parish8

iTrader: (6)

i am looking at hooking up the ignition part of my megasquirt pcm. it is much easier to tune than with edit. there are ways to use the mega to fire 8 seperate coils but i need to be able to get the coil to fire. seems like most coils just have 2 wires, a hot and a ground, pull the ground and get a spark right?

can i do that with the ls1 coils?

y2khawk

iTrader: (5)

LS1/Truck coils have some smarts to them, unlike the standard 2 wire coils.

Feed the coil a constant 12V, ground the two ground wires. You apply 5V to the trigger input to charge the coil, remove the 5V input and the coil fires.

There is internal over dwell and current limiting, so if you charge too long the coil will fire on its own. You learn after the first time it zaps you

dieselgeek

Sounds difficult or impossible to adapt EDIS to the factory coils then. Jim, we may just want to go with aftermarket coils with EDIS - four of the "two output" coils, like found on DSMs or other wasted spark systems, and figure out a way to make it look clean under the hood...

Technoman64

iTrader: (6)

What is the minimum and maximum dwell time for the LS1 coils?

Just curious.

Dennis

y2khawk

iTrader: (5)

EDIST will run LS1 coils. Alot of setups use the EDIST and Gen3/4 coils.

Don't fear technology

B_Pay

I think you'll need an op-amp comparator circuit with a transistor on the output. This will compare your 12 V from the output of the megasquirt with a reference voltage and the resulting output will either be 0 or 5. This can then be inputted into a JK or RS flip flop circuit.

Unfortunately I don't have much time to research the details and develop the specific circuit but hopefully this helps get you started.

To anyone with electronics background...please correct any misstatements on my part...I don't design circuits for a living.

dieselgeek

Anyone else with more info on running EDIS (this is the Ford EDIS module, said to work in wasted spark config)... not sure if it's the same "EDIST" you are talking about. I have to do more reading on ford's EDIS before I can speak correctly about it... ARGH!

-scott

y2khawk

iTrader: (5)

You got info on how the squirt is driving the EDIS? Where the crank signal goes, what drivers the the 908 in the squirt is using, etc.

B_Pay, you're making it FAR more complicated than it has to be.

The EDist is used on the FAST system. The Ford EDIS (i'm guessing) is nothing more than a high current driver to inferface w/ dumb coils.

Waste spark, just pair up the LS1 coils. Pair the trigger lines for 1&6, 8&5, 7&4, 2&3.

If the EDIS is doing the crank decode for the squirt i can see it taking a little work. A simple transistor inverter inbetween the EDIS and the coils will solve that issue. About $3 in parts.



I still don't get why you want to remove PCM control of the coils. Especially w/ an automatic trans.

dieselgeek

All I know is fomr a few minutes of reading: EDIS receives a signal from the VR sensor, getting it's timing information from there. It runs in 10 degree advanced mode (limp mode) until it receives a "SAW" (spark advance word" signal from the megasquirt, then you have control over a 50 degree range of timing...


The reason we want to do this instead of factory PCM? SImple: even with Edit, tuning the factory PCM sucks because it takes too long to make changes while tuning. Had we been on the EDIS system with megasquirt, we'd have been able to tune spark as fast as we tuned VEs, on-the-fly. It took Jim 10 minutes to make timing changes, reburn images, etc. Pain in the ***. This is all my opinion, not Jims, but you get my point.

Back to EDIS - I'd rather avoid adding multiple circuits to invert the signal or step it down to 5 volts if I can at all. Adding too many little parts can cause headaches troubleshooting later, but I *DO* like the idea of triggering the factory coils in their own wasted spark method, plus you get single coils for each cylinder then, so we are definitley going to look into this metyhod first. And thank you for the info on how they're triggered!!

-scott

parish8

iTrader: (6)

tuning with edit just plain sucks after tuning with megasquirt, if it wasn't too much work to have mega do the timing i would like to do it but this isn't sounding real easy.

another reason to try and get mega doing the timing is we(scott and I) might try and sell a few preassembeled megasquirts and if we could figure out some timing control then guys with sticks might not have to buy any other tuning stuff like edit or efilive.

Pro Stock John

iTrader: (34)

HP Tuners loads in about 35 seconds.

dieselgeek

Megasquirt loads on the fly and costs a few hundred bucks. I'm not sure how much HP tuners costs, but even 35 seconds would have been helpful at the dyno session.

P Mack

iTrader: (6)

Using the ls1 coils in waste spark would fire them twice as often,correct? Would that give they have enough time to charge at high rpm?

Technoman64

iTrader: (6)

Being a low ohm design I would think they would be good to at least 8,000 RPM or more without any issues. I have seen .7 ohm coils work good to 16,000 RPM in wasted spark mode in a motorcycle application. The coils were designed for fast charge(short dwell time) and suffer slightly on burn time compared to some automotive coils I have tested. I can get a peak of 840 volts dc on the primary and 1,4kV AC on the primaries using 1,200 volt IGBT's to drive the coils. Oops I am getting off the subject.
Have they made any more progress on the Ultra Mega Squirt controllers? I believe that they Ultra will be using the HCS12 MCU with more control options.

Another idea would be to use a MCF5232 Eval Board and hack it to the MeagSquirt control board. These cost $250.00 and have 2 meg of Flash and 16 Meg of Ram on a Credit Card sized board with a Serial, Ethernet, and CAN port I believe. The MCF5232 has a 16 channel eTpu module that could take the signal from the Mega Squirt and provide all of the timing signals needed to run the LS1 coils. You can take a signal and use the Angle Mode of the Time Proccessor Unit and produce an angle clock timer system that would control 8 other pins on the eTpu to run the coils.

Just a thought, I am known to make things too complicated at times so keep that in mind.

dieselgeek

LOL are you an EE by chance?!?

UMS is still in development (working on PCB revisions), MS-2 however is in beta testing with a group of senior 'squirters...

I see you are from Decatur! I grew up outside New Haven, just up the road from you guys...

I'm certainly open to suggestions for how you think we should fire LS1 coils with an EDIS controller... but the idea must meet a few objectives:

-cost effective
-simple
-reliable

I'm sorta leaning towards MSD aftermarket coils that are designed for wasted spark, like 4 DSM style coils... but it would be best if we could find the right method of triggering the original factory coils, which I understand are capable of lighting high boost mixtures easily?

-scott

y2khawk

iTrader: (5)

I already told you how

You won't have any problem running them paired. And considering you already have them.....

Is the squirt setup to just provide the spark angle? Or will it modify dwell as well?

And yes, I'm an EE. If there's one thing I've learned over the years, KEEP IT SIMPLE!

You can get fancy but adding more controllers to the design, but why?

Just make the EDIS out compatible with the Coil in and call it a day.

hell, i'll spin you a PCB for it. You pay for it

Technoman64

iTrader: (6)

I have purchased one of the LS1 coils from NAPA. Connected it to HCS12 Eval board and using a 0-5 v PWM signal can fire the coil no problems. It seems to want at minimum 2mS dwell time. Shut off(maximum) dwell I do not know until I can get my scope connected.
Thanks for the info Y2KHawk, one more question is it posible to turn the coil OFF without a spark if a no-start condition occurs? i.e.- reduce the 5 volt drive in a linear mode? Slowly turning off the driver and using it as shunt? I have done this with IGBT's. I am just curious if you had ever done this. I do this for V-Twin ignitions that are running nitro. A mis-placed spark is very nasty in that situation. I realize they start on gas, I just track the crank trigger pattern and kill the coils with no spark if an error occurs while running. Then bring it back if the sync is correct( and not to many revolutions have occered since the shut down error). Just wondering if I could do the same with the LS1 coils.

dieselgeek

This is some awesome information. Can't thank either of you enough!!!! We'll post up when we try adapting the EDIS system to the LS1 coils. I already got someone from the MS-EFI forums to draw up the simple circuit diagram to convert to a 5v trigger. I know dwell is handled inside the EDIS units themselves, not sure about dwell time etc.

thanks again,
-scott

Technoman64

iTrader: (6)

Wiring pinout I used for testing. I used the left side terminal as #1.

1 = +12 volts(battery)
2 = 0-5 Control, 5volt to turn on, 0 to fire.
3 = Battery ground
4 = Referance ground(ECM and/or control ground)

3 milli-second dwell(on time before firing) seems to be about the best.

Connectors appear to be made by Delphi. You can also solder wire leads to the terminals and then pour epoxy in the connector cavity to seal it. Then use a connector of your choice.

parish8

iTrader: (6)

what happens if you dwell to long? like just leave it on all the time other than when you fire it?

i didn't know it was a 5on and 0 fire set up. seem like you could use the 12v you have at the coil and send it thru a resistor to the 5v on and then have the mega/edis just ground that termilal out when you want to fire. that would take nothing more than a resistor at each coil to make them work but there would be no dwell control.

sooo, what happens if you over dwell? seems to me even at 6000rpm and fireing in a wasted spark set up you would have 10ms total between cycles. at idle it would be close to 100ms. can you dwell it that long and then fire and be ok?