There is a MegaSquirt article in the latest (Aug09) Grass Roots Motorsports magazine.

Haven't read it yet, but it details adding it to a RX-7.

That's probably worth a read...

Good O2 sensor info Rob!

It's important to also point out that a narrow band O2 sensor has an EXTREMELY non-linear voltage output, where as the wide band O2 sensor out is linear. Here are some graphs:

Possible source for inexpensive wide band O2 systems...

Edit: A better smaller unit from the same site...

http://www.14point7.com/Widebands/NAW_OEM/NAW_OEM.htm

Where'd everybody go?

Let's get down to it. There's been some great discussion, but I'd like to get back to the original question. There were a few direct answers but not many really complete ones.

If I use the factory D-Jet setup for a 2.0 excluding the MPS,TPS and ECU, what do I need? Also going to be using a Mallory and MSD. Which components of the stock D-Jet will I not need? Some of you that have BTDT that could completely list what you're using would be killer. Wiring harness solutions would be cool too. And who's really using an MS without an O2 sensor?

From the stock D-jet system, you will need:

Injectors
CHT sensor
IAT Sensor

And of course, throttle body, plenum, runners etc.

basically everything except the TPS,MPS and ECU, right?

what TPS should go with the MS? we heard reasons the stock one wouldn't work, but I didn't get a model number or anything for what TPS to get

Gint -

Here's what I did. I hope I didn't forget anything.

- Stock 2.0L D-jet System as a starting point
- Added MS V2.2 with MSII brain (V2.2 is obsolete now)
- Ditched the 2.0L injectors and used 1.7L instead
- Added 4 injector series resistors (8 ohm I think) since I'm not using flyback mode in the spirit of KISS.
- Replaced TPS with a variable resistor type.
- Got rid of MPS, CSV, thermotime switch, D-jet ECU.
- Kept the AAR, FPR, stock fuel pump, and all the mechanical stuff like throttle body etc.
- I think I'm using a 1.7L CHT, you could probably make any CHT work. Using stock IAT.
- Added MSD and Mallory Unilite for ignition and tach signal to MS.
- Replaced tach guts with late model tach so it will accept the MSD tach output.
- Added Tech Edge WBO2 controller and Bosch 7057 sensor.
- Added bung to exhaust at the 180 deg. bend before the muffler (Bursch style setup).
- Built custom wiring harness based on stock D-jet harness.
- Made custom box to hold the ECU, wideband controller, inj. resistors, fuses. Box is mounted inside the car, between the seats.

Does this give you a better picture?

Well,

I'll take a whack at it from memory. I'll probably leave some stuff out and I'm sure there is more than one way to do this so, I hope others will pipe in.

Choices:

1) Use resistors (that is what was used on the 1.8l) or;
2) Use pulse width modulation to limit current to the injectors (kind of like turning a light on and off real fast, 1 more thing to tune)
3) How to trigger (you want to use MSD and that is good cause it has a nice clean signal)

Things you'll need:

1) Laptop or Palm device for tuning
2) Serial Adapter for tuning with laptop
2) Wide band O2 for tuning
3) Digital Volt Meter to test
4) Stimulator for testing unless you can borrow one.
5) Relay Board. This not absolutely necessary but, it helps a lot.
6) Soldering iron if you do a kit
7) Time

Fuel Delivery

From the tank, through the fuel circuit assuming you have carbs.

1) Tank sock
2) Supply hard lines through the center tunnel.
3) Fuel filter
4) FI fuel pump (stock or after market). I used the stock one for years and it was fine up through 2270. I am now using a Walbro in line pump. This can be mounted up front.
5) Fuel injection hose to the passenger fuel rail (stock is fine). clamped with FI hose clamps (Use these on all of the high pressure hose).
6) Passenger fuel rail 022 133 321b
7) Injector #3 (Stock 2.0l, 1.8l or 1.7 liter !.8l injectors will accept more modern Bosch style connectors, big plus)
8) Injector #4
9) High pressure hose from the passenger side to the drivers side
10) Driver's side fuel rail 022 133 315b
11) Injector #2
12) If the rail has it you can attach a fuel pressure gauge to the bung on this rail between injectors #2 and 1.
13) Injector #1
14) High pressure hose
15) Fuel pressure regulator (Stock works pretty darn well) 039 133 551
16) High pressure hose to the return line to the tank.

Air Delivery

I used a lot of the stock 2.0l stuff. I'm not familiar with the 1.8, 1.7, or bus.

1) Stock air box 039 129 607a
2) Stock Air filter 039 129 620a
3) Stock 45 mm throttle body 039 133 063d
4) Stock plenum 039 133 055b
5) Stock hoses to connect runners to plenum 039 133 241
6) Stock intake runners and manifolds 039 133 201b
7) Stock intake manifold gaskets 039 129 707

Electrical

Megasquirt stuff

1) MS 1 kit
or
1) MS 2 kit
2) Above mentioned relay board if you want
3) Cable from relay board to ECU or this can be made.
4) Harness from relay board to engine and sensors. You gotta make this I think.
or
2) eliminate the relay board and use DIY Autotune's harness. This looks pretty cool and wasn't available when I did mine. You would need fusing and a relay for main power and fused and relay for the fuel pump and idle air control if you use that. And, fusing for the injectors.

Power

1) Switched 12V. I got it from the hot wire to the coil, 12pin connector, pin 7 on the car's relay board.
2) Good ground I took it back ti - side of the battery.
3) 12 V from the battery to supply the relays
4) Good plug wires to keep electrical noise down and resistor plugs seemed to help.
5) Shielding on the tach input for triggering MS

Sensors

1) Map sensor is on the MS board. You need to run vacuum to this from the plenum to the port. It may need metering to sooth out the signal such as a filter in the line or I use a MIG welding orifice.
2) Intake air temperature, I used the stock one in the plenum. It is subject to heat soak and needs to be calibrated with a program from Megatune
3) Engine Temperature sensor. I used the stock cylinder head temperature sensor by #3 spark plug. It needs to be calibrated with Megatune.
4) Throttle position sensor. I went to the junkyard and found one that worked. It needs to turn the proper direction and have the proper shaft size. It was not easy to find. SDS sell them and you could try there. I'm not sure about the shaft size however. This needs to be calibrated.
5) O2 sensor. Many to choose from. I use Techedge and I like it a lot.
6) Bung for the O2 sensor
7) Trigger. You mentioned MSD and that has a nice output that will trigger the injection events. I can't remember which circuit you would use in MS however.

Vacuum stuff

1) MAP signal from the plenum to the MAP sensor on the MS board. As I said above it may need to be quieted.
2) Idle air. The simplest way to do this is the stock system with a auxiliary air valve 022 906 045 with switched 12V from the fuel pump circuit and vacuum line from the air cleaner to the plenum. MS1 can control an idle air valve and MS2 can control a stepper motor for idle air control.
3) Stock crankcase ventilation
4) Stock charcoal cannister for fumes.

Dave

For the TPS, almost anything will work. I found one from a volvo, on ebay. The hardest part is getting one which matches up with the D shaft on the throttle body. I just looked at the pictures of the TPS on ebay, until I found one that would take a d shaped shaft. Not too hard in the end.

TPS must accept the D-shaft, as well as turning the correct direction. Some turn clockwise, some counterclockwise.

Mine is from a group buy on the MS forums several years ago. If I find a source for more I'll post the details here.

Yes it does. Thanks to you Jeff and everyone else that has contributed to this thread.


DIYtune's site says that the 'MegaSquirt-I Programmable EFI System PCB3.0' can "Use any injector - High or Low impedance."

Is this the flyback mode?

Your memory is obviously better than mine Dave. Amazing! Thanks.

Actually it doesnt really matter which way it goes.. If it goes the wrong way, then you swap the wires around.

To the guys who have done this before,,,

I bet it would help if we can get the part #/car info of the TPS that fit the stock throttle's D-shaft. I would bet there are some OEM ones that should fit right on the shaft, and would only need an adapter plate fabbed up.

-Rob

TPS - 1336385
Volvo Applications:
C70 '98'
S70 '98'
S70 Turbo '98'
S90 '97 thru '98
V70 Turbo '98' X-Country
V70 '98'
V70 Turbo '98'
V70 T5 '98'
V70R Turbo '98' AWD
V90 '97 thru '98
850 '93 thru '97
850 Turbo '94 thru '97
960 '92 thru '97

Jeff, See post #163 please.

I think MS 3.0 includes all of the flyback circuitry onboard (some of it may be optional) as opposed to 2.2 which required a 2nd board for flyback.

V3.0 supports both high and low impedance injectors because you can either add series resistors to low impedance injectors (like I did) or use PWM mode on the injector drivers to limit the current.

Both approaches have advantages and disadvantages, the biggest disadvantage to PWM mode (imho) is that if for some reason the settings get screwed up you can fry your injectors with too much current.

The disadvantages of injector resistors are slow open/close times limiting the minimum duty cycle and problems getting the injectors to open during cranking. I haven't experienced either of these problems with my setup. YMMV.

Hmmm... definitely food for thought there.

So that's 1 8 ohm resistor in series for each injector? In the harness I assume?

I mounted them in the ECU box that I stuck between the seats inside the car. The resistors go in series with the MS injector outputs, so it made sense to mount them next to the MS. I'm pretty sure they are 8 ohm, 10 Watt resistors, just because that is what I found at the local electronics store. I think anything from 6-10 Ohms should be fine.

The pic below shows the resistors in the box before the ECU and WBO2 controller were installed.

Nice. With pics even! Thanks.

I'm uploading a bunch more as we speak:

http://www.flickr.com/photos/mightyohm/set...57619942677458/

Click to view attachment

all you need, included is a relay box and a harness made from beck arnley connectors....not included is the wide band O2 controller....

use a tps with a d shaft..around36 to 40 bucks from someone on the internet...

Wow. I like the way you did that. Very nice work Jeff. Did you test run all of that before you built the assembly? Just curious... The ferrite ring on the red wires into the fuse block; looks like main power for the whole shootin match?

THANKS

-Rob

I tested the Megasquirt on the stim and had the WBO2 in the car for a few months before I switched over. I checked that all of the sensors were working before firing it up the first time, but everything pretty much just worked.

If you dont want to spring for the relay board, it is quite easy to use the stock relay board on the 914. I used the old ecu connector that attached to the stock board. This saves having to wire the fuel pump etc.

This is how I did it. I'll find my wiring diagram, but I used a couple of wires from the four pin connector to power the MSII, EDIS, and LC-1, and the fuel pump goes through... I can't remember, but I'll dig it out!

This is fantastic! Thanks to all and keep 'em coming.

I used the stock 914 relay board also. I am still using the stock fuel pump relay and D-jet power relay with the MS.

That's what I'm planning on doing. I need to find the fuel pump wires at the harness though. PO cut them off or something when they did the carb swap.

FYI: The fuel pump wires are in the body harness (not the engine harness) and branch off near the battery tray.

I know. They're still MIA. Some DAPO cut them off or something

I got motivated to go out and look for 'em. They're there, but as I guessed they've been cut off right where they come out of the harness sheathing.

Strip, solder, heatshrink.

Ok slackers... I gave you the weekend off. Thread almost fell to page 3.

Anybody know where that really good pic of a relay board is? In particular the one "with circles and arrows and a paragraph on the back of each one explaining what each one was"? (Thanks Arlo).

This is a good one...
http://www.914world.com/bbs2/index.php?sho...hl=relay++board

What about late 240 series and even early 700 series cars? I saw a boatload of them in the pull-n-save today.

No idea. Sorry. It took me a bit of searching to just find that one.

Hi Mark, folks,

following the discussions concerning cheap aftermarket efi systems i'd like to say some words about
my experience with megasquirt on a 2l fourbanger.
Right now I'm running a MS-1 systems since three years without any problems. I build my system
completely from scratch using a PCB for the MINI-MS which is a MS1 derivate. I've integrated the
PCB into an old L-Jetronic case from a 1987 320i BMW. The nice things about this combination is,
that i don't need the megasquirt relay board, since the pcb has the relays onboard and the pretty nice
connectors of the L-Jetronic system which i've used for the wiring harness. As you can see in the
pictures i've also integrated the load resistors for the original injection (green) valves into the same
case. I've experienced no problems with heat dissipation or any other kind of problems with this
setup.
The MAP sensor is build into an old Bosch D-Jet MAP sensor housing which give a pretty stock look.
The original TPS is modified with an aftermarket resistor build by spectrol bought from the electronic
distributor farnell here in germany.
Except the TPS, MAP sensor and a pertronix ignition all other parts are stock D-Jet system parts
(intake temperature sensor, auxiliary air regulator).

It's absolutely important that you use a wideband o2 sensor. Without that you will never be able to
tune your system. I've used the innovate LC-1 system for tuning which I removed after approx. three
month of tuning and tinkering with the various options megasquirt offers you.

If you have some experience with electronic stuff (I'm an EE) I can only say - go for it !! The car runs
like a charm and you can remove all the 30 years old crap from your engine compartment, which is
no more needed for your new EFI e.g. old throttle switch or those crappy triggering contacts in the
distributor ...

Just another hint: Do yourself (and your car) a favor and build a new wiring harness! The most
problems with efi swaps arise from old broken wires reused for the MS system.

greetings form Berlin/Germany

Benno

Very nice craftsmanship Benno. It looks perfect.

Got me a wideband O2 and controller! For reference:
http://www.914world.com/bbs2/index.php?showtopic=96974&

Benno, nice job on that L-jet case! Reusing the connector is a brilliant idea.

The TPS sensor you used is exactly the same as the one I'm using on my car.

For my MSII setup, I used pin I of the Four Pin Connector to power the MSII, EDIS module and the LC-1 Wideband Controller, with inline fuses for each of those.

Pin III is the fuel pump relay ground, and connects to pin 37 on the MSII's DB37 connector.

My harness is wired the same way.

Some Reference Info.....

There are 3 basic types of fuel injection....

1. Mass Air flow systems.
Think L-Jet.. Load is determined by amount of air coming into the engine.
2. Speed Density Systems
Think D-Jet..Load is determined by throttle position and and manifold vacuum.
3. Alpha-N systems.
This is MFI. Load is determined by engine speed and throttle position.



Gint... You could go with Mechanical Fuel Injection. Just find the injection pump of a BMW 2002 Tii. It would be cool.... (Yea, I know, don't bug me... I like MFI).


15 years ago or so, I built a modern fuel injection for a 914 out of the injection for a Oldsmobile Quad 4 engine. I used the GM DIS and the Mass Airflow injection. I also used the throttle body from the Quad 4. It was a great system. I took the intake plenum from a 2.0L 914 and cut out the throttle body mount, then welded in a plate with the proper bolt pattern for the quad 4 throttle body. I machined the flywheel to have the notches for the DIS in the back, and mounted the crank sensor in the hole in the back of the case that opens to the flywheel (the one for the VW automatic stick shift torque converter bolts). I put the wiring harness together and used the stock relay board as much as I could.

It ran really good, but I constantly had a check engine light as I never found the part I was looking for to fix the vehicle speed sensor. Then the starter hung and chewed up the teeth on the flywheel, so I had to replace it. Pulled the whole system and went back to carbs due to a lack of money to get a new flywheel machined.

Still have most of the parts. I cut the harness I built to get it out when I decided to do the six conversion.

Gint,

check this link from shoptalkforum, more info than you will ever need for different FI systems and other suggestions:

http://www.shoptalkforums.com/viewtopic.php?t=114309

however, this made add to your confusion.