thirdgen

iTrader: (26)

So as the signature says, I was running MS-1 in parallel on my '99. I recently removed this because I was tired of having some issues that I could not seem to overcome such as, the annoying "pop" when turning the ignition on, and simply the fact that I had to do a CAS conversion, there are a few other issues...
I see that some of you guys are running ALL the '99 sensors with an MS-II. Is it possible to take the MS-1 out of my current case, modify my current parallel harness, but convert to MS-II and eliminate this igniton turn on pop and everything else associated with MS-1?
What would I need to read / buy?
I need your input guys. I am running the stock ECU with stock injectors right now, and this means NO BOOST. It sucks, but so does a car that doesn't run right.
Thanks

Joe Perez

iTrader: (8)

Yes.

If you want, you can update your current 3.0 PCA to support an MS2 processor. There are just a few wires that need to be moved, and pullups added where they are currently missing. OTOH, I hate doing this sort of thing, and if you can spare the extra cash it'll likely be easier to start fresh.

The harness will likewise require only minimal modification. All you'll need to do are connect the couple of things that are not connected presently, plus move the trigger lines over to the OEM wires.

As to the ignition pop, the writeup I did applies to both MS1 and MS2, since they use the same spark output scheme.

thirdgen

iTrader: (26)

So basically your saying that MS-II also does the same pop as MS-1 due to having the same spark output scheme? You wouldn't by any chance have a wire diagram I can base my parallel harness conversion off of, would you? Does the MS-II get easy thermed just like the MS-1? I have no experience with MS-II, so turn my stupidy into a positive learning tool.

Joe Perez

iTrader: (8)

The popping is not due to a flaw in the CPU, it's due to a stupid design in the spark output circuit.

The MS2 does not require EasyTherm. Instead, you load the firmware into the CPU without modifying it, and then within MegaTune there is a window where you can calibrate the temp sensors while the MS is up and running.

As to a wiring diagram, I'd need to have the diagram for your current MS and harness first, since the location of internal mods relative to the DB-37 connector is at the discretion of the builder.

DMRider_10

The pop seriously bothers you that much?

Matt Cramer

MS2s are less prone to popping - they set the spark output much faster so there's a much quicker pulse, not enough to charge the coils.

thirdgen

iTrader: (26)

Yeah, it does. It's enough to sometimes blow off a vacuum line.

thirdgen

iTrader: (26)

So my MS was built to the specs on here:
https://www.miataturbo.net/forum/t13676/
My parallel harness has these wires:
1) 12v (MS DB28)
2) IAT (MS DB20)
3) Knock (not currently hooked to anything)
4) Gnd
5) Coil 2 (MS DB36)
6) Injs 2&4 (MS DB32-33)
7) CLT (MS DB21)
8) Gnd
9) TPS (MS DB22)
10) Coil 1 (MS DB31)
11) Injs 1&3 (MS DB 34&35)
LC-1 Yellow wire is on DB23 on the MS

I guess I am finally going to assemble this myself, but can somebody point me in the direction of what to buy / what to read on converting my MS-1 for use with CAS to MS-2 for use with stock '99 crank trigger? I also want to set up launch and EBC. I have the MS out of my car and dismantled on my kitchen table, so I am ready to get this project going like right now.