself. I have an 85 eta and based on my research the amount of info available for the eta compared to the 325i is very little. I personally bought a 325i motor as it was much cheaper than sourcing the crank position sensor, toothed wheel, low km head, and it really cleaned up the engine bay. The 325i harness is almost plug and play with the MSPNP2. The only modification was rewiring the c101 connector. Other sensors you will require/want are an IAT from a GM and a TPS from an e36... I believe. I just went to the scrappers and got it all for $5 CAD. The TPS needs a mounting bracket made up. I used the old TPS from the eta and made one. Because I had a spare harness at this point I was able to chop a few of the connectors off and wire the sensors so that they too were plug and play. The reason you want a e36 TPS is because the m20 TPS is ON/OFF. This means the ECU can only tell if the TB is open or closed. The E36 TPS can tell the ecu position based on amps which are then scaled to a percentage value. The GM IAT is required because your existing MAF will not be able to handle the turbo. It is super easy to install. All this sensor does is feed the ecu a resistance value which is translated to a temp. Another thing to consider is the Eta injectors are low impedance, where as the 325i are high, so I'm not sure how those will work with megasquirt. Again because I had the whole motor I just swapped in the 325i injectors after bench testing them first. Its defiantly a smart move to jump over to wasted spark. I was forced to because after cleaning my distributor cap contacts, the rotor no long made good contact and the car was only firing on 2 cylinders. This is where I am at this point in time. I purchased 3x MSD coils and mounted them on a GM base from a v6 Grand Prix. You also need a QuadSpark which was news to me as of yesterday. Apparently the MSD 8224 coils don't have built in igniters and require an external igniters. Anyways I hope this helps a little. This whole week has been a huge learning experience for me and so I hope that I can help you as the rest of the e30 community has done for me. PM if you have any questions.

[joecrotch]

I actually forgot to list the TPS and IAT sensors. I was aware of those. I was not aware that I needed quadspark. I was planning the same, MSD coils and a GM base. I will look into this. So let me get this straight, you had to do some rewiring on the c101? Do you have a write up on your install. Or can you be a little more specific about what I need to change?

Thank you so much for the help!!!!

It almost seems like buying the non PNP MS2 and building my own harness would be easier.

[blood_sweat_&_gears]

Oh ok right on. Ive always wanted to do a build thread but never got around to doing it. I'm happy to help though. The reason I had to rewire the c101 connector was because the plug used on the 85 harness is not the same one used on the 87. This is the pic I used: http://i.imgur.com/tuhjQ9k.jpg To confirm everything continuity check before installing. I used painters tape and labeled every connector on the harness then went to town with a multi-meter. It appears that megasquirt has the igniters included so you don't need a quadspark. Mine didn't have them so I needed one. I would highly recommend you crimp your connections, not solder. I soldered mine and have had a few cases where the solder has cracked just from reinstalling the harness. The small wires are fine but the larger gauge wires keep cracking. You may be right building your own might be easier but I cant say for sure.

Installing the trigger wheel is pretty straight forward. Getting the fan off can be a bit of a bitch if its never been off before. I made a tool to hold the fan and shaved down a 1 3/4" (??) wrench which made the job painless. Make sure you chase the threads on the block where the sensor mounts. Its a M8x1.25 tap. Also dont over tighten the harmonic balance bolts. I had an "oh shit moment" when one of the bolts went from tight to very loose while tightening it. The bolt cracked but i was able to extract it luckily. :up:

[joecrotch]

So Just a update on this. I actually sold the MSII and bought a Microsquirt. I saw a few builds with it so kinda excited to play with it. The only thing I am having trouble understanding is the batch fire injectors. Since its Microsquirt I think I am understanding that I need to set up 1 batch 1,3,5 and the second to 2,4,6 ?

Also I was reading an old thread and someone was mentioning a cylinder id sensor? Anyone know if this is needed and how to add it?

[varg]

To do "semi-batch" fire where the groups of 3 fire separately, the MS needs some way to determine which cylinder is firing. That's what that little sensor on one of the spark plug wires of late model E30s is for; motronic is using the signal from the inductive loop on the spark plug wire to determine which batch of 3 injectors to fire. Your car might not have that sensor and wiring in its harness, so you'd need to add some manner of camshaft position sensor to the engine to get the split batch. It's probably not worth the hassle to be honest, it might improve idle quality and low speed low load cruise a bit, but might wind up being unnoticeable.