MSD Digital 6AL pn 6425

[STEVE-O]

Originally Posted by Voyager

Eric,

Don’t think we’ve established that the MSD 6AL has failed.

After installation, my amp gage is bouncing/fluctuating.

Is that a failure or is it a normal condition for an MSD box?

Bob

The ammeter bounce may be unrelated to the MSD box installation. There is a known issue with the SPF wiring that causes the ammeter bounce. It has to do with the sense wire in the voltage regulator and involves moving the sense wire to a new location to fix the issue.

There was a fix published at the SCOF site and they will have more info.
I cant recall the actual fix that was found since it was over a year ago and since I dont have my car anymore, I'm not up on the changes.

Hope this helps!

[Eric 1151]

Since you haven't mentioned an amp gauge problem prior to the MSD Digital install, I am assuming the gauge was ok. Since the only change is the MSD install, that's where I would start looking. The problem with the amp gauge on SPF's was that the wiring was designed for an idiot light, not a gauge. Changes at the voltage regulator was the fix. Not sure what they were. Anyway, that's what Mike from Dynamic told me, over 10 years ago.
Eric

[Gaz64]

Just rereading.
Mike says the amp gauge goes from 0 to +25.

That is charging, not discharging.

Can we get some more clarification on this?

Maybe how the MSD system was added to the car, can Mike post a circuit diagram please?

[STEVE-O]

Originally Posted by Eric 1151

Since you haven't mentioned an amp gauge problem prior to the MSD Digital install, I am assuming the gauge was ok. Since the only change is the MSD install, that's where I would start looking. The problem with the amp gauge on SPF's was that the wiring was designed for an idiot light, not a gauge. Changes at the voltage regulator was the fix. Not sure what they were. Anyway, that's what Mike from Dynamic told me, over 10 years ago.
Eric

Well if it was a fix from 10 years ago, it must have been something else related to the ammeter.
It could be that the recent MSD install just made the ammeter issue more noticeable.
The most recent ammeter fix from a couple of years ago is this:

Bouncing Ammeter

[MGlad]

Hey guys, my Cobra is packed away, not really accessible. I was going to suggest reading the "Bouncing Ammeter" link that Steve-O posted. I won't be addressing this issue for a while, but I'll keep you posted. Has anyone read up on the SCOF tech article on this?

[Blas]

I find it interesting that you had a non-bouncing AMP meter before the addition of the MSD box and a bouncing AMP meter after the MSD installation. Some people have this problem and some don't. Doesn't make sense to me why everyone doesn't have the same problem who has an MSD installed. Got to be on how it is wired into the system. Try separating the MSD wires to and from the coil and distributor. Did they use the MSD supplied wiring to the coil and distributor or make up new wires? Are the zip tied together? Are they longer than what is supplied in the kit?

The SCOF fix works well to cure the bounce. But I like to know why it is happening.

Yes, I have Wiring Diagrams available for the Superformance MKIII (4 versions), Wiring Diagrams and Owner's Manuals for the Superformance MKII Slabside and FIA and Wiring Diagrams for the Superformance GT40 (MKI and MKII versions)
I also have Wiring Diagrams and Owners Manuals for the Shelby 7000 and 8000 cars both Anniversary and non-Anniversary editions.

Really a must-have for owner's.......

[Voyager]

Originally Posted by Blas

I find it interesting that you had a non-bouncing AMP meter before the addition of the MSD box and a bouncing AMP meter after the MSD installation. Some people have this problem and some don't. Doesn't make sense to me why everyone doesn't have the same problem who has an MSD installed. Got to be on how it is wired into the system. Try separating the MSD wires to and from the coil and distributor. Did they use the MSD supplied wiring to the coil and distributor or make up new wires? Are the zip tied together? Are they longer than what is supplied in the kit?

The SCOF fix works well to cure the bounce. But I like to know why it is happening.

Yes, I have Wiring Diagrams available for the Superformance MKIII (4 versions), Wiring Diagrams and Owner's Manuals for the Superformance MKII Slabside and FIA and Wiring Diagrams for the Superformance GT40 (MKI and MKII versions)
I also have Wiring Diagrams and Owners Manuals for the Shelby 7000 and 8000 cars both Anniversary and non-Anniversary editions.

Really a must-have for owner's.......

Yes – AMP meter was stable prior to MSD installation. Now bouncing. Took a quick look at it this weekend. Both coil wires were loose. Now tight. Did not fire it up to inspect gauge because I was working on wife’s SUV and didn’t want the fumes in the garage. Will check later.

In case it is not fixed, will see if I have SCOF fix in my garage binder. Will contact you shortly regarding a wiring diagram.