Researching for going ignition control

[opethmike]

Hey guys,

I am thinking about going ignition control over the upcoming off-season. I like to do research well in advance, so hence why I am asking questions a few months ahead of time.

I think I have a pretty good grasp of it. I know I need to :

Tack down the mechanical advance weights
Attach a wire from coil negative to the ignition output pin (S5 on my relay board)
Set the jumpers in the ECU to VR input for ignition
In TunerStudio I'll need to the ignition mode to basic trigger, and set the offset to match the base timing of the distributor
Set up the ignition table
Get the VR signal from the distributor and wire it to the tach input and VR ground on the relay board

The last item is the only one I do not comfortably understand. I am not sure how I am physically supposed to get the signal from the distributor. I know is from the wire coming out of the distributor wire, but that wire has two layers in it. So, if someone could show me a picture of how they are getting the signal from the distributor, I would really appreciate it. Also, if someone running ignition control could share their MSQ with me so I can explore the configuration, that would be great too.

Thank you in advance,

-Mike

[Spittybug]

Not a perfect tune, but should suffice for your education.

The wire from the dizzy VR is very straightforward. I'll see if I can get you a picture.

BTW, I think Ian successfully used ties to disable his mech advance.

Going full spark control gives you a world of opportunity but also a huge temptation to tinker. And of course, there is also the risk of over advancing and detonation...... Like chess, a minute to learn, a lifetime to master.

[opethmike]

Thanks Owen. I realize the question about the VR wire is probably silly, but wiring is not my strong suit, so thanks in advance for the picture

[AdmiralSenn]

I still can't get a decent picture (my phone's camera is terrible) but here's how I did it (reposted from Facebook):

I have the fancy shielded tach in wire from MS split with the shield going to the two black wires on the end of the ignition computer connector and the center lead going to the blue wire directly next to it. That's it. I even managed to run the wires so all you see is one additional lead heading into the rubber boot. Provides a tach signal with or without the ignition ECU connected.

That's also a handy place to tap in the gray/white whire for coil negative if you don't want to run it all the way to the coil or haven't already done so.

[opethmike]

So as I remember, the 3.57 boxes don't play nice with ignition control for our cars, but DIYAutoTune came up with a fix for it. Anyone know/remember what that was?

[opethmike]

Hey guys,

Would one of you mind posting a picture of how the VR signal from the distributor is wired, please? Adam's description is good, but I'm more of a visual learner, and want to make sure I have it right.

-Mike

[opethmike]

Okay, I think I've got it now. I pulled out the ignition ECU, and peeled back the rubber boot. I see exactly the wires that Adam is talking about. I'll make up some temporary wires with terminals on them just to see if I can properly read RPM off of them before I hack into the wiring to solder things together.

Now I just need to know about the 3.57 box fix for the DeLorean. Would rather do that than get a 3.0 box just to go ignition.

[opethmike]

And to keep babbling - I have been reviewing the ignition table in Owen's tune (well, at least the most recent one I have), and some areas get advance as much as 53 degrees. This seems really high to me. Am I missing something?

[Spittybug]

And to keep babbling - I have been reviewing the ignition table in Owen's tune (well, at least the most recent one I have), and some areas get advance as much as 53 degrees. This seems really high to me. Am I missing something?

I fubared my ignition table somehow and am in the middle of dialing back in. Too little advance and it drives like a school bus as I have discovered.

Our cars really seem to like a goodly amount of advance right off of idle. Stock engines immediately see an additional ~10* of advance when the throttle is depressed. That's about 23* total and then as the RPM increases it more than offsets the decaying vacuum advance.

Static is ~13*. The vacuum advance goes from 20* of advance under the highest vacuum levels (butterflies closed, deceleration) to essentially none at wide open throttle. Mechanical goes from 0* advance at 1,000 RPM to 20* by about 3,500 RPM. So, if you think about a high RPM deceleration, 13* + 20* + 20* = 53* But this is unloaded, transitory, in the right lower quadrant of the kPa/RPM table. Maximum steady advance would appear to be in the high RPM cruise region..... 13* + 20* mechanical + ~10* vacuum or a total of about 43*. On acceleration when kPa is near 100% continuously, the advance is 13* + the increasing mechanical advance, so it doesn't exceed ~33*.

I have a good spreadsheet for this shit.... but dialing it in is tough without a dyno.

[dustybarn]

The wire that connects to the distributor sense coil terminates in a Bosch PFI injector-style connector. I used a female injector connector and ran a dedicated twisted pair cable through the bulkhead, ignoring the original coaxial cable. I hooked up the cable to an oscilloscope and spun the distributor by hand to be sure I had the correct polarity. Now, the GM HEI module I used triggers on a downgoing zero crossing; I don't know what the MS VR circuit expects to see.