BOOT77

Well took a good running car and made it run crappy, I put a msd box on it. I know the box is good because I used it to trouble shoot a car with a diff box not long ago, it's a 6al analog that I've owned since it was new.

1st I unhooked the ecm wire like your suppose to then I fired up the car to set the timing and it barely runs. If I set it to stock it'll die and if I turn it up to 30 it'll run but still very crappy and die if reved. It's a 86 TPI car and the box is wired to the stock HEI distributor. I followed the instructions but my setup is slightly diff, instead of the hei in-cap I am using an external cap coil. I also plan to wire the autometer tach directly to the box but forgot to hook it up so that is not the issue.



-white box wire goes to the brown hei
-red to both pinks
-both power wires directly to batt(10ga used & about 6' each of wire from box to batt)
-coil wires to the same TFI coil that was being used with the HEI module
-wires twisted, even used shielded 16ga wire for the coil(could the shielded wire on the coil be the problem?)
-everything spaced and routed apart, box is mounted under the dash more than 6" away form ecm and the power wires are routed to the drivers side while coil wire are out the pass, white signal wire is away from the coil wires.
-wire extensions from box soldered


I didn't grd the coil to the block could that be the problem?

For those who saw my other thread, I did swap back to the stock module.

blackozvet

save yourself a lot of grief and use the msd 8875 adaptor

https://www.summitracing.com/int/par...8875/overview/

Kevova

I would call MSD tell them which distributor you are using for revised instructions.

BOOT77

MSD sent me that diagram


edit: because I am using an external coil I didn't want to use the adapter and emailed msd, that's when they sent me the diagram. I even brought up the adapter with part num and the guy was like what?

Kevova

Not quite getting the external coil on old style HEI. Coil should be grounded.

BOOT77

It does thru the box, I checked with some guys n they agree that is not the problem.

edit: it'd a better coil and not as hot on the engine, msd dist don't have in-cap coils.

eguyett1985

Have you bypassed the MSD box and tried to set the initial timing as per factory procedure to rule out another issue? The MSD will not have an effect on the timing, that is controlled by the ECM. I have an analog 6AL on my 85 but I'm using the MSD in-cap coil.

BOOT77

I only had to set the timing because I pulled the dist to reinstall the stock module easier. That way I could clean out the old heat paste good and apply new.

wikdwizard

Have you tried it without the box? My first guess would be the dist is off time, but I'm not exactly sure of your chain of events.

BOOT77

If I took the box off I know it would run right, but I want it to run right with the box! I just drove the car before I started the install. I'm waiting on a new box, it seems to be lost in transit.

RICHARD TILL

All coils are not compatable with the 6 AL.
Which are you trying to run?

BOOT77

I used the same coil in my c3 with a 6a box, it's a Mallory TFI.

BOOT77

New msd box and same

BOOT77

Well after checking/swapping several things ignition or other, I reverted back the HEI n TFI coil wiring and the car fired up n ran great. So I know the stock control module I put back in is fine and nothing else randomly went wrong with the car during the install.

Not sure what to try next, I want the msd for retard n limiter.

383vett

I've got the same setup as you with the external coil and HEI 7 pin module. Orange to +coil, Black to - coil. Using the HEI connector; pink to red, white to can't remember and I think black to brown (I'll have to check). It's pretty straight forward.

BOOT77

Yah if you could that would be great! What coil?