Duraspark II Ignition Module
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
If it was a diesel truck I doubt it has the correct resistor wire in the harness.
If you don't put a resistor in the 'run' circuit it will continue to cook coils.
There is a ground in the distributor.
Three wires in that plug. (orange, purple, black)
The black wire should ground inside the dizzy.
If the red & white plug of the DSII module are not hooked up correctly you will not have ignition retard while cranking.
This can make the starter labor on hot starts.
If you don't put a resistor in the 'run' circuit it will continue to cook coils.
There is a ground in the distributor.
Three wires in that plug. (orange, purple, black)
The black wire should ground inside the dizzy.
If the red & white plug of the DSII module are not hooked up correctly you will not have ignition retard while cranking.
This can make the starter labor on hot starts.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
DuraSpark electronic ignition introduced in 1974, but not all vehicles came with it until 1976.
1U2Z-12A199-AA (replaced D6AZ-12A199-A - D8VZ-12A199-A - D9VZ-12A199-A) .. Ignition Module-Blue (Motorcraft DY-893) / Available from Ford.
1976/97: myriad FoMoCo vehicles.
Note: 1974 module is 1974 only / 1975 module is 1975 only / Some 1976/79 sold new in CA vehicles used the red module. It was a POS from day one ~ STAY AWAY!
1974, 1975 and 1976/79 red modules were so prone to failure, that Ford techs referred to DuraSpark as NeverSpark!
1U2Z-12A199-AA (replaced D6AZ-12A199-A - D8VZ-12A199-A - D9VZ-12A199-A) .. Ignition Module-Blue (Motorcraft DY-893) / Available from Ford.
1976/97: myriad FoMoCo vehicles.
Note: 1974 module is 1974 only / 1975 module is 1975 only / Some 1976/79 sold new in CA vehicles used the red module. It was a POS from day one ~ STAY AWAY!
1974, 1975 and 1976/79 red modules were so prone to failure, that Ford techs referred to DuraSpark as NeverSpark!
New User
Joined: Jan 2016
Posts: 1
Likes: 0
Hey guys, i have had my f100 for a few years now and am now looking to upgrade my ignition. Im very confused with all the "recurve" and duraspark II stuff. Its a 1981 f100 300 4.9 carburated. So far engine wise it is stock. I would like the engine to live to its full potential. Ive been looking at New Ignition. Pretty lost. So far i bought the Taylor MSD distributor cap. Im not sure what coil to buy, and if i need a new different ignition module to go with it, if at all. Any suggestions appreciated.
1981 F100 4.9 300 Short Bed single cab 2WD
1981 F100 4.9 300 Short Bed single cab 2WD
Thread Starter
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Cargo Master
Joined: Dec 2004
Posts: 3,362
Likes: 22
From: Florence, SC
Originally Posted by Taylor81
Hey guys, i have had my f100 for a few years now and am now looking to upgrade my ignition. Im very confused with all the "recurve" and duraspark II stuff. Its a 1981 f100 300 4.9 carburated. So far engine wise it is stock. I would like the engine to live to its full potential. Ive been looking at New Ignition. Pretty lost. So far i bought the Taylor MSD distributor cap. Im not sure what coil to buy, and if i need a new different ignition module to go with it, if at all. Any suggestions appreciated.
1981 F100 4.9 300 Short Bed single cab 2WD
1981 F100 4.9 300 Short Bed single cab 2WD
Unless yours is failing, you don't need a new ignition system. The Duraspark ignition is good; even the mighty Mustang GT used it in the 1980s. MSD is an ignition system made for racing. The only time you will see a gain by using the MSD is if you are actively racing your truck and spending time above 5500 RPMs. With a full size truck and a stock 4.9, I doubt you are doing that. Since your engine is stock, you don't need a distributor re-curve, either.
If you need to replace any of the ignition parts, try to stick with genuine MOTORCRAFT parts. They cost twice as much but are at least twice as good.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
MSD is only functional below 3, 000 rpms.
It works for drag cars that have locked distributors and run for 10 seconds at a time, at full throttle...
The 4.9 isn't rev happy.
Stock DuraSpark components are long lasting and tailored for this vehicle.
It works for drag cars that have locked distributors and run for 10 seconds at a time, at full throttle...
The 4.9 isn't rev happy.
Stock DuraSpark components are long lasting and tailored for this vehicle.
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
Based on this [see red, above], the MSD on my 1986 4.9L [used because it was available and free when converting from the feedback system] operates ALL the time.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
Not everybody idles around with a 2.75 gear David.
I will say you do get good fuel mileage.
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Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
Jim, with my driving habits, I may actually be over-carbureted with the Carter YF!!!
I just remembered that this thread is about ignition, not carburetion. I apologize for my hijack.
I just remembered that this thread is about ignition, not carburetion. I apologize for my hijack.
Last edited by 1986F150six; Jan 6, 2016 at 03:10 PM. Reason: Apology
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
These trucks had main harnesses to accomodate both DSII and TFI ignitions.
You may have to unwrap some of the harness to find the proper plug to fit the DuraSpark engine harness, but it (with the resistor wire) is in there.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
Do you have the donor harness/coil/distributor from a DSII truck?
Follow your current ignition wiring back to a plug somewhere on the drivers side inner fender.
Unplug it and start working back from there to find the two plugs you need for DuraSpark ignition.
There will be one for the module and one for the coil/oil/water temp.
6th Gear
Joined: Sep 2013
Posts: 6
Likes: 0
From: CT
The ballast resistor and the 2 duraspark plugs aren't there anymore. I hooked up a white wire and a red wire up but I had to disconnect them right away because the starter started to slowly turn when I attached the battery cable. I bought a resistor at radio shack to install tomorrow. I forgot to ask yesterday if I'm supposed to leave the EEC relay and ECM connected. Does anyone out there know what colors the wires are coming out of the firewall on an 86 F150?
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
The resistor is a thick(er) wire in the harnesss.
Someone would have had to go out of their way to hack the harness up in order to remove the plug you need.
What vehicle did you get your Duraspark engine harness from?
Did you get the coil/bracket and distributor too?
Someone would have had to go out of their way to hack the harness up in order to remove the plug you need.
What vehicle did you get your Duraspark engine harness from?
Did you get the coil/bracket and distributor too?