msd 7 digital

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hangn0ut

hangn0ut

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Location
rialto.ca.
Anybody running this box? Have had one for a long time. Would run fine than refuse to start. Swap a 6 in and no more problems. Did the troubleshoot thing. ( no spark) and even sent it back to the factory. They said it was fine. So I'am going to try it again. Put together a very basic harness for the car as the stock harness was a rats nest. Going to focus on the grounds. Any thoughts or tips? Thanks.
 
If you are using a MP distributor...check the pick up coil air gap....
 
I've seen quite a few MSD box troubles in the last few years. some were mine, others not.

Grounds seem to be the most common trouble spot, followed by not having power and ground directly from the battery to the box.

I have seen a few 6AL digital that were bad from the factory and were sent back. however, they have checked yours already.
 
I'am thinking grounds also. So doing what I can. Even grounding the heads to the block.
 
Digital 7. Think its called 7plus. Not the programmable one. Coil,distributor and wires are all msd. Swap in a 6a box and it runs fine.
 
Box is #7520
Distributor is #8536
Coil is #8252
Wires are 8.5 super conductors (msd).
The coil may appear to be a mismatch,depending on which catalog or chart you have but at $80. a pop the techs at Autotronics assured me it would work fine.
 
is your tach connected to the box? what tach do you have? are you using the magnetic pickup or the white wire? did you bypass the ballast resister? do you just want to sell me the box?
 
Use adequate gauge wiring and ground battery to engine or frame, frame to engine, engine direct to ignition box. I run off the back of the head. Run power direct from battery or starter relay directly to the box with correct gauge wire. Follow rest of the instructions.
 
certain tachs will cause a no run situation, the need to be hooked up with an adapter, msd should have a list for you
 
Thanks guys. Tachs are Autometers. Nice try torkflight! But I can be stubborn at times. Like with the Clutchflite I ran for many years. I'am grounding box to battery with heavy wire. Welded stud to frame to replace thru the frame bolt for battery ground cable. New crimp on cable ends. Even opened up the tips on the male ends of the pin connectors. Big,new AGM battery. But now I need to pull the trans back out and see how to make room for that flex plate shield..... thanks for the input and I will post up results when I fire it up.
 
Follow up on the 7 digital box. No bueno. Did most everything I could think of short of hitting it with 24 volts. The only sign of life was the red led flashing as I worked the trigger wires. So I picked up a 6 digital box. See how it goes. Now my analog 6 box has been doing its thing for me for over 25 years. On many cars. So now I'am thinking 'post mortum autopsy' on that 7. But it's late. Good night all!
 
hangn0ut said:
Follow up on the 7 digital box. No bueno. Did most everything I could think of short of hitting it with 24 volts. The only sign of life was the red led flashing as I worked the trigger wires. So I picked up a 6 digital box. See how it goes. Now my analog 6 box has been doing its thing for me for over 25 years. On many cars. So now I'am thinking 'post mortum autopsy' on that 7. But it's late. Good night all!
Click to expand...

I've run 2 digital 6 boxes without issue. One has been in the car for over a decade. I think you'll be happy with it.
 
How are the plugs are they pretty wet also? I have the same box and no issues at all. I run a 8251 coil instead.
 
Car ran great when I first installed that 7. Drove right onto my trailer to go to the track. And that was it. Dead. But the factory said its fine. Bad box! I still use msd products though. Good stuff.
 
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