ignition coil issues

ignition coil issues

grnmtn

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north alabama
Vehicle(s)
85 CJ7 258 I6, auto, dana 300
I am a newbie to the site and have have gained a wealth of knowledge from everyone's posts. My Jeep left me stranded this weekend and it turns out the coil just died while I was driving. I replaced the coil with a OEM one and now my idle is about 300 rpm higher and it seems to start faster. Does this sound normal? or was my last coil just putting out less voltage over the last years before it died?
 
?Not sure. The coil is a step up transformer.. It takes the 12-13 V on start up and the 12-13V/ 1.35 Ohm for voltage on Engine RUN. The coil steps up the voltage and applies the higher voltage 20k-45,000 Volts to the spark plug gap.

The coils do get banged up and get internal shorts. Where there is a voltage charge and not GOOD ground to spark to the coil will short out internal. The Voltage jump internal to the coil will put small shorts across the magnet wire by melting the formvar insulation (like shelack coating). The more shorts the less windings and the less the voltage will be put out.

Poor Grounds cause shorts in coil.... and is the reason the spark plug boot should not just be pulled off to see is engine changes. That will cause small shorts in coil. We have all done this but not a good idea.... we have a 30 yr old truck... I am sure the spark plug boot has been pulled off a few times. If a spark plug boot is pulled give it a good ground to engine prior to stating or running.

There is a RESISTANCE reading on the coil that can be done with a multimeter. The fixed winding will have a resistance range.... if lower than the range it has shorts and net effect of having less windings/coil winds or it will have a high resistance and means the coil wire broke and has a short now. Multiple short in the coil is common, esp when you consider some of us have 30 yr old coils.

The resistance range to test your old coil is below. The test procedure can be found in the Jeep Field Service Manual, FSM in the Ignition Section. Also found in the aftermarket manuals.
1.... Primary Resistance Test..
remove coil connector. Measure ohms from the neg to pos terminal on teh coil. Should read 1.13 - 1.23 ohms at 75F degrees
2... Secondary Resistance TEst.....
remove ignition wire from center terminal. Measure ohms from center terminal (coil spark plug wire) and either terminal on the coil. REsistance should measure 7700 - 9300 ohms at 75F





POOR GROUNDS kill the COIL and the spark needs good gounds for the DC Spark to get to the spark plug gap and onto the battery. DC make a complete loop from the battery to the auto and back to battery.

Upgrades I learned from JeepHammer for spark energy & Control:
1..Use premium spark plug wires. I use the MSD premiums or the NApa Drk Navy Beldins.

2..Use copper antizeise on the spark plug threads. Helps with the grounding and many heads are alumium and the plug has steel threads. Aluminum oxidation happens in air, not to mention a 220F engine, not to mention its no in contact with steel. Steel and Alumium a no no with out antizeise. Even for your small engines too.

3..Ground your heads. The spark engergy needs to jump the spark plug gap to light the fire. The strap is a ground from the threads and engine head. The head is often alumium, sits on a steel block, uses a thick gasket and has oil varnish, chemicals, and 30 yrs of corrosion and use. These do not have the best ground. It helps a great deal to ground your head or both heads with a 14 or 12 awg wire.

4..Ground your IGNITION Modual. The ignition modual gets its ground from the Distributor. The distributor is cast alumium, sits on a steel block (issue galvonic corrosion & oil varnsih) and is the GROUND for the Ford DuraSpark Igntion used Jeep in the late 70's and 80's. Poor Ignition Ground will yield poor performance and the weak ground can kill your Jeep DuraSpark Ignition Modual, it will get hot, melt the black potting compound, and you will see black goop oosing out of the Igntion Modual on the drivers fender.
Can ground the Ignition two ways.
A... Ground the Distributor
B... Ground the black wire going to the DuraSpark Ignition Modual. THe modual on drivers fender has two connectors. One has a black wire, that is gound. I cut this wire on the HARNESS SIDE NOT THE IGNITION MODUAL SIDE. We cut the harness side so the mod stays with the jeep wire harness and if the Igntiion Modual needs to be swaped out the aux ground will always be there on the harness side. So cut the Black Gound Wire on the Harness side about 8 in from the connector. Slide on some heat shrink down the wire and solder in a 12-14 awg wire Black and long engough to reach the Neg Battery Terminal or the fire wall for the aux ground. Add some dielectric grease and shrink down the heatshrink to protect the new aux ground for igntion generation.


5.Do the ignition grounds above and you may get more pep, easier starts, better idle.

This would also be done with the TEAMRUSH larger cap & rotar during a tune up . New Spark plug wires and the autolite copper plugs. Do all this and I would say you will be 20% better pep, more rpms, better mileage, better starts, better idle. ON my 78 it was adding a 7th cylinder to my 258 six banger that had all new parts and a complete rebuild...

Big a affect on the 258 and even a bigger affect on the 8 cylinders since they have more rpm range.



Not mentioned in your post... If you moved the distributor or tightened the hold down foot. This might have given you a better igntion ground. FYI.
 
Thanks for the info. I went ahead and did the TeamRush upgrade and its running better than new.
 
Thanks for the info. I went ahead and did the TeamRush upgrade and its running better than new.



grnmtn,

That is great news!

your welcome,

Fred
 
Did you do the full upgrade with a tfi coil? Or just the big cap and rotor button. You wont be dissapointed with the tfi coil and hei ignition module upgrade, you will get alot better spark.

Sent from my DROID2


TFI Coil ????????

About 5 yrs ago I was writing about the TEAMRUSH and I too used the Ford E Coil and the TFI Coil as the same. Jeephammer or JunkYard Genius helped me directly with my updates but also was quick to say there is not such thing as a TFI Coil.

TFI he told me is Thick Film Integrated Circuite.... has nothing to do with the coil.... and was a Complete Ford FLOP.... it failed and did not work well. TFI refers to the igntion modual not the coil.

I am from the electronics field...... and knew TFI was a methold in inks and coatings on a ceramic PCB. The alternative materials put in layers would make the different circuits. Normally PCB, Printed Circuite Boards are made in layers and vias or thru the layer connection points. So TFI circuite boards can be printed on a solder printer cured in a oven and printed again.

WHEN IS THE BEST TIME TO USE THE FORD E COIL???

The ford e coil can be used on both the AMC 6 and 8 cylinger engines. The 258/232 6 banger is a low rev engine with a redline or max rpm of 3500 to 4500 depending on how well the engine is set up and health. The 304/360/401 8 cylinder engines will rev higher in the 5500 rpm range or so.

JeepHammer informs the Ford E Coil will help the 8 cylinder apps with the higher rpms because it can charge and spark quicker than the oil filled cannister. This coil workes better at the higher rpms but not so much at the lower rpms.

The 6 cylinders are lower rev engines..... so we do not see the Ford E coil benefits in the higher rpm ranges. At the lower rpms of a 258 Jeephammer tested the Oil Filled Cannister would do well the stock or the upgraded MSD cannister style. The exception if the I6 is going to have the MSD Multispark Igntion Modual installed then go forward with the Ford E Coil it will drive it just fine.

Another reason... is the Ford Duraspark Ignition Moduals have a few limitations, weaknesses in the 1970s and 80s. The current / new replacement igntion moduals, DurSpark, are weaker and prone to failure. That is why we need good grounds for the modual and the heads/plugs. Weak grounds will over heat the modual because it trying to produce a spark over tooooo much resistance. Weak grounds cause over heating and the potting compount, the black stuff, will melt and seep out of the DuraSpark and on your fender. Once the modual melts the potting compound the Duraspark Modual is suspect/weaker.

If you have a old modual that passes it is GOLD. My orginal duraspark still works, and is a backup ignition on my CJ, back up the MSD Ignition.

The DurSpark Igntion Modual can be tested at Advance Auto for free... tell them to TEST AS FORD IGNITION. Then they will know... if you say it is a jeep they will not know they can test it. Last time I asked at Advance Auto the had a good price on the DuraSpark Moduals, lifetime warranty, and was a good brand too.....

FORD E COIL..... used at the junk yard
Coils can be pulled at the junk yard from the 80s Ford Truck, bronco, cars etc. Often they have mounts that can be taken and used too. Take the wire / connectors to complete your hook up. Junk yard is 3-4$ and new they are like $20. Need a coil and $$$ tight then the junkyard coil is a good app for 6 or 8. If going to buy new then should consider the Ford E Coil or Stock Type Cannister for the 6 bangers and most likely get the E Coil for the 8 cylinders.

This is how I mounted the Ford E Coil in the AMC stock coil location. My invention and have been posting it for a few years.

Ford E coil in stock AMC location
DSCN0807.png


DSCN0803.png

DSCN0804.png



I also did a bit of looking is some info from web on the Ford TFI Igntion Modual.... There is also a nice line dwg with the modual, e coil, wire hook ups, and the full system...

WEB ARTICLE on Ford TFI
http://www.therangerstation.com/tech_library/TFI_Diagnostic.html

Your Ranger/Bronco II is stalling/dieing or sputtering when hot but runs when it cools off. This can be caused by a faulty TFI and the biggest culprits are heat. Another culprit can be a wire grounding out. Problematic TFI's can give off codes 14 (PIP) and 18 (SPOUT).

To start with, here are some links you may find helpful:

TFI Worksheet (Strongly recommend you print this worksheet)



Quick Checks

Technical Service Bulletins (TSBs) pertaining to the ignition system:

  • TFI Stall NO Start - TFI Module Diagnosis and Sealing: This bulletin addresses loss of module ground due to salt and moisture entering a module mounting screw.
  • TFI Engine NO Start/Stall at Idle - New Ignition Module: This TSB talks about an internal short-circuit in some model TFI modules.
  • Driveability Concerns - Moist EEC-IV Connectors: This bulletin asks the tech to check for unsealed EEC-IV connectors and check for moisture or corrosion.
Wiring:

Always check your wiring. Here is a picture of SPOUT (Spark Output signal) wire that was grounding out.


TFI_spoutwire.jpg


The yellow spark output signal wire is without a section of insulation. This section happens to run through a shield ground that provided a convenient ground source for the SPOUT signal. Just the right bump in the road or vibration from the engine would provide a path of lesser resistance for the SPOUT signal, killing the coil trigger.


TFI_connections.jpg


This is where the TFI Modile plugs in to the distributor to get the PIP signal. Notice the defective insulation.

Heat Is Your Enemy!:

The top three leads (for PIP signal) can lose continuity with the back plate (ground) on the module when the unit is hot. You should consider a remote mounted TFI. If your TFI is failing from heat, it can give off computer codes 14 (PIP) and 18 (SPOUT).

General Information

The TFI-IV distributor ignition system consists of the following components:

  • Thick Film Ignition (TFI) modules
  • Distributor
  • Camshaft Position (CMP) sensor
  • Ignition coil
The distributor ignition system designed by Ford has two distinct configurations. The first configuration is known as the distributor mounted system, because the TFI is mounted directly on the distributor housing. The second configuration is known as a remote mount system, since the TFI is mounted on the engine or front fender apron.

The distributor used by this system is sealed and houses the CMP sensor. The distributor does not utilize vacuum or centrifugal advance mechanisms; the ignition timing is automatically controlled by the Powertrain Control Module (PCM) and the TFI.

Ford calls this electronic ignition the Thick Film Integrated-IV (TFI-IV) ignition system. The TFI module is also known as the Ignition Control Module (ICM) which reports engine position and rpm to the PCM. The PCM then determines the proper spark timing and advance, and returns a reference signal to tell the TFI module to switch the coil, thereby by creating a spark. The PCM used on these vehicles is referred to by Ford as the Electronic Engine Control-IV (EEC-IV) module.


TFI_ignitiondiagram.gif


System Operation
 
Last edited:
few more months and we will have some more tech articles.:chug:

grnmtn,

Not sure yet... but the grounds I mention for the igntion modual and the heads and even the copper antizeise ARE VERY IMPORTANT. If you did not do them... great to do .... and they help LOTS

Regards,

Fred
 
I used a new OEM cannister coil since I had one in the garage and also added the additional ground wire on the ignition module.
 
i run a msd street fire (there econo brand which has a built in rev limiter) and a msd blaster 3 coil and love it. i also have the teamrush done to it.
 
Last edited:
I used a new OEM cannister coil since I had one in the garage and also added the additional ground wire on the ignition module.


Very good. Thanks for the info on what was done.

I also suggest STRONGLY Ground your engine head. I used the coil mount stud for the head ground, and there is a emply threaded hole just behind the distributor/coil area. I made a short jumper 3" or so and also used this emply threaded hole in the block as a aux ground stud location. I ran the neg batter to this empty threaded hole, ground the firewall, ground the dash, ground the head, and ran a ground to the frame. All grounds were 12 awg black insulation and the battery ground and frame ground were 4 - 6 awg.

There is more gounding to do but this will help a great deal.

CJ need a lot of gounding work... I will try to get a write up posted on the aux grounds and correcting many issues that are electrical in nature. Helps ignion, lights, starter, the this does not work when this is on, it does not happen all the time type comments.

You guys get it we need grounds.

Fred
 


Gert,

Thanks for the thank you, and the beer. Maybe next winter this snow bird can have that beer with you if I visit some of friends in TX. Always nice to break up our long winter.

We are about to get 14" of heavy wet snow.

Glad you like the info...
I think the TEAMRUSH with proper coil, premium plug wires, copper antisieze, dielectric grease, and aux grounds is the VERY BEST UPDATE we can do for our Jeep CJs.

TEAMRUSH ++ stuff......
Just the gas mileage benefit of 5-8 mpg and grin factor make the tune up parts free.


Thanks,

Fred
 
HEAD GROUND

In the Ford E Coil mounted picture the threaded hole ground location can be seen to the left of the coil. IT DOES NOT show the short 3" jumper from the threaded ground hole to the Coil Mount Bolt. It is there now... Any confusion let me know I will look for the new pic.

Fred
 
TFI Coil ????????

About 5 yrs ago I was writing about the TEAMRUSH and I too used the Ford E Coil and the TFI Coil as the same. Jeephammer or JunkYard Genius helped me directly with my updates but also was quick to say there is not such thing as a TFI Coil.

TFI he told me is Thick Film Integrated Circuite.... has nothing to do with the coil.... and was a Complete Ford FLOP.... it failed and did not work well. TFI refers to the igntion modual not the coil.

I am from the electronics field...... and knew TFI was a methold in inks and coatings on a ceramic PCB. The alternative materials put in layers would make the different circuits. Normally PCB, Printed Circuite Boards are made in layers and vias or thru the layer connection points. So TFI circuite boards can be printed on a solder printer cured in a oven and printed again.

WHEN IS THE BEST TIME TO USE THE FORD E COIL???

The ford e coil can be used on both the AMC 6 and 8 cylinger engines. The 258/232 6 banger is a low rev engine with a redline or max rpm of 3500 to 4500 depending on how well the engine is set up and health. The 304/360/401 8 cylinder engines will rev higher in the 5500 rpm range or so.

JeepHammer informs the Ford E Coil will help the 8 cylinder apps with the higher rpms because it can charge and spark quicker than the oil filled cannister. This coil workes better at the higher rpms but not so much at the lower rpms.

The 6 cylinders are lower rev engines..... so we do not see the Ford E coil benefits in the higher rpm ranges. At the lower rpms of a 258 Jeephammer tested the Oil Filled Cannister would do well the stock or the upgraded MSD cannister style. The exception if the I6 is going to have the MSD Multispark Igntion Modual installed then go forward with the Ford E Coil it will drive it just fine.

Another reason... is the Ford Duraspark Ignition Moduals have a few limitations, weaknesses in the 1970s and 80s. The current / new replacement igntion moduals, DurSpark, are weaker and prone to failure. That is why we need good grounds for the modual and the heads/plugs. Weak grounds will over heat the modual because it trying to produce a spark over tooooo much resistance. Weak grounds cause over heating and the potting compount, the black stuff, will melt and seep out of the DuraSpark and on your fender. Once the modual melts the potting compound the Duraspark Modual is suspect/weaker.

If you have a old modual that passes it is GOLD. My orginal duraspark still works, and is a backup ignition on my CJ, back up the MSD Ignition.

The DurSpark Igntion Modual can be tested at Advance Auto for free... tell them to TEST AS FORD IGNITION. Then they will know... if you say it is a jeep they will not know they can test it. Last time I asked at Advance Auto the had a good price on the DuraSpark Moduals, lifetime warranty, and was a good brand too.....

FORD E COIL..... used at the junk yard
Coils can be pulled at the junk yard from the 80s Ford Truck, bronco, cars etc. Often they have mounts that can be taken and used too. Take the wire / connectors to complete your hook up. Junk yard is 3-4$ and new they are like $20. Need a coil and $$$ tight then the junkyard coil is a good app for 6 or 8. If going to buy new then should consider the Ford E Coil or Stock Type Cannister for the 6 bangers and most likely get the E Coil for the 8 cylinders.

This is how I mounted the Ford E Coil in the AMC stock coil location. My invention and have been posting it for a few years.

Ford E coil in stock AMC location
DSCN0807.png


DSCN0803.png

DSCN0804.png



I also did a bit of looking is some info from web on the Ford TFI Igntion Modual.... There is also a nice line dwg with the modual, e coil, wire hook ups, and the full system...

WEB ARTICLE on Ford TFI
Ford Ranger/Bronco II TFI Ignition Diagnostics

Your Ranger/Bronco II is stalling/dieing or sputtering when hot but runs when it cools off. This can be caused by a faulty TFI and the biggest culprits are heat. Another culprit can be a wire grounding out. Problematic TFI's can give off codes 14 (PIP) and 18 (SPOUT).

To start with, here are some links you may find helpful:

TFI Worksheet (Strongly recommend you print this worksheet)



Quick Checks

Technical Service Bulletins (TSBs) pertaining to the ignition system:

  • TFI Stall NO Start - TFI Module Diagnosis and Sealing: This bulletin addresses loss of module ground due to salt and moisture entering a module mounting screw.
  • TFI Engine NO Start/Stall at Idle - New Ignition Module: This TSB talks about an internal short-circuit in some model TFI modules.
  • Driveability Concerns - Moist EEC-IV Connectors: This bulletin asks the tech to check for unsealed EEC-IV connectors and check for moisture or corrosion.
Wiring:

Always check your wiring. Here is a picture of SPOUT (Spark Output signal) wire that was grounding out.


TFI_spoutwire.jpg


The yellow spark output signal wire is without a section of insulation. This section happens to run through a shield ground that provided a convenient ground source for the SPOUT signal. Just the right bump in the road or vibration from the engine would provide a path of lesser resistance for the SPOUT signal, killing the coil trigger.


TFI_connections.jpg


This is where the TFI Modile plugs in to the distributor to get the PIP signal. Notice the defective insulation.

Heat Is Your Enemy!:

The top three leads (for PIP signal) can lose continuity with the back plate (ground) on the module when the unit is hot. You should consider a remote mounted TFI. If your TFI is failing from heat, it can give off computer codes 14 (PIP) and 18 (SPOUT).

General Information

The TFI-IV distributor ignition system consists of the following components:

  • Thick Film Ignition (TFI) modules
  • Distributor
  • Camshaft Position (CMP) sensor
  • Ignition coil
The distributor ignition system designed by Ford has two distinct configurations. The first configuration is known as the distributor mounted system, because the TFI is mounted directly on the distributor housing. The second configuration is known as a remote mount system, since the TFI is mounted on the engine or front fender apron.

The distributor used by this system is sealed and houses the CMP sensor. The distributor does not utilize vacuum or centrifugal advance mechanisms; the ignition timing is automatically controlled by the Powertrain Control Module (PCM) and the TFI.

Ford calls this electronic ignition the Thick Film Integrated-IV (TFI-IV) ignition system. The TFI module is also known as the Ignition Control Module (ICM) which reports engine position and rpm to the PCM. The PCM then determines the proper spark timing and advance, and returns a reference signal to tell the TFI module to switch the coil, thereby by creating a spark. The PCM used on these vehicles is referred to by Ford as the Electronic Engine Control-IV (EEC-IV) module.


TFI_ignitiondiagram.gif


System Operation
sorry, my mistake i called it the wrong thing, e-coil i got it.
 
Cheapjeep85,

Sorry would not have said anything about it... but seems most times I have seen TeamRush on this forum .... there is the use of TFI Coil.

Heck... as said above.... I used the Ford E Coil and TFI Coil interchangable as the same coil and similar words INCORRECTLY TOO. I was shown the way too, still have some pretty good posts were I am using the wrong verbage....=TFI. No such thing as a TFI Coil.

The truth TFI refers to the Thick Film Integrated circuite to make a ceramic pcb with layers of conductive inks and films.


Fred
 
If these broken,the engine will not function and of course the car won't start. It is advised to replace it immediately. You just need handy materials like screwdrivers, wrenches, tray for screws,needle nose pliers. It's just easy and affordable! You don't need mechanic to fix your car. You can do it on your own. :)
 
Do you know why a new tach reads 1000rpm over the old one? Also, do I connect the oil pressure gauge to the coil? They are Morris gauges but when I connected the oil pressure sender unit to the gauge there was no reading, what can I do?
 

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