Need help with tfi upgrade and nutter bypass

[onthebus13]

I updated my jeep with a new motercraft carb, did the nutter bypass and upgraded to a Tfi coil (plugs,wires,cap,roter) . The jeep runs great but i'm having an intermittent problem. The engine will just die at times . The power to the coil is interupted and just cuts out. I have not replaced the ignition control module yet,but I suspect it maybe overheating as it only takes 4 minutes and the jeep will start right back up. With the high output coil should i replace the module with a stock jeep ignition control module ? Or any ideas on what the problem might be? Any help would be great,thanks.

 

[expertshooter22]

you might want to check into putting a ballast resistor in it, it will nock down the power coming in to the coil to keep it from heating up and shutting you down. I just did the nutter bypass on my 85 cj7 and so far haven't had to put a ballast resistor in it but i may need to soon. I don't have the info in front of me but i know that there are a couple of really good other forums that talk about the ballast resistor, some need it, some don't. and it is a 6 dollar part

 

[onthebus13]

I upgraded with the "juice box" coil, the instructions didn't call for reusing this part but I recently added a wire from the + side of the coil to a part called a ignition capacitor( i included a pic) and reconnected it to the old coil bracket . so far I've had no stalls, but i have herd of the ballast resister I'm just not sure what that is, can anybody tell me if a ignition capacitor and a ballast resister are the same thing?

 

[defmornahan]

so far I've had no stalls, but i have herd of the ballast resister I'm just not sure what that is, can anybody tell me if a ignition capacitor and a ballast resister are the same thing?

They are definitely not. A capacitor is basically two metal plates close together that store charge. It can dampen variations in current and do many other things. A resistor simply resists current flow, so that at a given voltage a circuit will pass less current.

 

[buckshot500]

The resistance wire in question, is in place on all 87-90 YJ's
It's highlighted in yellow on this diagram & lives inside the big harness loom going across the back firewall of the engine bay. It may or may not say "do not cut" on the insulation, but it should look different from the rest of the wires in there.

 

[onthebus13]

I'm still having stalls, so I'm looking into a ballast resister. I did locate and check the resistance wire and it was fine,no burn marks or broken connections. I did notice the writing on the line saying do not cut. Do i need to remove the resistance line and replace it with a ballast resistor? How should I install a ballast resistor? thanks for the help.

 

[buckshot500]

I'm still having stalls, so I'm looking into a ballast resister. I did locate and check the resistance wire and it was fine,no burn marks or broken connections. I did notice the writing on the line saying do not cut. Do i need to remove the resistance line and replace it with a ballast resistor? How should I install a ballast resistor? thanks for the help.

If you have that wire, you shouldn't need a ballast resistor!

I can't remember exactly, but there should be a lowered voltage (8 to 11 volts IIRC) at one of the coil terminals.( may be the (+) side) The answer can be found at jeepsunlimited.com

You'll need to register to do a proper board search there. The answer will come from one of three members. John Strenk, mbalbritton, or JunkYardGenius.

Do a board search for resistor wire. The page with all the threads will come up, & you want ones that are designated from the CJ forum.

The thing is, the CJ needs the wire from Napa as it wasn't in the CJ harness. Once I went through many E-conversations I was able to understand the schematic I posted in this thread. I highlighted the wire with yellow & mbalbritton agreed it was the one. That wire appears in the chilton's drawings for all 4.2L 87-90 YJ's

The reason it's needed is the ignition module will fry with a higher output coil, such as the E-core coil from junkyard escorts. (I run one of these, & it works great $5.00)

Also your problem could just be a bad module. If you can find an original "Ford Dura-spark" box at the junkyard, it's gonna be way more reliable than any box you can buy new. Especially a new one from a big box parts house like autozone.

Re-check all your Nutter connections too, make doubly sure they are tight.

EDIT; look through these links;
Junk Yard Genius.com 'Stealth HEI Page
Ballast REsistor and TFI coil...
Frying ignition modules - Page 2 - JeepForum.com

I think that one of these shows how to use an HEI ignition module inside a gutted duraspark box. Not saying it's the way to go, but it is an option & can be used as a backup.

 

[Keith__C]

FORGET all you have heard about a Ballast resistor the Ford TFI Ignition coil REQUIRES a +12V input voltage. My Ford has a 14.2 signal at the coil while its running and has never had voltage related issues. All that you will accomplish by putting a ballast in your system will be to effectively spend $$$ to put a coil with less spark output than stock in it. Put a Chevy HEI Module in place of the Duraspark box, its EASY and simple.

Step 1 Take an old Duraspark box and cut the pigtails off.

Step 2 Get a *"PERFORMANCE"* 4 pin HEI Module--Notice PERFORMANCE--Stock replacement versions are JUNK!!! Get an old CPU heatsink from a dead computer or just buy one I found AMD Socket A heatsinks work PERFECT for this.

Step 3. Crimp female spade connectors to the wires from the pigtails.
Orange Goes to W
Purple foes to G
Green Goes to C
Red Goes to B.
Black Goes to Ground--you must also make sure the HEI module is grounded, I've attached a dedicated ground to one of the mounting screwes just to make sure it has a solid ground.
White is not used, You can cut it off at the plug if you want

Step 4: Plug it in in GO

Step 5: Tell everyone who talks about a Ballast resistor being required or used with ANY kind of Electronic Ignition they are Wasting money and degrading the systems overall integrity. nothing less than FULL +12V is required at the Coil. If your system somehow magically runs better with a ballast its a good sign your module is on its last legs anyways.

 

[onthebus13]

At this point I realize the ignition module is going out, so i''ve decided to replace it with a gm 4 pin module from summit ( proform, proformence control mod.http://www.summittruck.com/parts/PRO-66944C/.) Ive read all about how to do the install ,but my question is? will the gm module work for my 89 yj ? The instructions on the junkyard genius didn't give a vehicle specific year that his moods will work for? also would it hurt anything if i hooked a diode up to the white wire just in case,or can i disconnect it and not use it?I have the ford tfi upgraded coil,cap ,and roter .Now i just need a module that can handle the tfi upgrade.Junk Yard Genius.com 'Stealth HEI Page

 

[Keith__C]

You don't use the white wire, just cap it off so it isn't exposed. I've attached 2 pics of my setup. Where I've screwed the module to the heatsink the black wire is from the duraspark plug, the red wire is a ground wire I've attached to the firewall, yeah its red, yeah its a ground. The white wire I cut off completely you do not need it. This mod is good for ANY year that uses a Duraspark ignition module.

 

[onthebus13]

I finely finished replacing my dura spark module with a gm ignition module , i used accels performance module. I was going over a wiring diagram that I got when I did the TFI upgrade and I noticed that the + side of the coil was replaced with a 10 gauge wire. So I fugered it could'nt hurt to use a bigger gauge wire for the coil and I replaced the + side wire with a 10 gauge all the way up to the resistence wire. This might have been the cause for the interment stalls I was having ,as it would stall and 30 seconds latter it would fire right back up. After I finished with the swap it started right up and ran great, Ive only driven it about 35 miles but no stalls ,yet. I also have'nt noticed any dragging on the starter or any trouble with hot start. I did remount the old module and I plain on using it for a back up . Thanks so much for all the help on this issue, and a special thanks to Keith C for all your help and for the links to the junk yard genius .