Matt Cramer

Is this a '82-'83 Turbo distributor or something else?

Theoretically, you should be able to keep the same VE table and tuning. You would need to change the following: Required Fuel Battery voltage correction and injector opening time (maybe) Acceleration enrichment pulse width Cranking pulse width

Correct. It has a table of how much fuel to inject based on MAP sensor readings and RPM.

Could be a hardware or a configuration problem. Try taking the case lid off, turn the ignition key on, and check the voltage at pin 1 of the MAP sensor (the square hole on the 6 pin header). What voltage do you see with the engine off?

Normally, MegaSquirt will fire one pulse when the key is first turned on, to clear air from the fuel lines. Then it shuts off the injectors and waits until it gets an RPM signal until it starts up the injectors again. It also shuts off the fuel pump after 2 seconds if it sees no RPM. Are you seeing RPM in the tuning software when you crank the engine?

Ok, let me make sure I'm hearing you right on what is going wrong. You are (1) not having any injector pulse width, and (2) not seeing any RPM when the engine is cranking? In that case, you will need to fix (2) first; the MS "thinks" the engine is stopped, so it's not giving it any fuel. What exactly are you doing for ignition?

Yes - very few MegaSquirt users make use of the MAF; at most, it may be left in place to meet some racing sanctioning body's rules. The flapper type air flow meters pose a pretty huge restriction. Yes - you can either have the distributor controlling the spark advance and feed the MegaSquirt the tach signal off the 6AL, or have the MegaSquirt control the spark and tell the 6AL when to fire. The first approach is easier if you're just getting started out, but you'll probably want spark control by the time you go turbo.

Just checking - you aren't powering the EDIS module from the fuel pump relay, are you?

Dead EDIS modules aren't impossible, particularly if it's a used module. They don't have a very high failure rate, but sometimes a junkyard EDIS module could very well turn out to be the part that sent the car to the junkyard.

We haven't had a chance to test the sensor itself, but I suspect it would use the same pull up.

The writeup on our site works for the standard value (390 ohms) of R12.

We recently started carrying a high performance coil that's basically a Caravan coil with high output windings. Here's a pinout diagram I made for it.

It's best to wire all the sensor return wires together and run them to pin 19 (or one of the other ground wires).

The relay *board* does not have a flyback diode in place, but there is a flyback diode for the fuel pump relay on the main board. It's a somewhat different type as it uses a zener diode to pull a voltage spike to ground rather than running the voltage spike to the 12 volt plane.

The V3.0 flyback circuit is for the injectors. Using the diode is a good idea.

That diagram is somewhat generic. SPR1 does not go anywhere on the relay cable. You don't have to, and in many cases should not, use the same input and output sources. It's just one example!

Don't wire it to SPR1 - use one of the jumper pads meant for the MS2 IAC wires.

SPR1 = a pad on the main board that connects to DB37 pin 3. Standard relay cables don't use pin 3. S terminals - S1 through S5 on the relay board.

Looks like you've got it and yes you can use the relay you have. SPR1 doesn't come out on the relay board but you could use one of the four IAC terminals and pick up the signal at the corresponding S terminal on the board.

The distributor signal wire. To put this in a V3.0, run a 1K resistor from S12 to TachSelect.

Usually it would show zero volts: full lean. Check the voltage coming out of the sensor.

I haven't checked every wire, but overall it looks right. I would put the resistor inside the MS instead of in the external wiring but this is a matter of personal preference. One thing that doesn't look right - it seems like you have the fan relay on full time? It looks like it's wired to constant power (should be switched if MS is controlling it) and a permanent ground.

Nicely done. If the MS is controlling the coil, it will wait for a pulse from the distributor, but it can read that whether the coil has power or not.

Bogus readings for Duty Cycle 2 are a well known (but harmless) MegaTune bug. Does the O2 sensor input work correctly on a Stim?

That's the sensor return trace that's fried. It looks like you either wired a 12 volt source to a sensor return wire or tried to ground something to a sensor return that was drawing a lot of amps.