Is this an Aftermarket Tach Adapter?

[BabeTheBlueOx]

Title says it all..

I'm digging in to some wire harness cleanup and testing after getting stranded on the side of the road with no spark, wiggling some wires, and getting moving again.

I'm not sure what this is, and I'm not sure that the sticker on it came with it originally or someone slapped it on.

Also, there is no tach gauge.

Thanks in advance!

[Pete Whitstone]

The location, the plugs going to it, and the wire colors all indicate that it is some version of the Ford Duraspark box. I have never seen one quite like that, but I'm not sure what else it would be.

[BabeTheBlueOx]

After another bout of googling, I'm thinking you're correct.

Someone installed an MSD Multiple Spark Discharge unit in the truck at some point, and I was thinking that replaced the ignition control module, but maybe that's not right.

[Gary Lewis]

It does look like maybe MSD made a direct replacement for the DS-II box.

[mat in tn]

I would have expected msd to make a better fitting label than that. I would imagine that this is an "in field" modification. possibly by someone with an extra sticker laying around and a giggle. kids love stickers. and old cars/ trucks seem to be victims often.

[BabeTheBlueOx]

Turns out it is the ignition control module.  After unwinding everything, it turns out it's not hooked up to anything.  There's a separate MSD multi-spark unit that replaces it for (and is required for) or the MSD Pro Billet distributor.

The wire I was unsure of, that came from the ICM bundle of wires and ended at the multi-spark module, is just ignition +12.

[Gary Lewis]

Glad you got it figured out.  So are you pulling that module off to clean things up?

[BabeTheBlueOx]

Gary Lewis wrote

Glad you got it figured out.  So are you pulling that module off to clean things up?

Yes, I think so.  It's just taking up space and looking messy at this point.

[mat in tn]

you have an msd system? there should be a tach output on it. a green wire if I remember correctly.