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Author Topic: Best New ICM  (Read 5830 times)

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Offline George Mann

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Best New ICM
« on: September 05, 2012, 05:29:11 PM »
Anybody know who makes a dependable ICM these days (DuraSpark II)?
1985 Eagle Wagon

Offline carnuck

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Re: Best New ICM
« Reply #1 on: September 06, 2012, 03:20:59 AM »
Wells seem pretty good, but if your ground wire in the harness from the dist to fender is toast, you'll go through a bunch of any brand. (when the ground from battery to fender goes bad, the power ALL tries to pass through that little wire for headlights, etc)
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline George Mann

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Re: Best New ICM
« Reply #2 on: September 07, 2012, 01:57:55 AM »
Wells seem pretty good, but if your ground wire in the harness from the dist to fender is toast, you'll go through a bunch of any brand. (when the ground from battery to fender goes bad, the power ALL tries to pass through that little wire for headlights, etc)

I don't know about you, but my battery grounds to my engine block.
1985 Eagle Wagon

Offline George Mann

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Re: Best New ICM
« Reply #3 on: September 07, 2012, 02:05:32 AM »
1985 Eagle Wagon

Offline carnuck

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Re: Best New ICM
« Reply #4 on: September 07, 2012, 04:41:59 PM »
Wells seem pretty good, but if your ground wire in the harness from the dist to fender is toast, you'll go through a bunch of any brand. (when the ground from battery to fender goes bad, the power ALL tries to pass through that little wire for headlights, etc)

I don't know about you, but my battery grounds to my engine block.

Yes it does, BUT if you don't also have a ground to the fenders, then ALL the power items (fan, windows, lights, etc) will try to ground backwards through that little ground wire and overheat it and the wiring. Fopr electrics to work, you need power and ground. Power is fleeting (turn on/off) but the ground has to be permanent!
   Otherwise lights are dim, etc because the power tries to flow through the engine bearings, driveshaft, diff, springs, etc back to the battery.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline George Mann

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Re: Best New ICM
« Reply #5 on: September 07, 2012, 05:10:00 PM »

Yes it does, BUT if you don't also have a ground to the fenders, then ALL the power items (fan, windows, lights, etc) will try to ground backwards through that little ground wire and overheat it and the wiring. Fopr electrics to work, you need power and ground. Power is fleeting (turn on/off) but the ground has to be permanent!
   Otherwise lights are dim, etc because the power tries to flow through the engine bearings, driveshaft, diff, springs, etc back to the battery.

Yes, I understand electrical theory better than most. I am both an engineer, as well as a mechanic.

My point is that normally cars ground both their battery and ICM (via distributor) thru the engine block, which in turn grounds to the chassis thru a ground strap.

It wouldn't hurt to also ground the ICM directly to the chassis.

1985 Eagle Wagon

Offline carnuck

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Re: Best New ICM
« Reply #6 on: September 08, 2012, 01:46:17 AM »

Yes it does, BUT if you don't also have a ground to the fenders, then ALL the power items (fan, windows, lights, etc) will try to ground backwards through that little ground wire and overheat it and the wiring. Fopr electrics to work, you need power and ground. Power is fleeting (turn on/off) but the ground has to be permanent!
   Otherwise lights are dim, etc because the power tries to flow through the engine bearings, driveshaft, diff, springs, etc back to the battery.

Yes, I understand electrical theory better than most. I am both an engineer, as well as a mechanic.

My point is that normally cars ground both their battery and ICM (via distributor) thru the engine block, which in turn grounds to the chassis thru a ground strap.

It wouldn't hurt to also ground the ICM directly to the chassis.



What I was trying to point out is the ground strap is often forgotten when replacing motor, motor mounts, etc and the ground in the harness from the dist to the fender mounted box gets melted because of it.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline captspillane

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Re: Best New ICM
« Reply #7 on: September 08, 2012, 01:26:00 PM »
My ground strap broke and welded itself to the body, igniting the first of three fires I had in my SX4 over the years. Those ground straps should not be trusted. If it gets corroded your solenoid will usually stop working first, because that needs a solid ground to work.
Currently Inspected and Insured as of Jan 2013:
-1985 Eagle Station Wagon 258 T5 Stickshift
-1980 Eagle Station Wagon 258 Auto Fuel-injected with GM TBI

Minor Repairs Underway:
-1982 Eagle SX4 258 T5
-1981 Kammback 2.5L Iron Duke T5

Restoration Efforts Near Completion:
-1982 SX4- 401 NV3550
-1983 SX4- 4.5 MPI NSG370 (6 Speed)

Restoration Efforts Underway:
-1985 SW- 4.0 MPI AX15
-1982 SX4- 4.0 AW4
-1981 SX4- SD33T NV4500 (Turbodiesel 5 speed)

Future Rescue Efforts- '85 Maroon SW, '87 Limited SW, '84 Limited SW, '87 4 door Sedan, '81 2 door Sedan, '88 White SW, '77 4 door Hornet, '74 2 door Hornet, '79 Spirit AMX, '81 Kammback.

RIP- Red '81 SX4, '84 4dr Sedan, '84 SW, '81 SW, '80 Spirit, '83 SW, '83 4dr Sedan

Offline captspillane

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Re: Best New ICM
« Reply #8 on: September 08, 2012, 07:19:30 PM »
A fire occured and it welded itself to the body. Fact.

If you disconnect your grounding strap your car body goes hot. The body was no longer grounded but it was still connected to the hot side of the battery through a multitude of resistors. That makes it a false 12V. All open circuits behave that way. Once you close the circuit then you see a different potential value at any node. There is a transient state where the system changes to reach a new state of equilibrium, where the car body would read a potential value 12V less than the positive post of the battery.

Your argument is as wrong as stating that touching the positive side of a AA battery against the negative side of a different AA battery would start a fire. Everyone who has put two batteries against each other inside a flashlight knows thats not true. Voltage is a relative value to something else, not an absolute value (like temperature).
« Last Edit: September 08, 2012, 09:50:55 PM by captspillane »
Currently Inspected and Insured as of Jan 2013:
-1985 Eagle Station Wagon 258 T5 Stickshift
-1980 Eagle Station Wagon 258 Auto Fuel-injected with GM TBI

Minor Repairs Underway:
-1982 Eagle SX4 258 T5
-1981 Kammback 2.5L Iron Duke T5

Restoration Efforts Near Completion:
-1982 SX4- 401 NV3550
-1983 SX4- 4.5 MPI NSG370 (6 Speed)

Restoration Efforts Underway:
-1985 SW- 4.0 MPI AX15
-1982 SX4- 4.0 AW4
-1981 SX4- SD33T NV4500 (Turbodiesel 5 speed)

Future Rescue Efforts- '85 Maroon SW, '87 Limited SW, '84 Limited SW, '87 4 door Sedan, '81 2 door Sedan, '88 White SW, '77 4 door Hornet, '74 2 door Hornet, '79 Spirit AMX, '81 Kammback.

RIP- Red '81 SX4, '84 4dr Sedan, '84 SW, '81 SW, '80 Spirit, '83 SW, '83 4dr Sedan

Offline captspillane

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Re: Best New ICM
« Reply #9 on: September 08, 2012, 08:01:42 PM »
Here are some real life examples. The negative battery post has a clamp around it that goes to the engine block. Imagine if you reached into the hood of your Eagle and unbolted the end of the cable at the engine block, then touched that against the hot post of the battery. You would be shorting the battery. Sparks would fly as soon as you touched the end of the wire against the post and sometimes the arc will weld the metal and get stuck there, in turn melting the insulation right off the wire and possibly making the battery explode. Just because its a cable with black insulation on it to signify that it typically provides ground to other components doesn't mean it can't create sparks and a short circuit. Likewise the car body is usually the ground to other components closer to the high voltage in the circuit. That doesn't mean it can't become a source of high voltage as soon as the ground is disconnected.

Now imagine if you car was stored with the clamp around the negative post loosened and set aside, but the headlight switch was still left on. As soon as you touched the negative clamp against the negative terminal the headlights would flicker on and a spark would fly from the clamp. Even though the clamp provides ground to other components like the headlights, it's still an extension of the positive post and positive in relation the negative post right up until the moment it makes contact with the negative post and closes the open circuit. The sparks won't be too bad because of the voltage drop across the headlight resistance, but they will still be there. If during storage you also accidently cut the wires going to the headlights and there was a dead short present in the circuit before you connected the battery, then the sparks would be pretty severe. Anyone who has connected jumper cables improperly knows how bad those sparks can be.

At any point in an open circuit, regardless if its a grounding cable or not, there can be sparks present. An open circuit behaves differently than a closed circuit. The car body will have a potential value 12 volts higher than the grounding cable if it breaks and the grounding cable will still be ground. If it swings around after breaking and makes contact with the side of the subframe sparks will fly and it could weld itself to the car body and a fire can start. It happened to me. A piece of ground strap is still welded to my subframe right now. I had a great deal of damage done to my starter and most of my wiring harness because of the fire.

I was driving the car when it happened. I noticed immediately a severe loss of power and the car started to barely run. The headlights started to flicker and flash. All the dashlights flashed together with the headlights. The engine surged alive and back to nearly dead to the exact same pattern. I had to use the clutch to restart the engine and then start overrevving it to keep it barely running after it stalled out. I suddenly realized that the song playing on the radio was the source of the surges. My entire car turned into a disco mobile, like those flashing lights at the bottom of '70s juke boxes. I figured out much later that when the ground strap burned up and destroyed my entire starting system and most of my wiring harness the only intact ground wire in the entire car was the 10 gauge wire I had run directly from the battery to the new radio. That became the only source of ground to the entire car. The headlights, ignition, and dash lights all got their ground through the radio. As the song played the entire car went to the beat of the song. It was groovy. I thought it was hilarious until I found out about the destruction in my engine bay. I was driving home from work and the car made it home. I had to drive my Eagle Station Wagon for a week after that while I repaired the starter in the SX4.

« Last Edit: September 08, 2012, 10:00:31 PM by captspillane »
Currently Inspected and Insured as of Jan 2013:
-1985 Eagle Station Wagon 258 T5 Stickshift
-1980 Eagle Station Wagon 258 Auto Fuel-injected with GM TBI

Minor Repairs Underway:
-1982 Eagle SX4 258 T5
-1981 Kammback 2.5L Iron Duke T5

Restoration Efforts Near Completion:
-1982 SX4- 401 NV3550
-1983 SX4- 4.5 MPI NSG370 (6 Speed)

Restoration Efforts Underway:
-1985 SW- 4.0 MPI AX15
-1982 SX4- 4.0 AW4
-1981 SX4- SD33T NV4500 (Turbodiesel 5 speed)

Future Rescue Efforts- '85 Maroon SW, '87 Limited SW, '84 Limited SW, '87 4 door Sedan, '81 2 door Sedan, '88 White SW, '77 4 door Hornet, '74 2 door Hornet, '79 Spirit AMX, '81 Kammback.

RIP- Red '81 SX4, '84 4dr Sedan, '84 SW, '81 SW, '80 Spirit, '83 SW, '83 4dr Sedan

Offline carnuck

  • Having a 727 means never re-doing the trans again
  • AMC Eagles Den Addicted
  • ********
  • Posts: 3451
  • Thumbs Up 89
  • Near Seattle
    • Virtual Jeep
Re: Best New ICM
« Reply #10 on: September 10, 2012, 10:30:43 AM »
Exactly so. If the ground strap goes bad, the little wire between the module on the fender and the dist becomes the only source of ground and it burns out pretty quickly.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline masternull

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Re: Best New ICM
« Reply #11 on: November 20, 2012, 01:38:26 PM »
anyone have any experiences using:

BWD Select - Ignition Control Module
Part # CBE7



 

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