Matt Cramer

Well, the trouble is that the distributor's signal is meant for a distributor type ignition. It just tells the ECU that a cylinder is ready to fire, but it doesn't tell the ECU which cylinder that is. Instead, the ECU triggers the coil and relies on the distributor to route the spark to the appropriate cylinder. Now, there are a few setups that use the Megasquirt to drive the coils in a distributorless ignition directly with no EDIS hardware at all, but again, they'd need a different trigger than what is in the stock distributor.

Is MegaTune showing a pulse width while cranking or not?

Could you post a data log? It may have gone into flood clear mode. That's the usual thing that will shut off the injectors during cranking. If it actually says no pulsewidth on MegaTune, that's an indication that the issue is that MegaSquirt is commanding the injectors not to turn on, rather than that there's some fault keeping them from turning on.

Megasquirt does not absolutely need 60 degrees or so of trigger advance; you can also set the trigger angle to 15 degrees or less and it will predict the next interval instead. That's how I'm running it on my Mopar slant six. But you can adjust the '83 turbo distributor far enough to give you 60 degrees of advance.

Gavin, When you tested rotating the distributor with the drill, did you have MegaTune hooked up? If so, what sort of RPM did you see? Also, what was MegaTune showing for ignition advance and dwell?

You need a 3/8" NPT tap - these are pipe threads, and they are not 3/8" in diameter at all (kind of hard to say what the 3/8" actually refers to, but it's probably close to the inside diameter of one kind of 3/8" pipe). The 3/8" NPT thread has 18 threads per inch, and the nominal outer diameter is 0.675". So be sure it's a pipe thread tap with the right number of threads per inches - there are some other pipe threads like BSPT where the 3/8" tap has 19 threads per inch.

We've got a complete write-up on what board mods you need on the article where that drawing came from: http://www.diyautotune.com/tech_articles/how_to_megasquirt_your_280zx_turbo.htm If you bought it preassembled from us, it should have all the input mods already done, unless it was a special order. The input mods are removing C12 and C30, jumpering D1, and removing R57. These mods are all there for triggering off a coil terminal, and our usual preassmbled units are not built that way.

Most of the documentation on that page is about setting up the fuel. There's a little bit of mention about optical pickups, but there actually isn't that much in the settings you need to deal with. You will need to set a trigger angle that lets you turn the distributor to a position that can give you full advance, just like in Moby's write-up. And I'd try setting the ignition input capture to Falling Edge. The VB921 output circuit looks like this: http://www.msextra.com/manuals/MS_Extra_Ignition_Hardware_Manual.htm#singlecoil22 Only you wire its input to pin 5 on the JP1 header instead of the LED's resistor, and omit the resistor.

The drawing you see there assumes the board is configured for the Hall sensor / optical trigger input (if you bought a preassembled board from us, that's how we set them up by default) and that you have included the spark output through VB921 mod. With the GM HEI module output, it depends on which pin you are trying to trigger it from.

That sensor needs a controller, too. Our cheapest option would be the LC-1, which can be ordered in a package with the sensor. A Stimulator board is also a very handy thing to have, and pretty much mandatory if you are building the Megasquirt yourself. Looks like you're on the right track with what you need.

Drew, With a V3 board, a Megasquirt won't actually need injector resistors. But they may be there anyway. Injector resistors are often physically fairly large; I've got a Toyota resistor pack that is about the size of a pack of cigarettes. A chassis ground wire under the plenum may simply be to help ground some of the sensors on the cylinder heads and/or intake manifold.

You got it. The V3.0 board is definitely a better choice for Supra injectors and spark control - I'm actually wrapping up an inline six project where I used Supra 440 cc/min injectors and spark control on a V2.2 board, and I had to put in a resistor pack (yanked it off a Toyota Cressida) to protect my flyback circuits and some wiring changes for the ignition. The V3.0 board can control those injectors without the resistors or the add-on flyback board, and has more provisions for ignition control.

Digikey does have a few that will work - search for power resistors. They don't have ones that are precisely 6 ohms, but they have some that are close. They're often easy to find in junkyards, too. I grabbed a resistor pack off a Toyota Cressida - it's about the size of a pack of cigarettes and has cooling fins on it.

Yeah, the MS-I can handle most installations. The only thing that absolutely requires an MS-II is controlling a stepper motor IAC - they're distinguished by their four wire connectors. In some cases an MS-II is easier to wire up, though. The Megasquirt uses a couple of external relays that are not included with the kit or an assembled unit, as they're not part of the ECU itself. These are there for supplying power to the ECU, controlling the fuel pump, etc. The relay board is a preassembled mounting point for the fuses, relays, and similar components, providing an easy way to wire up the Megasquirt for a car that does not already have the necessary relays and fuses. The relay board is designed so that you can mount it under the hood, and it connects to the Megasquirt with a single cable.

Later Fords ended up combining the ECU with the EDIS module; a 2003 Ranger would not have a separate module. I just searched on Alldata and it appears this disappeared sooner than I thought; 1994 may have been the last year for a separate EDIS module on the 4.0 V6.

Your best bet would be a '90 or later model with the 4.0. It has to be from a six cylinder - the number of cylidners is already programmed into the module and you can't adjust it. See this page for the details on EDIS: http://megasquirt.sourceforge.net/extra/edis-whatyouneed.html They go into a fair amount of detail about how to wire it up and tune it. Here are the wiring details, with pictures: http://megasquirt.sourceforge.net/extra/edis-hardware.html