So my car used to be MS-1 running parallel with a CAS retrofit. I upgraded to MS-2 and used AbeFM's PNP board. A few weeks ago, the car left me sit in a parking lot and all it would do was crank. I traced the problem to a voltage issue due to a sloppy solder job on my PNP board (done by me). Here's my issue. I liked how simple the parallel setup was when I was running the MS-1, but I like the accuracy and smoothness of the MS-2. My idea was to build the cam and crank circuits in the proto area of my MS, make some simple changes to my parallel harness, and then obviously run the MS in parallel again.
Has anybody on here had experience with this setup? How well did it work? I need all the input I can get.
Here is a schematic of the circuits. Does anybody have these parts I could buy off of em?

 

Why are you trying to run parallel, is this an emissions thing?

I am running parallel, but am feeding the stock PCM from the original cam/crank sensors and installed a vishnu 60-2 trigger wheel for the MS. I also just got a CAS to install for sync, so I can get sequential working.

 

So if you have a '99, why aren't you running the stock crank trigger?

 

The micorsquirt ran fine off the stock triggers w/o the schmitt circuit standalone, so I never built it. When I went parallel, I was unable to reliably share the triggers between the stock pcm and uS. Since I had the vishnu trigger kit sitting in a box, I went ahead and installed it.

The big question is why do you want to run parallel?

 

Everybody keeps asking me, "why do you want to run parallel." When I ran MS-1 with the CAS, it was very simple and it seemed bug free, but it also was inaccurate and sloppy. The MS-2 is very smooth, but now there are flaws. I want what I had before without the sloppyness. In a parallel setup, why did you share the triggers with the stock ECU?

 

The parallel installation is an attempt to pass OBD plug in emissions. I would not recommend it otherwise.

If this is not a concern to you, by all means, pull the stock computer out. It's just easier that way. Seriously, after the performance stuff, what's left for the stock comptuer to control anyway? Cooling fans and idle valve? Big freakin' whoop.

 

All I want to know is, can it be done this way. OBD-II testing is a concern here. All I want to know is can I cut the CMP and CKP signals from the stock ECU and give them to the MS and not have any issues?

 

It will trigger CKP and CMP MILs. The tach won't work. Have to run tach off the MS. The stock computer of course also wouldn't be able to run the idle valve.
I don't know what triggers the fuel pump. That might cut out as well.

Lots of pitfalls for no gain.

**something I have not looked into. It might be possible to install a 96/97 PCM and trigger it off a NA CAS. Would take at minimum some wiring, but it might proove to be relatively easy. The older the PCM, the dumber, so the easier to fool...

 

you should be able to diode isolate the crank and cam signals for each ECU.

 

I understand, in other words, there is no reason except to have a big pain in the *** if I want to run parallel in this manner. This is why there needs to be a MSPNP for '99 on up. I guess I am just back to troubleshooting Abe's PNP board.
Thanks for your help anyway.

 

I just missed that, but that's what I was thinking. I should be able to get the signal to the MS, while still providing the tach for the stock ECU, right? Back to the original question: Would this be possible and would it work sensibly?

 

I also have MS-1 + NA CAS retrofit. Someday I hope to upgrade to MS-II for smoothness of stock sensors. But the emissions aspect is very important to me, so it'll have to be parallel. I might be better off modding the trigger wheel to work on MS-1. Abe sent me instructions, but it's WAAAAAAAAY over my head.

 

Try it. Come to think of it, I think someone is running the Jason C/Joe P Schmitt trigger circuit (that Abe's board uses) in parallel on an NB. You'd need to remove the (2) pullup resistors.

 

Yeah Zaphod is running it that way I'm pretty sure. Here is his schematic:
wiring_nb1.6_ms_2.pdf

 

I basically want to run it exactly how he is running it. The only problem is, he lives in the Netherlands and not Pennsylvania, so I can't be like "yo dude, how about I buy you a case of beer and you let me take the cover off your MS and take some pictures". If you look at the diagram, he is sharing the CKP and CMP signals with the stock ECU. The IAT comes from a GM IAT sensor and goes directly to the MS. CLT, TPS, and GND gets shared with the stock ECU, and the Injectors and the Coils get cut and are driven by the MS only.
I have the harness, I have the MS-2, and I have AbeFM's PNP board. I want to eliminate the board and switch to the exact parallel unit of this schematic. Who can help me out here?

 

The adaptronic schematic calls out a Schottky barrier diode with the pointy side of the triangle going to the crank signal and the wide side of the triangle to the aftermarket ECU.

They leave the sensor connected to the stock ECU and splice in the Adaptronic.

Stock ECU/CKP -------|<-----Adaptronic

This guy is what I used:
Digi-Key - 568-1617-1-ND (Manufacturer - BAT85,113)

 

Here's a crazy idea. What would happen if I took my PNP board and soldered 4 wires to it in the OEM connector side, 12v, Gnd, CMP, CKP. Then on the DB37 side, I soldered 2 wires, CMP, CKP. The I spliced this in line with my parallel harness. Would the car fire this way? Would I have a tach on the dash? What would happen????

 

Sorry been away and I missed this completely.

Whats going on? Did it just suddenly stop working? My MSII has been running great, minus the idle, but I havent even had time to tinker with the stupid idle that I just left it.

 

Yeah mine ran great too, the idle thing didn't even bother me at all. What happened was I drove the car to work one night, and when I came out all it did was crank and crank. I towed it home and found out that the was no power going to the MS. I tested the 12v and gnd reference at the screw terminals and I only got like 6.4 volts. I pulled the PNP board out of the exclosure and I found that solder broke on my alternator wire. That was as far as I got, I just was fed up with constantly plugging it in and taking it out.

 

I'm resurrecting this from the beyond! For background, please see my build thread: https://www.miataturbo.net/megasquir...thread-102357/

I'm having issues sharing the CKP/CMP input signals with the stock ECU in my '99 parallel install and am looking for answers!!

Please tell me more about this. What is the purpose of this? Is it to prevent the ms2 conditioning circuits from creating noise in the stock ECU trigger circuits?

What is the purpose of this trigger circuit add-on board? I searched for the main thread on this but did not find any background, only how to build this circuit (all the picture links are broken now anyways). Ben you seem like you know quite a bit about these parallel implementations, could you read my build thread linked about and offer some advice?