HELP: MSD/Mikuni 4AGE Setup

RyanMasahiroSandoval
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Joined: Wed Oct 15, 2014 8:53 am

HELP: MSD/Mikuni 4AGE Setup

Postby RyanMasahiroSandoval » Wed Oct 13, 2021 5:55 pm

Hello all,

Recently I have started installing Mikunis on my 4age. I have finished the wiring and plumbing and when I tried starting it, it wont start.
Its my first time doing anything this big so any help would be nice. I am running a MSD Digital 6AL along with the Tach adapter. I do get spark when shorting the magnetic pick up. I think I have narrowed down the issue to the distributor. When I start the ignition, I do not see the MSD led blink as instructed by MSD when it receives a signal from the distributor. Maybe my wiring is wrong at the dizzy, I included a picture of the distributor that Im running along with spare one I have. Any advice would be much appreciated!

https://drive.google.com/file/d/11SxXx0 ... sp=sharing
https://drive.google.com/file/d/1nzc4J_ ... sp=sharing
https://drive.google.com/file/d/1EGcRhK ... sp=sharing
https://drive.google.com/file/d/1vz27E1 ... sp=sharing

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jondee86
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Re: HELP: MSD/Mikuni 4AGE Setup

Postby jondee86 » Thu Oct 14, 2021 2:37 am

It seems to be very difficult to get accurate information as to how you make an MSD box
work with a Toyota distributor. The 4AGE distributor has VR (reluctor) pickups inside and
MSD instructions only talk about "magnetic" sensors. VR amd magnetic are not the same.
VR outputs a weak variable voltage analog signal whereas a magnetic sensor (e.g. Hall
sensor) outputs a digital on-off square wave signal.

So looking back at what I wrote for someone else here...
viewtopic.php?f=13&t=22357&p=137366&hilit=msd+6al#p137366
... it seems that the VR output from the distributor has to be conditioned into a square
wave to provide a suitable input for the MSD. I don't have time to research it now but if
you can verify what one of those HEI modules does, it might be what you want. And they
are readily available from any junkyard, or you can buy them new :)

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Davegt27
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Location: co

Re: HELP: MSD/Mikuni 4AGE Setup

Postby Davegt27 » Thu Oct 14, 2021 7:01 pm

I ran a MSD 6al with tach adapt back around 2000 time frame
not a big deal

you probably have another problem
like your supposed to run the type of intake manifold that has provision for the TPS
Davegt27 Code One Racing

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jondee86
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Re: HELP: MSD/Mikuni 4AGE Setup

Postby jondee86 » Fri Oct 15, 2021 1:00 am

Basically, as I see it, if you want to run a simple MSD ignition only setup without any
form of ECU, there are two separate matters to be resolved. Ignition timing is the first,
and having a fixed ignition curve (advance vs rpm) is the easiest to implement.

I've just been schooling myself on MSD products and discovered that apparently there
is a new version of the MSD 6AL-2 that allows for an ignition curve to be programmed
into the box using MSD software on a Windows PC.
The Programmable 6AL-2 lets you lock out the distributor and program a timing curve
via a PC. You'll also be able to set a 2-Step Rev Limiter, a retard for use with nitrous and even
a boost timing curve for forced induction engines!

The Programmable 6AL-2 shares the same advanced features of the new 6AL-2 with 535 primary
volts and spark energy reaching 135 mJ! Vibration mounts, wiring and a PC cable are supplied.
Must use MSD Pro-Data+ Software to program.

If this information is correct, then the issue of timing control is covered. Note that
older MSD 6AL boxes do not have the ability to control timing advance... that has to
be done with some sort of add-on "timing box" or simple ignition only ECU.

The second issue is obtaining a 12V square wave output from the distributor suitable
for the MSD input trigger. There are a number of ways of converting the VR distributor
output to 12V square wave. Using an HEI module seems to be one of the more popular
methods. Once those two items are sorted you are good to go. You will need to time the
initial (idle) advance by rotating the distributor, then the MSD box will advance the spark
to your maximum programmed setting by the time the engine reaches 3000-3500rpm.

The MSD box will have a tacho output and it will be a 12V square wave, suitable for
most aftermarket tachos but it will not drive the OEM AE86 tacho. To get the required
voltage spike to drive the OEM tacho you will need either an expensive MSD adapter
or one you make yourself for a few cents using a small relay coil.

With the setup described above you will not need a Throttle Position Sensor. A TPS
is only required if you have some kind of ECU controlling the spark advance.

Long post but it might help you figure where you go from here :)

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Davegt27
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Posts: 106
Joined: Thu Jan 10, 2013 10:35 pm
Location: co

Re: HELP: MSD/Mikuni 4AGE Setup

Postby Davegt27 » Thu Oct 21, 2021 12:28 am

wow the MSD tach adapt was like $32 back when I bought one
and I thought they where over priced then
Davegt27 Code One Racing