Duraspark Wiring Dilema

Low Tech · Jun 12, 2008

I'd like to do the conversion from TFI ignition and carb. to Duraspark. I'm not having any luck finding a wiring harness for the 2.8L. The salvage yards around here crush older vehicles. Any suggestions. Thanks!

skippy · Jun 12, 2008

Low Tech said:
I'd like to do the conversion from TFI ignition and carb. to Duraspark. I'm not having any luck finding a wiring harness for the 2.8L. The salvage yards around here crush older vehicles. Any suggestions. Thanks!

i used new connectors from napa,added wire to make them long enough and black plastic wire loom to wrap em,making them look more proffesional.

1.napa#echec127,1 each
2.napa#echec72,1 each

hope this helps.

Low Tech · Jun 12, 2008

Duraspark Harness Fabricator

Thanks for the help. So you basically made your own ignition harness, right? Then bought distributor, dist. cap and adapter, rotor, ignition module, and coil new?

Did you swap the carb. too?

igiveup · Jun 12, 2008

Hello

I got all of mine from the junk yard with the parts for my duraspark conversion. Made all of my own harness. found mine in a 78-79 2.8l capri. I should of grabbed the carb but didnt. Still it runs better than before.

igiveup

Low Tech · Jun 13, 2008

Duraspark Ballast Resistor

Great and thanks for the reply.

One more question. I found a Duraspark ignition schematic wiring diagram @ Autozone.com>Repair Info>(enter vehicle type at some point)>Engine Electrical>Duraspark II Ignition System>Figure 3.

In that schematic it shows a "ballast resistor" between the ign. switch "Run" terminal and the "Bat" terminal on the coil. No Resistor type or value info is given. Did you put a resistor in your wiring harness? If so, what type resistor?

Thanks a Gazillion.

small ranger · Jun 13, 2008

I did not use a ballast resistor and mine works fine. I just used 3 diffrent colored wires and the female spade teminals ends and made my one harness in about 5 minutes. I highly recomend a holly 350 cfm carb, becaust the motorcraft 2150 will run a little rich without the computer i think, but ask someone else to be sure.

85_Ranger4x4 · Jun 13, 2008

I got the harness of of a 1980 400 we had sitting around, got the module from a junkyard. I am using the stock coil so I didn't need a resistor.

The stock 1250 runs rich, but they did make non computer 1250's that work perfect.

skippy · Jun 13, 2008

Low Tech said:
Thanks for the help. So you basically made your own ignition harness, right? Then bought distributor, dist. cap and adapter, rotor, ignition module, and coil new?

Did you swap the carb. too?

yes i did,holley 350 cfm 2 barrel.dropped right on.

Forcus · Jun 16, 2008

You should check out the 2.8L forum. There is a ton of duraspark info there. Also check out the tech library as it has diagrams.

You can get everything from the junkyard or from various vendors (eBay, NAPA, Autozone, etc). At a minimum you need a non-TFI distributor, control module, non-feedback computer, and the requisite connectors.

I believe the resistor wire comes in to play with the canister-style non-TFI coil. If I recall correctly there is 12V to the distributor when starting which drops down to 9-10V during operation. I assume that is to increase longevity as I've seen some folks on here have found the coils to be sizzling hot if they didn't drop the voltage. I've also ready that the TFI coil is OK with 12V so there may be no need to add a resistor wire if you already have the TFI coil.

I was curious if you could make the TFI distributor work without the computer. The short answer is yes, but you will not have any timing advance. This is OK if it's just a farm truck or offroad beast but not so good for highway mileage.

FYI, I've found the distributors on average are $65 with a $15 core, but come bare, so you'll need a cap ($10ish), collar / adapter ($10ish), rotor ($3ish). Coil connectors are $6ish (won't need if you keep the TFI coil), control modules are $20-$70, and wiring you can reuse from your harness.

85_Ranger4x4 · Jun 16, 2008

Forcus said:
You should check out the 2.8L forum. There is a ton of duraspark info there. Also check out the tech library as it has diagrams.

You can get everything from the junkyard or from various vendors (eBay, NAPA, Autozone, etc). At a minimum you need a non-TFI distributor, control module, non-feedback computer, and the requisite connectors.

I believe the resistor wire comes in to play with the canister-style non-TFI coil. If I recall correctly there is 12V to the distributor when starting which drops down to 9-10V during operation. I assume that is to increase longevity as I've seen some folks on here have found the coils to be sizzling hot if they didn't drop the voltage. I've also ready that the TFI coil is OK with 12V so there may be no need to add a resistor wire if you already have the TFI coil.

I was curious if you could make the TFI distributor work without the computer. The short answer is yes, but you will not have any timing advance. This is OK if it's just a farm truck or offroad beast but not so good for highway mileage.

The resistor is a ceramic resistor, they are pretty common and just have a spade connector at each end with a bolt hole to secure it somewhere. I didn't bother with one with the stock coil. I figure the coil shouldn't really care which distributer it is hooked up to anyway...

Somehow my truck has ran with no/little computer input for the 7 years I had before I durasparked it... I would not recomend it. Major blowby, constintly black oil, oil smells like gas... any way you cut it not a good thing. I would have done it sooner, but I kept thinking "it isn't going to keep running that much longer anyway", until I decided that the stupid thing wasn't going to kick the bucket anytime soon and deserved it. That was with the stock distributer and carburator. If you have to do one or the other I could jump on the carb first, only thing I really gained with the dist was a smoother idle (original distributer was just about shot) and I still get 10mpg. It might get driven 20 miles per week on a hard week, just enough to keep the spiders and mice from getting too comfy until I get ready to do a heart transplant.

One nice thing is if you decide to swap in a V-8, your ignition is already wired. :icon_thumby:

laclabb · Aug 25, 2008

skippy said:
i used new connectors from napa,added wire to make them long enough and black plastic wire loom to wrap em,making them look more proffesional.

1.napa#echec127,1 each
2.napa#echec72,1 each

hope this helps.

How much would it usually cost me with these 2 new connectors? Was it hard? Actually, I don't have any plans to do it myself but want to try it though.
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CRAZ28 · Oct 9, 2008

making your own harness is cake, just get 3 different color wires and the connecters from NAPA and connect up

lil red · Oct 30, 2008

ya, making stuff like that is easy
o and craz28, nice sig

CRAZ28 · Oct 31, 2008

o yea

ifergusson · Nov 3, 2008

When I did the Duraspark conversion I used a GM HEI module instead of a Duraspark module, the wiring is easier, you can use the stock TFI coil and you don't need a resistor.Here's a link to some info if you are interested http://www.carbdford.com/tech/HEI/hei.htm

Duraspark Wiring Dilema

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