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Is this an Aftermarket Tach Adapter?

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BabeTheBlueOx

Is this an Aftermarket Tach Adapter?

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!

1985 F350 4x4

Pete Whitstone

Re: Is this an Aftermarket Tach Adapter?

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.

81 F150 Flareside, Edelbrock Pro Flow4 FI, hydraulic roller 351W, E4OD, 4x4, BW1356
92 F150 RCLB 351W E40D BW1356 mostly stock

BabeTheBlueOx

Re: Is this an Aftermarket Tach Adapter?

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.

1985 F350 4x4

Gary Lewis

Re: Is this an Aftermarket Tach Adapter?

Administrator

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

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

mat in tn

Re: Is this an Aftermarket Tach Adapter?

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

Re: Is this an Aftermarket Tach Adapter?

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.

1985 F350 4x4

Gary Lewis

Re: Is this an Aftermarket Tach Adapter?

Administrator

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

Gary, AKA "Gary fellow": Profile

BabeTheBlueOx

Re: Is this an Aftermarket Tach Adapter?

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.

1985 F350 4x4

mat in tn

Re: Is this an Aftermarket Tach Adapter?

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