Hi all,

I'm looking at engine management for a future turbo installation. Before I moved to California, I had planned to install an MS-I with an NA CAS in parallel with the stock ECU. This was to give me OBD-II for emissions (set it and forget it).

I have all the parts, and the wiring in place, but I haven't installed the sensors or physically mounted the Megasquirt.

Now I'm in California, and have CARB issues to consider. I'm trying to decide how to approach engine management, given this new constraint.

Two of my options involve Megasquirt.

• Continue as planned with the MS-I
• Sell the MS-I and go with the newer MS-IIl technique

I'm also considering CARB EO legal options, or legal enough options, but for the purposes of this thread, assume I'll be switching back to stock on emissions days.

 

Get the MS-2. Due to better fueling precision of the MS-2 and the ability to be in closed-loop at idle, you will have far better chances of passing OBD and tail-pipe sniffer tests.

Dimitris

 

you need the MS-II in order to read your cam and crank sensors.

 

I believe I have all the parts for an MS-1 in a parallel install (such as a 1.8l NA CAS).

Is it worth it to sell this kit off and buy the shiny new stuff?

 

buy the ms-ii chip and run it parallel as well?

 

What kind of effort are we talking about? I bought my MS pre-assembled at DIYAutoTune. I imagine that going with the MS-II isn't as simple as swapping a chip.

Considering that I already have the MS-I setup, what would motivate me to go with the MS-II?

 

Its not exactly, but close. I think the only real difference is the input for the second trigger/cam signal. On MSI, its on JS8, but on MSII, its on JS10.

 

its a little more than that, but basically...

 

I'd probably sell this one and buy/build a replacement, as long as the cost wasn't outrageous.

That aside, it sounds like the advantages are AC & alternator control + the ability to read NB sensors.

Since I've got the NA CAS, and a parallel install takes care of AC & alternator, is there a strong reason to move to MS-II?

 

I've been reading all the NB MS-I and MS-II threads I could find, and this is my take.

MS-II:

• Ease of installation (reads stock sensors)
• "Smoothness" (more processing power?)
• The PNP kit from DIY provides idle/AC/alternator control

MS-I:

• Some report too much error when using an NA CAS. The alternative to the CAS is customized crank wheel. Sounds like a hassle.
• Needs custom circuits or a parallel installation for idle/AC/alternator

Some people (AbeFM) seem to really hate the NA CAS option. I've got the parts and was planning on going down this route.

How serious of an issue is it?

 

Incorrect. The DIYPNP can NOT provide the ~500Hz frequency with the required precision (you need the jbperf.com PWM board) for the idle valve, it does not properly and fully control the A/C (the A/C will not disengage when you go WOT or when RPM>5000) nor does it compensate for the A/C kicking in by addding more duty cycle to idle valve. Also, there is no alternator control on the board, you will have to create the circuit yourself from scratch.

Dimitris

 

I see. When I read the article, I assumed those mods were included.

In my case I'll likely install in parallel and let the stock ECU deal with all that.

 

While a parallel installation seems to work best, there are a few problems here and there. I had wild idle oscillations when I had the A/C activated during idle, or when I had major electrical loads also applied during idle (heated rear window and mirrors, heated seats, high beams, etc). I never managed to solve them while I was running in parallel.

Dimitris