My 75 F100 has the early Duraspark EI, the one with the "extra" wire (7 instead of 6). It's running a little crappy and I think it may be the cheapo EI unit, which seems to be running hot as it's melting the epoxy on back. Anyway, I bought on EBay what I think is the orginal EI (Part # DY157), but I'm confused by the wiring. All the diagrams I've seen show a Green, Purple, Orange and Black wire on one of the EI connectors, with the green going to the coil and the other three plugging into the distributor connector. And, that's how my current one is hooked up. Then on the diagrams and my current unit, there is a red, white and blue wire on the other EI connector, which go to the corresponding places on the ignition system.
But, the EI I just got has the red, white, purple and orange wire on the 4-wire connector, and the blue, green and black on the other connector.
So, should I connect it based on the wire colours, or should I ignore the colours and just plug it in?

 

You need Motorcraft part # DY-166 for your '75 application (green grommet module).

Part # DY-157 is for '74 applications (black grommet module), as seen in the link below...

Untitled Document

Here's a list of other manufacturer's and their part numbers for your application, but from my experience most of them, if not all, have deleted the "extra" blue wire from their modules....

STANDARD #LX201
NIEHOFF #FF401
ECHLIN #TP36
BORG WARNER #CBE3
WELLS #F101

Here's a listing on ebay for a Motorcraft DY-166 (no pics) but unless it's NOS it too will only have 6 wires, as the 7th wire (blue) has been deleted on all the newly manufactured modules.

http://www.ebay.com/itm/MOTORCRAFT-D...sories&vxp=mtr

 

Well, darn it. Thanks for the info. Have to track down a 166 I guess.

 

I've been through this ordeal myself with the one year only '75 module, i eventually sourced a NOS 7-wire module on ebay, when/if it ever gives up the ghost i'm just going with an aftermarket MSD unit.

 

Yes, its a pain. I've always been curious about why the post-75 module with the 6 wires won't work. The only difference is that third (blue) wire on the harness with the red and white. Are the dist, coil, and voltage regulator the same on the 75 an 76? If so, I wonder what it is about the 75 that prevents it from working on the 76 system?

 

D4AZ-12A199-C .. Ignition Module (Motorcraft DY-157-B) / Marked: D4AE-12A199-A1A, -A1D, -A2C, -A2D / Obsolete

Last MSRP: $69.40 / Dealer net cost: $31.23 / 59 available NOS from Ford Dealers/obsolete parts vendors.

Applications: All 1974 FoMoCo vehicles only.
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D5AZ-12A199-C .. Ignition Module (Motorcraft DY-166-B) / Marked: D5AE-12A199-AIA, -A1B, -A1D, -A2A, -A2B, -A2C, -A2D / Obsolete

Last MSRP: $142.31 / Dealer net cost: $64.04 / 27 available NOS from Ford Dealers/obsolete parts vendors.

Applications: All 1975 FoMoCo vehicles only.

 

I wish i had an answer for you, but unfortunately i don't, through trial and error i too have come to learn they do not work, at least not in my case, and apparently not yours either.

 

The alternator voltage regulator is the same 1963/81, 1982 thru today / 1963 T-Bird's were the first to have an alternator / 1965: Everything else has an alternator.

In 1982 FoMoCo replaced the points type regulator (D4TZ-10316-A which replaced C3SZ-10316-A) with an electronic regulator. Has a flat cover with MOTORCRAFT embossed on the diagonal.

It bolts right on without any modifications required.
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The V8 dizzy is basically the same 1975/76 (engine size obviously makes a difference). 1977 and later is not the same, the cap has 8 male ends and below it...a dizzy cap adapter.
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The coil used in 1974 w/DuraSpark (D5PZ-12029-A ~ Motorcraft DG-313-A) is 1974 only.
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The coil used in 1975/76 w/DuraSpark (D5AZ-12029-A ~ Motorcraft DG-314) is the same, was also used on 1977/79's (excepting some CA vehicles).

DuraSpark introduced in 1974, but not all vehicles had it until 1976.

1974/75 DuraSpark modules were sooo unreliable that Ford techs began referring to DuraSpark as NeverSpark!

And btw, since the question hasn't been asked: D4PZ-12A112-A .. Stator aka Magnetic Pickup Coil (Motorcraft DU-1A) fits ALL 1974/79 V8's with DuraSpark except 1979 LTD/Mercury Grand Marquis w/351W's and EEC.