engine and drivetrain Required inputs for EFI?

[robsanab]

I was told by the MS tuner who I plan to hire to help with my EFI conversion (with the 318i set-up) that I need the following inputs (I am not familiar with all the lingo, but he’s talking about the greatest and latest Megasquirt software):

1) Vacuum sensor

2) Intake air temp

3) Water temp (318i water inlet)

4) O2 sensor (bung on downpipe)

5) TPS (jeep stepper motor)

6) RPM (will use hall sensor on crank)

1st question, I am gathering all my parts and I’m unsure about where #1 and #2 come from? Not seeing these discussed in previous posts. What are the drawbacks if I don’t have these inputs? He seemed to indicate that the above inputs were the minimum.

2nd question… I’m also a little fuzzy on what is required spark wise… I am wanting to go with the coil on plug LS1/LS2 Yukon coil setup that others have done. Will the 36:1 trigger wheel/hall sensor work for this now that MS has outputs to drive coil per cylinder?

If not, is the next best option to go wasted spark with a coil pack? I have a Crane XR700 but don’t mind going another route in order to eliminate the distributor or other parts that could go bad.

This is for a reliable daily driver with mild engine, so I know the individual coils are overkill, still from the discussion here it seems to be worth it due to all the available advance, plus I don’t mind spending a little more if there are other benefits such as eliminating ignition modules or such.

[ifayeoh]

Goto 02again.com and click on link for presentations, alot of stuff to read up on, have fun and post results,

Frank

[Chamonix72]

You can buy all the needed sensors, etc, directly from www.diyautotune.com There are also many links with tons of information. Almost too much. As mentioned above, Tom at 02 Again has some good information on his site. I'd also ask the guy who is installing the system what he wants. That's what I did. I got a shopping list and got to work.

[robsanab]

Goto 02again.com and click on link for presentations, alot of stuff to read up on, have fun and post results,

Frank

I have read up on things (not that I understand it all, but I’m trying to, hence these questions). As I said that is why I am questioning these two inputs that my MS guy mentioned because I haven’t read about them. Is no one else using them? Is there a way to provide them if it would help the computer?

[robsanab]

I'd also ask the guy who is installing the system what he wants. That's what I did. I got a shopping list and got to work.

I did ask the MS tuner guy and this was the list he gave me, hence the questions on two items I’m unsure about since I don’t see them mentioned anywhere.

I have read, I am trying to understand what I read by asking questions. Additionally, this Tuner is not totally familiar with this application or what’s available sensor wise for our cars... why am asking here.

How about giving me your list!?!?! I have that fine post from slash02 from early last year with a great summary of parts and pieces... but as I said these were a couple questions that still linger for me.

[Chamonix72]

I believe you do need some sort of MAP (manifold absolute pressure) sensor. There are several types available from DIY Autotune, including one with a barometric compensator. That signal, combined with the engine speed and intake air temperature to calculate the speed-density. For reference, here is what I purchased from DIY Autotune:

MS II ECU

Relay Board

MAP Daddy 4

MS Wiring Harness

Relay Cable

IAT sensor, with pigtail

CLT sensor, with pigtail

Injector pigtails

I purchased all the other stuff from 02 Again.

[Zorac]

isnt there a map sensor onboard with megasquirt? all you have to do is run a vaccume line from the megasquirt box to the intake manafold?

[allbim]

isnt there a map sensor onboard with megasquirt? all you have to do is run a vaccume line from the megasquirt box to the intake manafold?

Yes there is.

[robsanab]

isnt there a map sensor onboard with megasquirt? all you have to do is run a vaccume line from the megasquirt box to the intake manafold?

Yes there is.

now this is getting convoluted... are you guys answering the question about my item #1 vacuum sensor? which i assume is the reading for the MAP? If so, does that mean I just take a vacuum hose from the manifold straight to the MS box since the latest MS version comes equipped? Don't need the MAP Daddy kit mentioned above?

[robsanab]

oh and a clarification on item #2 the air temp sensor... I know one is required but I am unsure of what it is... where it's located?

[slash02]

oh and a clarification on item #2 the air temp sensor... I know one is required but I am unsure of what it is... where it's located?

you need to add one, I ran one just loose in the engine bay, but have relocated it to just behind my cone filter.

[Chamonix72]

oh and a clarification on item #2 the air temp sensor... I know one is required but I am unsure of what it is... where it's located?

If you are using the stock 325i air intake hose, there's a spot for one there. Or, in whatever piece of tubing you're using for an intake supply. Theoretically, it should be fairly close to the throttle body so it's reading a temperature that is the closest to that of the air entering the TB.

[AustrianVespaGuy]

Goto 02again.com and click on link for presentations, alot of stuff to read up on, have fun and post results

+1 for Frank's recommendation of 02again.com.

Of the needed sensors, the wideband O2 is the most important, expensive, and most involved installation, so be sure and spend some quality time on that part. As far as ignition, I personally run and highly recommend the Ford EDIS wasted spark setup. I think the early 90s For Escort has the right coil packs, plug wires, and EDIS box. Fairly stright forward installation, works fantastically, and 02again has the perfect crank pully w/trigger wheel and mounting bracket for it! I've done a lot of Megasquirting, so feel free to email me if you have more questions as you go along.

-Carl

[JHG762002]

1. As mentioned the MS board has a vacuum sensor on it to monitor manifold pressure. You will need to run some vacuum tubing from the manifold to the MS computer. The 318i manifold I used had two small ports (not sure what else to call them, nipples?), one I used to provide vacuum for the fuel regulator and the other for the computer. I don't recall exactly which brand of sensor I used for the air temp, but I also located it downstream of the filter in the intake pipe. It's been a while since I did the install but I seem to remember not putting it in the plenum because I wanted to avoid heat soaking the sensor. The MS forum is pretty helpful if you haven't looked over there yet. I haven't been to diy auto tune in a while but they have all the sensors and connectors you will need.

2. I am running EDIS, but I am pretty sure the newer version of MS can drive the coils you want to use. I would go that route if I were starting fresh. The crank pulley and wheel from 02 again is very well made and probably a lot less than what you will spend at a machine shop having something hobbled together.

[jimk]

No 5) A TPS is a Throttle Position Sensor and measures the throttle shaft rotation. The Jeep stepper motor is for idle speed control and is an air valve that bypasses the throttle plates. Two different items.

Inlet air temperature is not absolutely necessary. Air temperature corrections are based on degK (Kelvin) and don't have over 2% correction unless you live in Nome, Alaska. It's one that the purists think is necessary and have their fuel maps off by more than what the air correction is. Put one on if you think you neede it.

Most items can be picked up cheaply at a salvage yard alon with their electrical connector and pigtails from GM vehicles. The jeep stepper motor is only something with different screw mounting holes that O2again makes an adapter for. If you get and use a Jeep throttle body, it has one built in. Nothing magic about BMW parts on this.