E-core Ignition Coils and a Couple Other Ignition Questions

[thundley57]

I'm hoping some of you ignition experts can answer these questions:

I have the Team Rush ignition upgrade installed on my AMC 258 i6 / 4.2l ci engine which was a kit I bought from CRTPerformance and installed almost 2 years ago. The kit included the larger Ford dist cap/rotor/plug wires and an e-core coil. Several months ago I bypassed the resistor wire to the + side of the coil to bring 12V to the coil 100% of the time and not only during starting. CRTPerformance told me their coil could handle full time 12V and it was my understanding that the reason for the resistor wire in the 1st place was to protect the stock coil. Is this true? Yesterday my coil failed and I'm not sure if it was because I'm running full time 12V to it or not. I installed my spare e-core coil and noticed with the engine running the coil is very hot to the touch. You can keep your hand on it for maybe 5 seconds before it gets uncomfortably hot.

Is the fact that I'm running full time 12V to the coil putting any undue stress on my distributor components such as the pick up coil?

I'm considering replacing the e-core coil with the MSD Blaster high vibration coil (part #8222) and the installation instructions on their website state that a resistor must be installed if you have the stock, points style ignition. My distributor and ignition module are stock but I do not have points so am I good to install without the resistor? Have any of you bypassed the resistor wire as well?

One other question; I have a black wire coming out of the wiring harness near the starter solenoid that has a connector on it just like the red and blue wires that are connected to the ignition and start connectors on the solenoid (see attached picture). The wire is not connected to anything. Does anybody know what this wire was intended for?



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[DaveMueller]

One other question; I have a black wire coming out of the wiring harness near the starter solenoid that has a connector on it just like the red and blue wires that are connected to the ignition and start connectors on the solenoid (see attached picture). The wire is not connected to anything. Does anybody know what this wire was intended for?
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Could be the oil pressure sender, but I thought that was a blue wire. I can't think of anything else near the starter that would have a stud for an output signal.

Dave

 

[Torxhead]

I put in an e-core coil in about 12 or so years ago, so far no problems. Although I still have the resistor wire in, I did shorten it as it was quite long, I get 9 volts at the coil because of that. 12 volts might be tough on the less expensive ignition control modules. That black wire near the relay is probably for the neutral safety switch for the automatic trannys.

 

[thundley57]

I put in an e-core coil in about 12 or so years ago, so far no problems. Although I still have the resistor wire in, I did shorten it as it was quite long, I get 9 volts at the coil because of that. 12 volts might be tough on the less expensive ignition control modules. That black wire near the relay is probably for the neutral safety switch for the automatic trannys.

Thanks Torxhead. So am I correct in saying that the resistor wire is to protect the coil and not the distributor components?


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[Torxhead]

I am sure that all the Motorcraft ignitions for the CJs have the resistor wire. I thought that the e-core coil could take a full 12 volts, so much for that thinking. You might even want to consider the oem style coil as a replacement. I take it you have that diode installed inline on that resistor wire?

 

[Scorzany]

I read somewhere that the third wire is for a tachometer if you have one. Otherwise its just there. I have the third wire as well but not connected and I do not have a tachometer. So maybe that's what it's for? /shrug

I got the MSD Blaster high vibration coil when I did the Team Rush upgrade. Figured the Jeep bounces around so much it was worth a few extra bucks.

This is what I had found about the resistor wire to the coil:

Post #4

"There is a resistor in the circuit to limit voltage to the coil except during cranking.
If you ran 12VDC to the coil all the time you would either fry the coil or the ECM.
Voltage in the run position should be between 5.5 and 6.6 VDC"

Voltage to the coil ? - JeepForum.com

 

[thundley57]

I am sure that all the Motorcraft ignitions for the CJs have the resistor wire. I thought that the e-core coil could take a full 12 volts, so much for that thinking. You might even want to consider the oem style coil as a replacement. I take it you have that diode installed inline on that resistor wire?

Diode? Is that a stock item? I've had the entire resistor wire exposed and did not notice a diode anywhere. What is its purpose?

 

[Torxhead]

In post #1 you state that you have removed the resistor wire, I assumed that you have replaced it with a standard wire. Did you just remove it? I have read about replacing it with a standard wire with a diode to prevent backfeeding from the alternator.

 

[thundley57]

In post #1 you state that you have removed the resistor wire, I assumed that you have replaced it with a standard wire. Did you just remove it?

No I left the existing resistor wire in place and simply soldered in a parallel wire.


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[Torxhead]

So just how do you plan to fix this? The coil does seem to be getting too much voltage though.

 

[thundley57]

So just how do you plan to fix this? The coil does seem to be getting too much voltage though.

Well assuming that is true I will remove the parallel wire and go back to the resistor wire only. According to CRTPerformance their e-core coil is designed to withstand a constant 12V as is the MSD blaster coil so I'm still not convinced that the coil failure was related to the constant 12V or something else. What was the diode you were talking about?


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[Torxhead]

Since you did get another coil in a kit, it could have been an inexpensive one designed to run at 6 volts regardless of what they said. MSD of course is a quality product. I use the Echlin brand from N.A.P.A. That diode I was mentioning was from reading some of the CJ posts of the well known Jeep guru Team Rush. His method was to replace the resistor wire with a conventional wire and add a diode to prevent backfeeding from the alternator to the coil. This was to prevent engine run on after the ignition was shut off, I was surprised that you made no mention of having that issue.

 

[thundley57]

Since you did get another coil in a kit, it could have been an inexpensive one designed to run at 6 volts regardless of what they said. MSD of course is a quality product. I use the Echlin brand from N.A.P.A. That diode I was mentioning was from reading some of the CJ posts of the well known Jeep guru Team Rush. His method was to replace the resistor wire with a conventional wire and add a diode to prevent backfeeding from the alternator to the coil. This was to prevent engine run on after the ignition was shut off, I was surprised that you made no mention of having that issue.

I don't ever recall reading about the diode but at any rate, with the Howell TBI the ECM cuts fuel immediately upon ignition switch cutoff so the engine won't diesel, works well. Just wish I could get a definite answer to whether or not I can run continual 12V to a coil that is designed for this but I guess for now I'll go back to using the resistor wire to play it safe. You mentioned you've had an e-core type coil for many years, mind sharing which one you're running?

 

[Lumpy Grits]

IIRC that 3rd wire is a starter interrupt for the auto tranny.

The MSD coil is built to 'run' with 12vdc.
LG

 

[thundley57]

IIRC that 3rd wire is a starter interrupt for the auto tranny.



The MSD coil is built to 'run' with 12vdc.

LG

Thanks LG! So running constant 12V to the MSD coil won't burn out the distributor pickup coil or the ECM?


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[Lumpy Grits]

Hasn't on mine in the 12-15yrs I have run one of the older analog MSD igns.
The resistance wire is located in the loom, that is on the firewall. It's crimped and looks like wrapped in some type of heat resistant tape.
Just remove that r'wire and solder in a 'splice'.
You should call MSD and confirm with them.
LG

 

[thundley57]

Hasn't on mine in the 12-15yrs I have run one of the older analog MSD igns.
The resistance wire is located in the loom, that is on the firewall. It's crimped and looks like wrapped in some type of heat resistant tape.
Just remove that r'wire and solder in a 'splice'.
You should call MSD and confirm with them.
LG

Are you running with the factory distributor LG? I see that your Jeep is an 85 so I'm assuming it has an ECM.

 

[Lumpy Grits]

Yup, on OEM 'dizzy'.

LG

 

[yellow85cj]

The black wire is for the Neutral Safety Switch (NSS) . If you look at an automatic solenoid (yes there is such a thing) you will see another stud. It is for the connector you have pictured. If the Transmission is not in park or neutral it will ground the solenoid and not allow it to power the starter.

In theory you could use an automatic solenoid on a manual Transmission as a "make it harder to steal " switch. Put a toggle switch in that would ground the solenoid and would not allow the engine to start.

Seem to remember that on a 70's manual Transmission car I had, wouldn't start if the clutch wasn't depressed. Same thing.

 

[thundley57]

Found this post on the Jeep Forum by JeepHammer, I'm thinking I need to re-hook up my resistor wire since I do have the Duralast ignition module:

Quote:
Originally Posted by BioTex View Post
I swapped my points distributor (73 AMC 258 i6 / 4.2l ) with a newer electronic distributor.

I still have the ballast resistor hooked up. Do I still need it?


You didn't really tell us WHICH electronic distributor you are using...

The distributor doesn't care if you have a resistor or not.
It's the ignition module that will usually suffer if you need one and don't have it,

Or the spark energy will suffer if you have one and don't need it...
----------------------

The common Jeep ignition module that MUST have a 1.35 to 1.5 Ohm resistor is the Jeep/Ford/DuraSpark module used in all factory ignitions from '78 to '86.

The DuraSpark module simply won't live without that resistor before the coil.

GM HEI style modules and the aftermarket CDI modules don't need a resistor, and you will burn the ignition up if you use a resistor with a CDI module in the coil circuit.