Alright, so last night a couple friends of mine who have significant experience with MS and myself all put our heads together a figured out everything needed to run MSII V3.0PCB on a 7mge (NA).
It’s actually quite easy and does not require any re-wiring of the stock harness at all. The idea is to keep the stock wiring harness untouched so that everything can be put back to stock if need be. So without further delay, here it is…
The harness:
-Use the Noppondenso 52 pin BOB from diyautotune which connects the DB37 MS cable to the stock harness with plug and play ease. Can be found here:
http://www.diyautotune.com/catalog/diybob-breakout-adapter-nippondenso-52-pin-p-413.html
Fuel Injection:
-Stock harness/ecu runs 3 batches of 2 injectors at a time.
-MSII cannot do this without some complicated modifications to the MS (only has 2 injector outputs), so you can just run all 6 injectors at once on one batch. This should not cause any issues. Many manufacturers run their engines like this from factory. We ran our 4agte (4agze converted to turbo) like this for a long time with zero issues and zero fuel economy issues.
-MS3x will allow you to run 3 batches of 2 injectors just like the stock ecu. however, I have MSII so this is the way it must be done.
Ignition, Crank/Cam Position:
-In the dizzy there is a sensor wheel array with 3 VR sensors.
-The MSII only has one VR input. To achieve proper resolution, we need two of the VR sensor inputs. The “NE” and “G2” or “G1”. I’m going to use NE and G2. You can see these here on page 9:
http://www.turboninjas.com/mk3supra/1990/indiv/10_IG.pdf
-This requires building a 2nd VR input circuit on the proto area of the MS PCB. It’s only about $10 worth of components and is fairly simple to construct. The schematics and list of necessary components for this can be found here:
http://www.msextra.com/doc/ms2extra/MS2-Extra_Ignition.htm#2vr
IAT and Fuel Pump Signal:
-These are in the stock AFM and need to be addressed since the MS has on board MAP and the AFM is no longer required (One of the main reasons for going MS).
-The fuel pump switch can be easily fixed by a simple jumper on the correct pins of the AFM connector.
-The IAT sensor can be replaced with a GM CLT/IAT sensor which can be found here:
http://www.diyautotune.com/catalog/gm-closed-element-clt-iat-sensor-with-pigtail-p-58.html or in a junk yard. Just mount this IAT sensor somewhere close to the TB on the intake piping or thread it directly into the manifold after the TB (remove the IM before you drill and tap to prevent metal shavings going in your engine).
-A dedicated vacuum line for the on board MAP sensor on the MS can be run from the IM or you can T-in to one of the existing vacuum lines. Just make sure it’s a clean vacuum line that reads pressure from the IM after the TB.
-Hang on to the AFM just in case you need it again someday.
Wideband O2:
-There are several options here. I have not yet figured out which route I will be taking but here are the options I have at the moment:
-Use an Innovate MTX-L and wire it in manually to the MS.
-Use an Innovate LC1 which will plug into the stock harness O2 wiring and thus to the MS via stock O2 input.
-The other option is to leave the stock narrowband in place and run a 2nd wideband O2 for tuning purposes.
-The only extra wiring will be if I want to run an A/F gauge, which I will be running for sure.
That is pretty much all you need to do to run an MSII/3x on a stock 7mge (NA). This will allow the stock harness to remain untouched and thus, the ability to reinstall the stock ecu and AFM at any time and run the car as usual. For those who want to get rid of the barn-door AFM, this IMO is a better option than a MAFT Pro translator and MAF as the MS setup will give you full tune-ability and data-logging for not a whole lot more money.
All that is left to do is execute this setup. I will post up the results and any other issues I run into.
If there is anything I have left out, or if you have any questions, please post up and let me know.
Cheers.
