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msd 8970
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Author:  themadreefer [ Sat Apr 07, 2012 7:18 am ]
Post subject:  msd 8970

is there a test that can be performed to make sure a 8970 is retarding the timing.

thought it mite be as simple as activating my nitrous system. not as simple as i thought.

timing is not changing at all, when system is activated.


thanks

Author:  rick360 [ Sat Apr 07, 2012 10:44 am ]
Post subject:  Re: msd 8970

Per the instructions -link here http://www.jegs.com/InstallationInstructions/100/121/121-8970.pdf
When each wire is NOT grounded it causes a retard by the amount of that retard chip. You can test it by starting the engine (locked out dist or crank trigger) with a known chip (say 4º) in Retard #1 and when you lift/disconnect the brown wire it should retard by 8º when the wire is grounded the 8º retard goes away.
Do that for each # and you're done.

Code:
RETARD CONTROL WIRES
BROWN    Retard 1, Activated when removed from ground.
ORANGE   Retard 2, Activated when removed from ground.
GRAY     Retard 3, Activated when removed from ground.


Rick

Author:  Ken0069 [ Sat Apr 07, 2012 1:03 pm ]
Post subject:  Re: msd 8970

Good info Rick!! When I first read his post the MSD way of doing stuff, ie, going to ground etc came to mind as my Digital 7 shift controller requires 12v from the ignition switch to the solenoid, then out of the solenoid and in the Digital 7 I believe on the brown wire. MSD makes the ground connection inside the box to make the solenoid activate.

And I believe the old MSD RPM activated switches work kinda the same way.

Author:  themadreefer [ Sat Apr 07, 2012 1:10 pm ]
Post subject:  Re: msd 8970

guess i am little confused, or just can not follow directions well. ](*,)
but according to diagram on page 6, brown wire gets connected to 12v.
so my thinking is if i apply 12volts to brown wire timing should be retarded.

my brain is really hurting just thinking how the ground being removed causes retard.

Author:  rick360 [ Sat Apr 07, 2012 2:34 pm ]
Post subject:  Re: msd 8970

themadreefer wrote:
guess i am little confused, or just can not follow directions well. ](*,)
but according to diagram on page 6, brown wire gets connected to 12v.
so my thinking is if i apply 12volts to brown wire timing should be retarded.

my brain is really hurting just thinking how the ground being removed causes retard.


If you apply 12V OR not connected to anything it should retard. When the 12V is removed, but the control wire is still connected to the coil, it is grounded thru the solenoid coil making it return to "no retard".

A coil is fairly low resistance and will act as a ground path for a higher resistance device if there is no power applied.

Rick

Author:  themadreefer [ Sat Apr 07, 2012 6:16 pm ]
Post subject:  Re: msd 8970

my brain is really really hurting now ](*,) ](*,)

run down of test i did earlier today

brown wire connected to 12v, remove 12v, timing does not retard
brown wire connected to ground, remove ground, timing retards

brown wire connected to 12v side of noid, remove 12v. timing does not retard
brown wire connected to ground side of noid, remove ground, timing ADVANCES

now i really questioning myself on what the h%&! i did wrong,

Author:  themadreefer [ Sun Apr 08, 2012 9:54 am ]
Post subject:  Re: msd 8970

had a revelation this morning while driving back from dads.

after reading all the manuals for all my electronics hour after hour, figure i would tinker with the car this morning.

ended up hooking brown wire from retard box to the activation switch on the progressive controller.(need to remember to pay better attention to all the little details they put in the instructions)

and presto, works like a charm

now only if we can get some good weather this coming wednesday.

later

Author:  Ken0069 [ Sun Apr 08, 2012 10:31 am ]
Post subject:  Re: msd 8970

You're not the only one that has missed those "little things" on MSD stuff as I've done that myself along with thousands of others who like me are somewhat electrically "challenged". MSDs mode of operation doesn't seem to follow along with my "traditional" way of doing things.

But yeah, glad you got it figgered out! ;-)

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