Jeff20B

Here is a nice diagram that RX-Midget made. It shows how to hook up a 2nd gen trailing coil to a 2nd gen leading ignitor for use on 1st gen distributors. I'm going to have it on the trailing side and an MSD 6AL with a 2nd gen leading coil on the leading side. It should do quite well.

83turbo

I'm a little iffy on connecting a pickup coil to a 2nd gen lead

ignitor, but hey if it works... It's alot more powerful than the

older ones. Also you should probably bypass the 0.35 ohm resistor

that lives inside the module - the trailing coil is already 0.35 ohms

more than the leading coil.

Jeff20B

Thanks for the tip.

Jeff20B

My FC leading ignitor has two blacks, two browns, and one red wire. It doesn't match the diagram. I'll need to do a bit of research before hooking up any wires. I don't need another burned out ignitor (two dead J-109s in a row that I though were good, heh).

83turbo

On the FC lead ignitor-

Case is ground

There should be a two wire connector - one wire is red, the other is off-white/tan/

whatever. The red is the trigger. The other wire is power. It also connects to the

coil. Note that some modules have the resistor on the + side of the coil and some

have it one the - side.

The two black wires you mention should be connected together from the factory.

This is the coil - wire. One of the black wires hangs loose - it's a test point for

a tach or something.

Jeff20B

That makes sense. Yeah, I figured the black wires were for the C/- side if the coil and tach signal. That leaves the red(1) and tan/brown wires(2). Since I'm mounting the trailing coil to the leading base, that bullet connector for the tach signal will come in handy. I'll also bypass the resistor. Lastly, I've got to determine whether the red wire you mentioned is the same as my red wire, likewise for the brown wires. To give you an idea, the resistor has brown wires connected to it. I've seen a picture that showed black wires connected to it. I know the FB ignition stuff backward and forward, but I'm still learning about this FC stuff. Thanks for the info. Any other tips or tricks you can think of?

83turbo

The red wire (trigger) is soldered on to a terminal labeled "?GT"

(can't read the 1st character because of the wire). Tan goes to

"B??", and black goes to "C".

The resistor can be located on the tan or black wires - I've

seen both configurations.

Note that this ignitor doesn't do active dwell control - it just

turns on the coil when the red wire is + (although after a couple

of seconds it will shut off). So, if the trigger pulse is too short

it really won't work right.

Also the lead coil has the lowest primary resistance of any inductive

coil I have ever tested. Why the trail is different I don't know.

Also, the trail coil has a "secondary gap" inside it - if you

try to measure secondary resistance, it appears open.

ArrX7ahh

So what is the most optimal way of using the second gen coils and ignitors on a 1st gen?

Jeff20B

It depends on what you want to do. A trailing coil will fit on a leading base. Then it can be hooked to the cap for regular trailing ignition, but with a hotter spark than stock FB stuff. No ballast resistor required.



I haven't had a chance to go through the wiring of my FC leading ignitor to an FC trailing coil yet. The wire colors of mine differ from the block diagram and what 83turbo said (sort of). I am busy with too many other things to give this FC ignition stuff some quality time. I'd like to get to know it as well as I know the FB ignition stuff. I'd rather not risk damaging anything until I'm more familiar with it.

83turbo

Okay, so I gave it a whirl....1980 distributor (electronic but

without the ignitors) and connected one of the pickup coils to

a 1986 lead ignitor. Yes, it does produce spark, but there appear

to be some problems. First, the signal from the distributor is weak

at low RPM. I don't have a solid figure, but cranking would seem

iffy. Next I connected the 'scope so I could look at the trigger

signal. The positive side looked sort of narrow - since the lead

ignitor is the "dumb" variety, this could pose a problem with coil

saturation time. I would assume the trigger would get proportionately

narrower with increased RPM, but didn't take it up that far due to the

rickety condition of my distributor tester. Finally, I scoped the

current draw by the coil. I could see the current ramp up, but did

not plateau like it should when it hits the current limit imposed

by the ignitor. I tried triggering it with an MSD tester, and

verified the current limit was hit as expected.

So how much current does the '86 ignitor dump through the coil?

I'm having a hard time getting a straight reading today, but I recall

it is in the 7.5 to 8 amp range, so it's at least as powerful as

the MSD "Blaster" inductive ignition box. I haven't seen any other OEM

inductive ignition this powerful. As for aftermarket, Electromotive

is 10 amps, and god knows what the inductive part of the MSD-10 is.

Anyway, this should work:

Get a PNP transistor (2N3906 or whatever). Emitter goes to +12.

Collector goes to red wire on the '86 ignitor. Base goes to a 1K

resistor. Other end of the resistor goes to both the J109 ignitor

output and to another 1K resistor. Other end of this resistor goes

to +12v. I haven't tried this but it looks like it should work.