American Auto Wire
Username Post: 12V for ECU        (Topic#350067)
Shoebox 
"4th Year" Silver Supporting Member
Posts: 348
Shoebox
Loc: Wisconsin
Reg: 09-28-03
03-12-18 05:38 PM - Post#2727365    

I have a 55 Chev which I wired with the AAW Classic Update harness which has been great to work with. I am adding fuel injection, the primary power leads go directly to the battery however there is a lead from the ECU that must go to "a switched 12V power source that is on for ON and CRANKING, it is critical that the 12V is constant while cranking". What is the BEST place to draw from for this?? Thanks much!

Shoebox
<a href="http://www.picturetrail.com/cool55" target="_blank">www.picturetrail.com/cool55</a>

55 2dr Sedan- 454 4spd, R&P steering, 4 whl disks
32 Roadster- Nailhead 401, Tremec 5 spd

"I came, I saw, ....and I bought the T shirt"


 
acardon 
Ultra Senior Member
Posts: 11059
acardon
Loc: DFW TEXAS
Reg: 03-25-05
03-13-18 06:23 AM - Post#2727439    
    In response to Shoebox

If your using the original type ignition switch, you have to jumper "ign1" and "ign2" together to get 12v in both crank and run. If your using the update switch, "ign" will provide voltage in both positions.



Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
aawtech 
American Autowire "Site Sponsor"
Posts: 5071

Loc: Bellmawr, NJ
Reg: 09-11-06
03-14-18 05:55 PM - Post#2727631    
    In response to Shoebox

  • Shoebox Said:
I have a 55 Chev which I wired with the AAW Classic Update harness which has been great to work with. I am adding fuel injection, the primary power leads go directly to the battery however there is a lead from the ECU that must go to "a switched 12V power source that is on for ON and CRANKING, it is critical that the 12V is constant while cranking". What is the BEST place to draw from for this?? Thanks much!



In a word, yes. It must be a wire that is hot in crank and run. Use the pink wire we tell you to run to the distributor and use our switch we provide in the kit. It will give you 12v in both crank and run.

Donny




 
Shoebox 
"4th Year" Silver Supporting Member
Posts: 348
Shoebox
Loc: Wisconsin
Reg: 09-28-03
03-16-18 08:11 AM - Post#2727814    
    In response to aawtech

Guys, thank you for the responses! I will be studying the schematics of the AAW, the MSD box, and the Edelbrock Proflow. The Edelbrock info says to NOT connect to the coil, however in the grand scheme of things, perhaps the suggested Pink Wire no longer gets attached to the coil.

Oh, I am using the AAW ign. switch.

Shoebox
<a href="http://www.picturetrail.com/cool55" target="_blank">www.picturetrail.com/cool55</a>

55 2dr Sedan- 454 4spd, R&P steering, 4 whl disks
32 Roadster- Nailhead 401, Tremec 5 spd

"I came, I saw, ....and I bought the T shirt"


Edited by Shoebox on 03-16-18 08:13 AM. Reason for edit: No reason given.

 
acardon 
Ultra Senior Member
Posts: 11059
acardon
Loc: DFW TEXAS
Reg: 03-25-05
03-16-18 10:17 AM - Post#2727824    
    In response to Shoebox

  • Shoebox Said:
The Edelbrock info says to NOT connect to the coil,
Oh, I am using the AAW ign. switch.



Many times the coil will have a resistance wire or ballest reesistor. In the case of stock tri-5's, the 20 gauge wire from the ignition switch is too small to carry the extra load of the computer. I think Donny will confirm the pink wire can be used for the MSD box and the ECU.


Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
Shoebox 
"4th Year" Silver Supporting Member
Posts: 348
Shoebox
Loc: Wisconsin
Reg: 09-28-03
03-17-18 01:59 PM - Post#2727968    
    In response to acardon

Don,
Thanks for the response, we'll see if Donny comes back on this.

Shoebox
<a href="http://www.picturetrail.com/cool55" target="_blank">www.picturetrail.com/cool55</a>

55 2dr Sedan- 454 4spd, R&P steering, 4 whl disks
32 Roadster- Nailhead 401, Tremec 5 spd

"I came, I saw, ....and I bought the T shirt"


 
aawtech 
American Autowire "Site Sponsor"
Posts: 5071

Loc: Bellmawr, NJ
Reg: 09-11-06
03-17-18 08:19 PM - Post#2728000    
    In response to acardon

  • acardon Said:
  • Shoebox Said:
The Edelbrock info says to NOT connect to the coil,
Oh, I am using the AAW ign. switch.



Many times the coil will have a resistance wire or ballest reesistor. In the case of stock tri-5's, the 20 gauge wire from the ignition switch is too small to carry the extra load of the computer. I think Donny will confirm the pink wire can be used for the MSD box and the ECU.




Yes, the 12 volt pink 12gauge wire marked coil that was to go to the distributor should be used as the MSD or ECU trigger. It is a true ignition "ON", unfused feed.

Donny




 
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