Autosport Labs

I wasn't sure where to post this. Anyway I'm looking to setup ignition on my motorcycle and I have read when assembly my MegaSquirt about using VB921 to directly control a coil (as long as you know the dwell!), it's here near the bottom: http://megasquirt.sourceforge.net/extra ... wheel.html

I was looking for used EDIS systems and got to thinking, why do I want to bother with that. I'm looking for a <$100 system and was hoping MegaJolt can do this so I can still use my MegaSquirt in other applications (otherwise I'll just have to put EFI on the motorcycle as well :p). Anyway, what's a good sensor/input that MegaJolt prefers if it was coming in directly unfiltered and can MegaJolt be setup to use two VB921s to control two coils in a wasted spark 4cyl application?

Lastly, upon using your ordering page I got the following errors from digikey, can anyone point me to the right items?
1 1N4742AMSCT-ND D5 Value add packaging not available; alternate packaging exists.
2 1N4733AMSCT-ND D1 Value add packaging not available; alternate packaging exists.
3 AE7216-ND MJLJ IC SOCKETS Please Contact Digi-Key
Are these just the molex connectors? Which parts do I not need if I just buy brent's $9 connector package?

TPS stuff, which I don't think I'll be using
1 M7010-ND L1 Minimum quantity not met; see price break.
2 399-1882-1-ND C13 Value add packaging not available; alternate packaging exists.
3 1N4733AMSCT-ND D7 Value add packaging not available; alternate packaging exists.
4 399-1416-ND C14 Minimum quantity not met; see price break.

Another final question, I just remembered that I meant to ask about TPS. Can MegaJolt use both MAP and TPS? I know MegaSquirt does, thoguh I think just for fuel, but I'm thinking that MAP gives me a good idea of the load but TPS can be used for accel and decel changes. I know my MR2 advances the timing when I get off the throttle for some reason and we enrich fuel during heavy throttle, is there any reason to advance or retard a bit during heavy throttle? Things like that.

I'm sorry for my overly broad questions.

MJLJ can't connect directly to VB921's or be used with any other sensor.

MJLJ receives a PIP signal from EDIS where the width of the pulses indicate the RPM. The MJLJ then computes the required advance (including the effect of the current TPS or MAP values) and sends a SAW pulse back to EDIS, the width of which indicates the advance that's required.

The EDIS turns the VR sensor signal into the PIP signal and turns the SAW pulse into timed events to switch the wasted spark coils on/off using its internal power transistors.

http://www.bgsoflex.com/mjl/mjl_edis_summary.html
and
http://www.picotech.com/auto/tutorials/ ... nals2.html
..make interesting reading

Neither of these signals (PIP and SAW) and this mode of operation are much good for being replaced with an alternate sensor or directly controlling ignition events via VB921's etc

MJLJ can either be TPS or MAP driven to give 3D ignition, but not both at the same time. You choose what's best for your engine/ease of installation. You can run without TPS or MAP and then the MJLJ just gives 2D ignition control (ie RPM only)

As Martin indicated, The MJLJ was specifically designed to work exclusively with the Ford EDIS system. Think of it as a symbiotic relationship - the MJLJ and EDIS module together comprise a complete, stand-alone, crank fired, programmable ignition system. A future version of MJLJ may offer direct coil control with all of the obvious and not-so-obvious benefits.

Regarding the Digikey parts ordering: To reduce confusion and to simplify things for people who wish to build their own units, I will be offering a full parts kit and de-emphasizing the digikey order form, as I'm not interested in keeping up in their changing inventory- especially annoying after seeing digikey parts change availability after selecting what appeared to be regularly-stocked items!

To answer your immediate questions- if you have a problem with the digikey items- be it changes in their inventory or generally dealing with out-of-stock situations, look at the description of the item and find a similar part. Also, as a back up, review the BOM (Bill of Materials), and finally, ask here on the forums.

For your specific questions:

D7,D1 are standard 5.1V Zener diodes- you should be able to find an alternate part number, or even get this item at Radio Shack (if you're in the states)
D5: A standard 12V zener diode- same situation as above
The IC sockets are 16 pin DIP sockets-- The molex connector is separate- identified as part 'X2'.

I will endeavor to fix the digikey page in the meantime (really, i will this time)
The current design of the MJLJ only allows MAP or TPS, not both simultaneously.

I hope this helps!
Brent

** update- the V3 DigiKey order page has been changed with updated/corrected part numbers.