Digital 7 7531 problem

[mjmotorsports1]

Having a problem with my Digital 7 ignition, it dies at about 7800 rpms under load.
Car will not refire wait about 2 minutes, car fires right up and drives fine.

Car will do a burnout no problem but either at the top of first gear or just above 7000 rpms the car dies.

I am using a crank trigger that is sent to the DFI and then to the MSD box. I sent out the dfi box and it checked it out perfect. I tried another pick-up and it did the same thing. All wiring looks good, grounds look good. Crank trigger wires are twisted and shielded. Any ideas?

The next test is too swap out the MSD with another unit.

[Sparky]

You may want to try and swap out the Coil, I have had problems like you're describing with the MSD Coils.

Sparky

[Jim Monson]

I agree with Sparky. What part number coil are you running?

[mjmotorsports10]

MSD HVC 7531
If a coil goes bad wouldn't it fail completely?

We ran the car on the chassis dyno about 10 times with no problems and on the last pull at 7800 rpms the ignition died. The only changes we made was adding a second fuel pump and installing a smaller blower pulley for more boost. (we made one pull with the new changes to 7500 with no problems) We had made successfull previous pulls before the changes to 8000 rpms. We never found the problem on the dyno and now it will do it at the track all the time.

MSD tech said that their Digital 6 & 7 boxes are sensitive to noise and grounding. They admitted having problems with the Digital 7 boxes but they cannot recreate the problems at their location in Texas.

[Jim Monson]

I had a coil go bad and it didn't kill the car right off the bat. First I had a miss. Then a bigger miss. Finally the car shut off. I hate electrical problems!

[mjmotorsports1]

I will know include swapping out the coil as well as the ignition box this weekend to try to elimanate the culprit.

What part # coil did you have go bad?

[Jim Monson]

#8261 I think.

[mjmotorsports1]

We took the car out on Saturday at Milan with a new coil and new Digital 7 box and the car went right down the track on an easy pass of 8.15 @ 173.

Now the question is was is the coil or the box? I don't want to plug back in the components to find out which was is the culprit on the track. I am thinking of sending both items to MSD to see if they can figure it out. Any thoughts?

[Jim Monson]

Send them both to MSD for inspection. I had a bad coil and they sent me a replacement.