MegaSquirt MSII PCB v3 for 1988 Ford Ranger 2.9L

I've started building a MegaSquirt MSII PCB v3 for my 1988 Ford Ranger 2.9L. Already assembled the MegaSquirt EEC-IV adapter board. Using a JimStim 1.5 to test the new ECU as I build it.

Starting this thread to document the installation and I'm sure I'll have lots of questions.

During assembly I got to step 22, which is only followed if using an IAC, which is what my truck uses. Looks like newer trucks use EDIS. Can anyone tell me the pros and cons of IAC vs. EDIS-6? Is their improved performance or fuel efficiency with EDIS? Is it possible or worth converting to EDIS?

Huh? EDIS requires a wheel that you don't have (35 teeth every ten degrees w/one missing) and a pickup to even consider that option.

Don't think it makes much difference either way, besides which you need the distributor to drive the oil pump. If you absolutely want to go edis you can attach a toothed wheel to the back of your crank pulley (toothed wheels of various sizes can be found on your kids bicycle) and then a simple bracket to hold a pickup from a 4 liter, I doubt it's worth the trouble in this case.

What does it do?

I agree at this stage their is no point to EDIS (neat system thou) just let MS know you have an electronic distributor and make MS doing the timing.

The IAC is the cold/fast idle doohicky.

stegomon said:

What does it do?

Click to expand...

It will let me tune my engine using my laptop for fuel economy or power and hopefully will be easy to switch between multi-fuel and dual-fuel, like CNG and gasoline. Also could add a wideband O2 sensor and get even better economy running in closed loop.

There are lots of things it can do that I won't explore with it... like nitrous and boost control.

It does look like I could install a missing tooth wheel and a hall sensor rather easily to use with the Megasquirt.

Here's the MegaManual. Click on the MegaSquirt-II Introduction link on the left menu bar for full list of features.

Status update on the MegaSquirt.
Got to step 50 of assembly and have another choice to make.

50. Next you need to make a decision. There are two input circuits for the tach signal:
• The Hall/optical/etc. circuit takes the square wave input from a Hall sensor, optical sensor, or points. It can also be used for triggering off the coil (but only if you are not controlling ignition timing).
• The VR circuit takes the AC signal from a variable reluctor sensor and converts it to a square wave for use by MegaSquirt.

Fortunately there is a chart that says Ford TFI and Ford EDIS use hall/optical/etc, but then there is another choice:
a: To install the Hall/optical input circuit (or points without a coil connection)
b: For triggering off the coil negative terminal/points

If I was just guessing I'd say TFI goes with option B and EDIS uses option A. Since EDIS uses a toothed wheel/hall sensor and TFI uses an Thick Film Ignition coil and distributor, but since they both have ignition coils... arrrr... It would be nice if someone was holding my hand on this. Going to just have to be confident with my intuition and go with option B. I'm assuming "triggering off the coil negative terminals/points" means the points in the distributor that the rotor short circuits to ground.

Even after reading
http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml
I'm unclear again, because it is about the TFI system and talks about using a Hall Effect sensor in the CMP (camshart position sensor). So not a physical rotor making short circuits, but a rotor with a hall effect sensor similar to a toothed wheel, but using a metal block to create a signal that the PCM (assuming = ECU) then considers among other factors to send the spark to the TFI ignition coil.

So the question is triggering points without a coil connection or triggering points off the coil negative terminal. So what is a point? The key to understanding my truck is in this sentence, I'm pretty sure, [ECU] returns a reference signal to tell the TFI module to switch the coil. Since my truck uses a coil then can I assume the points are triggered of the coil negative terminal since the other option is triggering points without a coil and I have a coil?

"The CMP sensor, housed inside the distributor, responds to a rotating metallic shutter mounted on the distributor shaft. This rotating shutter produces a digital Profile Ignition Pick-up (PIP) signal, which is used by the PCM and TFI to provide base timing information, determine engine speed (rpm) and crankshaft position. The distributor shaft rotates at one-half crankshaft speed, therefore the shutter rotates once for every two crankshaft revolutions."

This describes my truck "The second [TFI] configuration is known as a remote mount system, since the TFI is mounted on the engine or front fender apron. The distributor used by this system is sealed and houses the CMP sensor. The distributor does not utilize vacuum or centrifugal advance mechanisms; the ignition timing is automatically controlled by the Powertrain Control Module (PCM) and the TFI.

Ford calls this electronic ignition the Thick Film Integrated-IV (TFI-IV) ignition system. The TFI module is also known as the Ignition Control Module (ICM) which reports engine position and rpm to the PCM. The PCM then determines the proper spark timing and advance, and returns a reference signal to tell the TFI module to switch the coil, thereby by creating a spark. The PCM used on these vehicles is referred to by Ford as the Electronic Engine Control-IV (EEC-IV) module."

I'm overwhelmed now. My intuition has changed between option A and B too many times.
A: To install the Hall/optical input circuit (or points without a coil connection)
B: For triggering off the coil negative terminal/points

Best to step away from it and sleep on it or wait for replies.

Cheers!

PS. I'm sure this is painfully obvious to some or even maybe most people. Forgive my ignorance please. This is all very new to me. Except for soldering components on a board... that's the easy part!