j91z28d1n2o wrote:

QUOTE:
the only thread I found on tgo about the edis says they can't be made to work.



I really really hope you have some luck with it.

I know, that's all I found too.

No explanation as to why, or any indication of what might be needed to make it work.

From what I've read in the MegaManual documents and other information sourced from the internet in addition to how I have my test bench set up, I think it should work.

I think I'm going to mount the wheel to an electric motor that I have and see if that will allow me to test the ideas I have on the bench. I'm really hoping that it works, just for the simple fact that I want to add DIS to the T-bucket. I just think it would be very cool to have an old school rod, with new technology on an old looking intake.

EDIS is fine up to the point where you have to feed it a timing signal.
Then it sorta speaks a different language.


I've been trying to figure out a way to do what that flip flop circuit does...
the real problem, is that the EST pulse that gets generated is for the *next* firing event, not the current one.

Oddly enough, the easiest thing would be a cheapie Atmega processor that took the 7/9 tooth circuit, generated a REF, and then would feed the EST pulse to the appropriate pair of LS1 coils (firing waste-spark). This wouldn't require any power circuitry at all, since the ls coils are self powered and use a trigger pulse.

I have $59 working on a '95 3.4L Chevy V6 running the 7730 ECM and DIS in an '86 Fiero GT. The 3.4L has the 7x reluctor wheel on the crank. It would not even start using the 30# starter BIN until I adjusted the timing advance to 100*.

DIS will work but be prepared for some crazy numbers due to the way DIS figures advance for the next event, not the current one.

yeah.. the v6 stuff seems to be pretty easy to come by.


the v8 is a pain since gm seems to have only used it on a lt5 zr1. those are rare and cost a shit ton.

j91z28d1n2o wrote:

QUOTE:
yeah.. the v6 stuff seems to be pretty easy to come by.


the v8 is a pain since gm seems to have only used it on a lt5 zr1. those are rare and cost a shit ton.

Which is precisly why I'm going to be playing with EDIS. I have several GM DIS modules and coils, that I could add to the Datsun, but what fun would that be? No I just need to prove if it will or won't work and why.

I'm also trying to come up with how dual 4 cyl modules would work, since they would fire twice as often as they need to. Due to the way the trigger wheel is set up. I had even thought about using dual trigger wheels with the notches tightened up and only on half of each wheel, and installed 180* apart, but that still wouldn't work.

The testing I've done with the JimStim on the bench connected to the GM ECM, indicates that the signals in and out of the ECM should work. The JimStim uses the same setting for "Distributer" and "EDIS" ignition trigger signal. Also disconnecting the EST wire (white) will drop any RPM input to the ECM, so it seems to be needed for the sim to function.

Time will tell.

I now just about have the front suspension completly reinstalled on the Jimmy, tall spindles, custom upper control arms, etc. I just need new outer bearings and maybe some rotors to roll it away to storage for the winter, so that I can get the Datsun in the garage.

all I can say is good luck man. I hope something works.


I know there's a lot of bad info out about the n* setup. but while searching around I found a post on a fiero site about the n* icm outputting a whole bunch of setting off that one wheel. may have to do with the duel crank sensors. something like 4x 8x 24x 36x. I'd have to find it again, but if it outputs a bunch of different ones, and you just hook our ecm to the one we need. maybe we can say hook up to the 36x and run a simpler crank wheel to get the 8x we need out of the icm.


if that makes any sense.

if the ford stuff don't work out for you, here's a little more on the n* stuff.

this is .zip is from jwscab at thirdgen and i found a link to a place that makes custom trigger wheels, but its in the uk lol

the n* icm has a x4 output and a x24. i have a feeling that doesn't help anything. blah

http://trigger-wheels.com/store/index1.html?lang=en-uk&gclid=CKnH7-G1w5cCFYoH3goda20JSw

they do seem to be running v8 rover stuff. which may be something, but no clue how hard it would be to get parts over here. or if it would even work with our ecm's.


i now see what most people that look into changing to coil packs on thirdgen give up pretty quickly.

j91z28d1n2o wrote:

QUOTE:
if the ford stuff don't work out for you, here's a little more on the n* stuff.

this is .zip is from jwscab at thirdgen and i found a link to a place that makes custom trigger wheels, but its in the uk lol

the n* icm has a x4 output and a x24. i have a feeling that doesn't help anything. blah


i now see what most people that look into changing to coil packs on thirdgen give up pretty quickly.

I think the N* could be made to work, although it's a pretty complicated wheel/sensor setup. You don't need the cam sensor.

When you start pricing the parts out, it gets expensive kinda quick.

A gadget to process an 8-tooth wheel and fire LS coils would be much cheaper.
It'd also be neat to have a gadget that would convert the GM EST to EDIS SAW. This would allow you to run EDIS correctly from a GM ECM. Ideally, you could have the gadget do either one, selectable.

A modification to the megajolt/jr SW so that would accept EST as an input vs. using the 'jolt's timing tables, would also get the job done.

QUOTE:
Six_Shooter wrote:

The testing I've done with the JimStim on the bench connected to the GM ECM, indicates that the signals in and out of the ECM should work. The JimStim uses the same setting for "Distributer" and "EDIS" ignition trigger signal. Also disconnecting the EST wire (white) will drop any RPM input to the ECM, so it seems to be needed for the sim to function.

Time will tell. :)

What you'll run into, is the timing/phasing of EST. While the PIP should be good, (as you say, it'll look just like the dissy), the SAW pulse that the module wants departs from GM EST.

A gadget to convert the EST output to SAW, would make everything happy.

The SAW generator here is half the battle... it would just need to read the length of the EST pulse, and spit that out as SAW.
http://www.bgsoflex.com/mjl/mjl_edis_stim.html


*EDIT* - Clarification...

SAW is a pulse-width representation of timing- a shorter pulse results in earlier timing, a longer one, later timing.

EST is a bit different:
http://www.megamanual.com/ms2/GM_7pinHEI.htm

EST specifies not only the timing, but the dwell as well. In addition, the falling edge of EST is the firing event itself... it sorta mirrors the charge/collapse of the coil field.

To measure what EST was commanding for timing, you'd have to time the falling edge of EST in relation to the next REF pulse. Then, after subtracting out any ignition base offset, you could calc a SAW pulse and output it.

This would imply that you'd always be delivering SAW 2 pulses later, since EST is one pulse delayed already, and it'd take at least one pulse worth to do the calc.

All of this could be done within the stim circuit above, with some S/W tweaks.

Just thunkin' out loud...