Help wiring FAST with MSD 6A

[Hawaiian Turbo]

I need to know if I hook up the points wire from the FAST to the white wire on the 6A. I'm running an MSD 8633 and I read some of the searches, It said to hook-up the crank trigger wire to the dist, and not to hook up the dist to the box. The dist has C+ which goes to the + coil, and C- to to - coil.This is from MSD wiring diagram.
Could anyone list the wiring from the FAST to the MSD 8366 and to the MSD 6A ?

Thanks, Paul

 

[Craig Smith]

Hook the distributor leads to the crank input on the FAST, and connect the points output from the FAST to the white wire on the MSD box. The distributor should not be connected to the MSD box.

 

[Hawaiian Turbo]

Thanks for answering Craig. So it's the C+ to Black trigger and C- to Red trigger? White wire to points on FAST. That's the way I have it hooked up now, and no spark. I set-up the crank 50 degrees BTDC and set rotor to #1. The dist. leads you are re ffering to are the C+ and C-, not the four prong with the REF, Bypass, ground and EST, right?

Thanks, Paul

 

[Craig Smith]

We might be talking about opposite ends of the system so I'll cover both ends:

Black/purple wire from distrib to red wire on crank connector from FAST harness

Black/orange wire from distrib to black wire on crank connector from FAST harness

(Above assumes you have an MSD distributor.)

White wire from MSD to white points wire from FAST harness

Black wire from MSD to negative side of coil

Orange wire from MSD to positive side of coil

I am hoping you haven't connected the black and orange coil wires from the MSD to anything on the FAST.... that's several hundred volts coming out of there!

 

[Hawaiian Turbo]

I don't have any wires coming from the MSD 8366. It has the module inside, so I was wondering if there is a way to get the pick-up pulses through the module. There is a C+ and a C-... A,B,C,D.

I got the car running though. I took out the module, and hooked up the pick-up wires straight to the FAST crank connector.

If there isn't a way to get the pulses through the module, then I was going to get a 85551 and I'm ASSUMing that dist has the black/purple and the black orange wires.

Thanks for your time Craig.

 

[KendallF]

I want to jump in here..

Craig, which rotor on the reluctor do you leave on or does it matter? I thought I'd leave the one that's approx. 60 degrees BTDC. I actually have a bank to bank system so I ASSume I don't even need the sync signal from the distributor. I want to set it up anyway though so that if I swap to sequential at some point I will have the distributor set up correctly.

Thanks!

 

[Craig Smith]

Hawaiian Turbo, sorry I didn't realize that you had the HEI version of the MSD distributor. That changes things a little bit.

Since you connected the pickup wires directly to the ECU and it worked, you definitely have an ECU configured for an inductive pickup crank sensor, like the 85551 or a crank trigger uses. The sensor inside your distributor that feeds the module is an inductive sensor, but all in all you are a little out of bounds with this unit. There are mechanical and vacuum advance mechanisms that you must lock out in order to use it with a computer-controlled ignition. Otherwise you have what amounts to a crank reference angle that changes with RPM. You might want to consider putting this distributor aside and getting one better-suited for your application. I wouldn't recommend hacking up an aftermarket distributor unless necessary. The 85551 will do quite well and would be my first recommendation anyway.

Kendall, just to make sure, are you talking about a setup where you have a crank trigger set at 50 BTDC? If so, leaving a reluctor at 60 BTDC for a cam sensor will work. You are correct in that the cam sensor isn't used by the B2B system. The only part that can be tricky when doing this is getting rotor phase and cam sensor position both correct. When modifying an MSD or similar distributor in this fashion, the only way to adjust each one independently is to remove the reluctor wheel and reinstall it in a position that allows correct rotor phase and cam sensor position. The distributors are configured by MSD so that the rotor and one of the reluctor tabs are perfectly aligned.

Actually, to think out loud a bit, I believe that if you leave the reluctor tab just ahead of the rotor, that will work. The cam sensor signal will occur much earlier than you are planning on now, but as long as it happens between the firing of the previous cylinder and the reference pulse for #1, it will work. Does this sound right?

 

[Hawaiian Turbo]

I'm sorry, I should have stated it was an HEI/external coil at first instead of saying the part number I shall be pulling it out and installing the 85551.

Thanks Craig........ and I'm sure I'll be saying that again and again in the future!!!

 

[KendallF]

Originally posted by Craig Smith


Kendall, just to make sure, are you talking about a setup where you have a crank trigger set at 50 BTDC? If so, leaving a reluctor at 60 BTDC for a cam sensor will work. You are correct in that the cam sensor isn't used by the B2B system. The only part that can be tricky when doing this is getting rotor phase and cam sensor position both correct. When modifying an MSD or similar distributor in this fashion, the only way to adjust each one independently is to remove the reluctor wheel and reinstall it in a position that allows correct rotor phase and cam sensor position. The distributors are configured by MSD so that the rotor and one of the reluctor tabs are perfectly aligned.

Actually, to think out loud a bit, I believe that if you leave the reluctor tab just ahead of the rotor, that will work. The cam sensor signal will occur much earlier than you are planning on now, but as long as it happens between the firing of the previous cylinder and the reference pulse for #1, it will work. Does this sound right?

Craig, this is a S2 Buick; I originally bought the ECM configured for the stock ignition (crank and cam sensors, module/coil pack). I have the stock crank sensor set up and want to retain it, but use the distributor instead of the module/coil pack. I am ASSuming I can just feed the timing output of the FAST into the MSD 7AL-2 as you're mentioning above.

Again, with my current B2B system I won't be using the cam sync signal but I will have to phase the distributor and I'd like to set up the sync in case I later go to a sequential setup. I have a billet MSD distributor (p/n 8551) and it has the reluctor tabs spaced so that the rotor is spaced about evenly between two tabs, not aligned as you mention above. I propose keeping the one that leads the rotor by about 60 degrees.

I guess I have 2 questions: If I need it later, can the FAST be set up for a stock style (hall effect) crank signal and an inductive (MSD) cam signal? And, reading your reply here, does the cam sync exact timing matter, or just the cylinder, so that if I keep the tab leading the rotor, it should be fine?

 

[Craig Smith]

Kendall,

Yes, the ECU can be configured as you mentioned, and you are also correct about the cam sync. We aren't looking for a specific angle for the cam sensor to trigger; it simply tells the ECU that the next crank pulse is for the #1 cylinder. There is a huge window you have to work with. However, make sure it doesn't happen anywhere that you might want the ignition to fire, i.e 10 to 40 degrees BTDC. When those interrupts begin happening at the same time the ECU can get mad.