Connecting MSD 7AL to FAST

[turbo_bu]

I'm finally getting ready to hook up the FAST to my car and need a little help with ignition wiring. The FAST I have is a sequential unit, the ignition box is an MSD 7AL-2. I have the crank and cam triggers wired up but need to know which wire from the FAST to connect to the white wire on the 7AL-2. Reading the FAST manual shows two different connections for GM HEI setups (closest thing I could find for my setup) but it does not discern where the wires go to the GM wiring. It only show the A B C and D pins and says hook them to GM pins A B C and D. Looking at the FAST wiring diagram shows the four pins A-EST, B-Crank Refence, C-Bypass, D-Distributor Reference .... which one of these needs to be connected to the white (trigger) wire on the MSD 7AL-2?

 

[HighPSI]

I believe it's the "Points" wire.

 

[turbo_bu]

I remember hearing that it was the B wire ... but that doesn't look right to me.

Lance or Craig , can you help provide some guidance.....

 

[KendallF]

Originally posted by turbo_bu
I'm finally getting ready to hook up the FAST to my car and need a little help with ignition wiring. The FAST I have is a sequential unit, the ignition box is an MSD 7AL-2. I have the crank and cam triggers wired up but need to know which wire from the FAST to connect to the white wire on the 7AL-2. Reading the FAST manual shows two different connections for GM HEI setups (closest thing I could find for my setup) but it does not discern where the wires go to the GM wiring. It only show the A B C and D pins and says hook them to GM pins A B C and D. Looking at the FAST wiring diagram shows the four pins A-EST, B-Crank Refence, C-Bypass, D-Distributor Reference .... which one of these needs to be connected to the white (trigger) wire on the MSD 7AL-2?

It should be the EST (A) wire..the crank and cam trigger signals should be hooked up to B and D, respectively. This is going by what you've posted here; I don't have the FAST diagram in front of me.

 

[Craig Smith]

Well, you said HEI is "close" to what you have, but what is it exactly? The points wire in the FAST harness won't be used if you are using an HEI ignition. The MSD will be driven by the spark module in the distributor with an HEI system.

 

[turbo_bu]

Craig,

The system consists of the following:

MSD Crank Trigger
MSD Small Block Chevy Distributor with a once per rev mag pickup built into the distributor.
MSD HVC2 Coil
MSD 7AL-2 Ignition

Both the mag pickups are connected to the FAST. The 7AL-2 is connected to the coil. I'm trying to figure out which wire from the FAST system is needed to connect to the 7AL-2 (MSD white wire)to tell it when to trigger the coil.

Reading the FAST manual only talks about the OEM connections which are supported. It does not provide any description about which wires do what other than looking at the pin out on the ECM. I guess using the HEI description is wrong, but I did not see any other listing which was similar to my setup.

 

[berrelauto]

You hav a Inductive pickup ignition system. Hook the White points wire from the FAST harness to the MSD points input. 1st page of Manual under POINTS.

 

[turbo_bu]

From FAST site:

Points
Unless specifically noted otherwise, this wire is to be connected only if an inductive pickup ignition system is used. Connect this wire to the points input wire on your aftermarket ignition system. Do not connect this wire if you are using your factory ignition system.


I gather that the MSD classifies as an inductive pickup system. I wasn't sure since they are actually magnetic pickups. Maybe the manual could list aftermarket ignitions as an option to help clarify.

Thanks for your help