So I am 100% positive I'm goin MS ever since I read that there are guys running MS with stock sensors. Here's what I want to do. I got a boomslang harness to run my MS in parallel with my current computer. The wires are as follows
1- 12V
2- IAT
3- Knock
4- Gnd
5- Coil 2
6- Injs 2&4
7- CLT
8- Gnd
9- TPS
10- Coil 1
11- Injs 1&3

I am thinking an assembled MS II with a PCB 3.0 from DIY Autotune. What mods will I have to do to this to make it work with my setup USING STOCK SENSORS. This will eliminate my MAF? Any suggestions are always helpful.

 

You'll have to build a couple input circuits to read the factory sensors. I've posted pics of mine here before. Search and you'll find them. Arga on the forum designed them. I copied them and they worked.

But I will say this. I already did this setup before and so have others. It sucks. (don't ask why, search for threads by me and others like AbeFM) Go standalone if you don't have to go parallel.

 

To make a stock 3.0 MS2 ready for NB parallel use:

1- remove pullup resistor R7 from CLT input circuit.

2- Build Abe's crank & cam input circuits, w/o pullups (stock ECU will be pulling up).

3- Build DIY's spark out mods, exactly as written.

So far as I'm aware, this will not, by itself, eliminate the MAF sensor. Even though it will no longer have an impact on spark or fueling, the stock ECU needs it in order to be happy. Some have experimented with building a circuit to spoof the MAF sensor signal to keep the ECU happy- I've not heard of anyone succeeding, but then I've not heard of anyone failing either.

 

I'm not concerned about elimating the MAF. All I want is to set up the MS II correctly, plug it in, start my car up, and tune it. I figure now is the time, enough people have done this similar setup and are running stock sensors, so now it's my turn.
Thanks guys!

 

I've been running MS2 in parallel (in various forms) for about a year and a half. I've been pretty happy but I think I've also been pretty lucky. I've seen little blips in the past that sound like what Pat described but I haven't felt a misfire in about 8 months. I like Abe's op-amp circuit a little better but I'll be happy to share what I have if you'd like.

BTW, I haven't modified anything in the last 8 months. During that time it's seen 14F to 124F and sea level up to 4000ft. I did have trouble w/ rolling idle at >120F but otherwise it's been perfect.

 

So I assume you built your MS II and didn't buy it as an assembled unit? What do you think would better benefit me? Buying it assembled and then modifying it, or building one? Would anyone be interested in making some money and building me one for this particular application?

 

There are some advantages to both ways. If you build it, you'll have that much more experience with the MegaSquirt and be able to say that I built my EMS.

If you buy it assembled, it'll save you some time so you'll be "squirting" that much quicker.

Since you are going to have to modify it anyways, I would recommend just getting a Kit and building it. If you have time for it that is, most first time builders take 8-10 hours, but these are the guys that haven't really done any PCB level soldering.

 

+1 on building it yourself. As far as I know, the circuit I'm running hasn't worked out for anyone else but it has been a starting point for a few people to build their own designs. Plus, my input circuit is dirt simple. It's just a transistor and two resisters per channel.

 

So I saw something about people using MS I with a parallel setup? What should I go with? This is the thing that confuses me most about MS...everybody does everything differently than everybody else. This guy uses MS I and has no problems...That guy over there uses MS II and has to F around with it and has some issues...the other guy down the street uses MSII but is happy with it....ya know. So what do I go with? I mean...if I buy a Hydra..I buy a Hydra and that's it, there aren't 57 different versions and ways to use a Hydra. So why isn't there 1 standardization of MS?

 

This is likely where Joe will jump in saying "there are several ways to skin a cat." (he has told me this before ) Some people are more comfortable with some things than others, think that certain things will be easier etc. Just go standalone like I am going and you will be ok. I started out building the stim and then built the msII 3.0 and finished a little while ago. Granted I am not electronically inclined and cant build those damn trigger inputs, or figure out that damn harness, but everyone on this site was extremely helpfull while I was building my ms. Its really easy to follow the instructions to build the MS though.

 

I'm in a similar boat here. I have the POS PowerCard in my 2000 with a JRSC. It dumps in so much uneeded fuel that may car has fried 5 O2 sensors and just 3 days ago now a 3rd Cat and the car only has 60k on it. I've decided to just get a properly running ECU to control Timing and fuel and everyone says MS2, yet the more I look the more wary I am. All I want is to buy a premade unit and a harness, hand it to Mike (at Mikes place) and have it installed and then have it flatbeded over to AZ Dyno Chip for tuning. I'm not interesting in ridiculous amounts of work. I'm a former ASE BMW tech and have done many aftermarket setups and never seen anything so ridiculously complicated in my life? I just want to buy it and have it installed. But I HAVE to go parallel as AZ emissions testing just pulls codes from the stock ECU through the OBD II port. No stand alone units will work for my situation.
So what is the deal here? Can I just buy what I want ready to install, or am I better just going with a Greddy EMU unit that is ready to go as is?