News:
Putting FUN and FRIENDLINESS, FIRST into owning and learning about AMC small bodied cars, primarily Eagles, Spirits and Concords as well as vehicles built in AMC's Mexican subsidiary, VAM.

  The AMC Eaglepedia can now be accessed using the buttons found below  This is a comprehensive ever growing archive of information, tips, diagrams, manuals, etc. for the AMC Eagle and other small bodied AMC cars. 

Also a button is now available for our Face Book Group page.


Welcome to the AMC Eagles Nest.  A new site under "old" management -- so welcome to your new home for everything related to AMC Eagles, Spirits and Concords along with opportunities to interact with other AMC'ers.  This site will soon be evolving to look different than it has and we will be incorporating new features we hope you will find useful, entertaining and expand your AMC horizons.  And, if you were you banned at another AMC Eagle Forum and cannot log in here?  Let us know and we will fix it for you. 

You can now promote your topics at your favorite social media site by clicking on the appropriate icon (top upper right of the page) while viewing the topic you wish to promote.


  • August 04, 2021, 03:44:32 PM

Login with username, password and session length

Author Topic: Complete Electronics bypass?  (Read 292 times)

0 Members and 1 Guest are viewing this topic.

Offline Mtmopar1992

  • Hatchling
  • *
  • Posts: 6
  • Thumbs Up 1
Complete Electronics bypass?
« on: June 23, 2021, 06:59:54 AM »
Hey Everyone, I don’t post here much, more of a lurker.

However, I purchased an ‘86 manual Eagle, and all the wiring was ate up by rats in a field, and the steering column was snapped in 3 places. But it started and runs, so now it’s in the driveway.

New steering column installed (Aftermarket Ididididit Steering Column w/ correct plugs for blinkers)

The question is though, can I remove all the wiring and just do basic wiring with possibly a different(more basic) carb and completely ditch the ecm and icm?

Fun note: I live in Montana, Smog testing/passing means nothing

Thanks everyone!

Offline Illeagle1984

  • Manic Mechanic
  • Eagle
  • **
  • Posts: 35
  • Thumbs Up 7
Re: Complete Electronics bypass?
« Reply #1 on: June 23, 2021, 07:26:21 PM »
On my '84, I changed the carb as well as removing the main computer under the dash (Mixture Control Unit, or MCU) and as much wiring as possible.  I didn't remove the ignition control module (ICM, near battery under starter solenoid); I'm sure it's possible, but the style of distributor on the 4.2 can not trigger a coil by itself, and those boxes seem to be pretty reliable.  Both my Eagles boxes appear to be original, and Ford used the same boxes in the 80's medium duty trucks like the F600.

To bypass that other computer, though, you need to change the ignition system wires around.  Instead of going through the MCU, the distributor and coil wires go straight to the ICM.  I have a before/after wiring diagram if you're interested, but I don't have it on my current computer.  I will need to dig through my box of hard drives, it's in there somewhere.  ::)

Also, my modded Eagle is not here, but I can tell you exactly how to rewire the ignition system based off it.  I think it was only three wires that were necessary to change. I will have a look and get back to you in a day or two, unless someone else can provide that information.  There's quite a few people here both skilled and dedicated.  Good luck with your new Eagle! 
1973 Ford Mustang "Rustang"
1984 AMC Eagle Sedan "IllEagle" 181k
1984 AMC Eagle Wagon
1996 Cadillac Eldorado 176k
1998 Oldsmobile Eighty-Eight 239k
2002 Cadillac Eldorado Doral Edition

Offline amcfool1

  • Eagle Limited
  • *****
  • Posts: 588
  • Thumbs Up 30
Re: Complete Electronics bypass?
« Reply #2 on: June 23, 2021, 11:34:42 PM »
hi, which Ididit steering column did you get? Any pictures? thanks,  gz

Offline Mtmopar1992

  • Hatchling
  • *
  • Posts: 6
  • Thumbs Up 1
Re: Complete Electronics bypass?
« Reply #3 on: June 24, 2021, 12:33:09 AM »
Good luck with your new Eagle!

Thanks!! Yeah I think its definitely possible. I'm going to look into ignition bypasses when i get back into it. Unfortunately my curiosity for this project decided to peak during my busy season with work  :'(

Offline Mtmopar1992

  • Hatchling
  • *
  • Posts: 6
  • Thumbs Up 1
Re: Complete Electronics bypass?
« Reply #4 on: June 24, 2021, 12:38:10 AM »
hi, which Ididit steering column did you get? Any pictures? thanks,  gz

You know i completely forget the model number, but i got a Bare metal one with the same GM plug as the OE Eagle column has, and blinkers only (Everything else can go on a switch rather than trying to feed onto a ridiculous wiring harness). I also got a length-adjustable one so i could fiddle with the fitment, which was in Hindsight, a good idea.

Only issue is that the OE steering column bridge inside the cabin is much too large for any aftermarket column, so you'll have to either fab up a little simple brace or be me and stuff it with a circular piece of high density contact-hold foam.


Soon as i'm back in the groove after this busy spell with work, i'll definitely make a post on it!

Offline amcfool1

  • Eagle Limited
  • *****
  • Posts: 588
  • Thumbs Up 30
Re: Complete Electronics bypass?
« Reply #5 on: June 24, 2021, 09:58:15 AM »
ok, thanks, looking forward to it!    gz

Offline Illeagle1984

  • Manic Mechanic
  • Eagle
  • **
  • Posts: 35
  • Thumbs Up 7
Re: Complete Electronics bypass?
« Reply #6 on: June 27, 2021, 12:06:16 PM »
Okay, I peeled open my wiring loom to get a look at my wiring and found my wiring diagram.  Sorry it took a while, I wanted to give you a complete answer.  There's a bit more to it than I thought; I will definitely document the process when I do it to my other Eagle.  So here's what I found.

There are two plugs off the ICM: a two wire with white and red (plug 1), and a four wire with green, orange, black, and violet (plug 2).  If it's the same on yours, we're off to a good start.

On plug 1, the white goes to green and I think went through one of the CEC connectors before going to the bulkhead, so I just cut it out of that connector..  Not sure what it does, but there was no power there with my test light.  The red wire turns to yellow and has key-on power coming from the ignition switch, again through the bulkhead.  I may have used a wire originally used to power up the other computer.  It might also be that I cut out a splice there to remove other wires.  You might be able to leave these wires alone for now.

Plug 2 is where the magic happens.  The green wire goes to the dark green wire on the negative terminal on the coil.  The orange, black, and violet wires go to the same color wires on the 3-wire distributor plug.  Keep that twisted pair twisted.

Also the yellow wire on the positive terminal of the coil now goes straight to the resistor wire (red with green tracer).  The resistor wire is there to keep the ICM from burning out by pulling too many amps through the coil.  It says 'do not cut or splice,' but I kept it the full original length when I put it to the yellow wire and it seems to work fine.

Attached are a couple wiring diagrams.  The first one is the original diagram; the second is an incomplete modified version of my particular Eagle with all the CEC stuff removed and the ICM rewired (mostly).  Also note the ballast resistor between yellow and red resistor wire; I put an MSD coil on mine with less resistance than stock and so required yet more resistance to keep the amps to the ICM in check.  You wouldn't use that on a stock coil.

I hope this helps you out; if want to know more about simplifying your entire engine bay, I could put together something for you on that as well.
« Last Edit: June 27, 2021, 12:21:00 PM by Illeagle1984 »
1973 Ford Mustang "Rustang"
1984 AMC Eagle Sedan "IllEagle" 181k
1984 AMC Eagle Wagon
1996 Cadillac Eldorado 176k
1998 Oldsmobile Eighty-Eight 239k
2002 Cadillac Eldorado Doral Edition

Offline Mtmopar1992

  • Hatchling
  • *
  • Posts: 6
  • Thumbs Up 1
Re: Complete Electronics bypass?
« Reply #7 on: July 11, 2021, 03:58:18 PM »
These were a huge help thank you for going through the trouble! I’ll have results here in the next week or so hopefully.

 

SMF spam blocked by CleanTalk