Shorted ignition

[Challenger RTA]

ECU started in 72 mostly a few late 340's had them in 71.

Thanks. my 71 has dual points.

 

[halifaxhop]

That was for The HP cars never leave you stranded!

 

[i_taz]

ECU started in 72 mostly a few late 340's had them in 71.

Just to be clear.I think you understand 70 had no ECU it was incorporated. some 71 340s had an ECU.mine came factory dual point. Look at the 72 and up diagram for dual ballast and ECU wiring. This might make the ecu connections simplified. An other good link. https://www.e-bodies.org/Resources/Service_Manuals/1974_Barracuda_Challenger_Wiring_Diagram.pdf Not really go to the link.

The wiring harness isn't from '70.....

Your right, The previous owner thought ahead when planning to use the electronic ignition and used the appropriate harness. The first thing I noticed missing from earlier schematics was the dual field coming out of the alternator. 1 to the choke and 1 to the ignition circuit.

I was speed reading thru this '74 video and they touched on that very circuit at 5:32...

 

[i_taz]

No real way of checking them unless you have a tester. I have a bunch of ecu's on Fabo listed if needed, not the "new fake ones" All tested Hot and cold.

Your right about the tester, I remember watching this once, actually. 07:55

 

[halifaxhop]

So far for bench checkin there is that Mopar one I have seen and a zetrron one I use and on the car I have only seen the one I have for sale and the Mopar tester..

 

[i_taz]

The good news is I now have an xtra ECU, the bad news is I now have an xtra ECU. I have continuity all over the place so I can't find any opens in the engine compartment. From the ECU to the ballast,
ECU to coil, ECU to distributor, Coil to ballast output, across the voltage reg plug

I'm trying to follow this test procedure which works from the ECU out then back to the ballast. I don't have voltage anywhere, coil, ballast, ecu, voltage reg. car cranks and it's hard to tell if it wants to fire in the 'start' position but it definitely dies in the 'run' pos...

Dave's Place - Chrysler Electronic Ignition System Test

dave78chieftain.com

1) Is the ballast input the first point to read voltage from the ignition switch in the run pos ?
2) Maybe unrelated but I'm getting over 9 ohms from the voltage reg. It shud be 1.5 I read
Can a car start w/o it...?

 

[Challenger RTA]

Sometimes a different approach is needed. Ing off unplug resistor,coil positive and ECU. protect loose ends from grounding. Turn ign on see if you have power at resistor wire to ground. If no power go to bulkhead connector,no power follow back to ing switch and connectors. same for start circuit with long wire for test lead or some one turning ing sw. may have a bad connection or bad wire. don't forget to check for good grounds. If you have power at resistor wire move forward to coil power and ecu power. car will start and run with out reg or alt.

 

[i_taz]

I'm right behind you... I was going to start poking around the ignition switch when I saw this fuse carrier spliced into a bl/wh wire.

I noticed it the other day and the fuse looked good but since I had the meter in my hand I checked again and it was open ! Changed it and it fired right up....! BUT as soon as I plugged in the
divorced choke it blew again.

I used the same lead for the electric choke on my 1411, no problem. Is there something about the
heating elements on these divorced chokes. I read where they get hooked up to the oil sending unit
but what's the difference...? The Edelbrock had a ground but I didn't think carter used one not that
there's anywhere for one to go...?

As for the voltage regulator, I'm getting 13.6v at the battery so that doesn't seem to be a problem...

 

[moparleo]

Stay simple. Did you go back to post #4, page 4 of the trouble shooter. The system is not complicated. You can do a bypass to start. Check all again.
13.6V on a battery that has had the surface charge removed is a little high. What else is going on ?

 

[i_taz]

Stay simple. Did you go back to post #4, page 4 of the trouble shooter. The system is not complicated. You can do a bypass to start. Check all again.
13.6V on a battery that has had the surface charge removed is a little high. What else is going on ?

You mean the 70's version of limp home mode... 'Meatball surgery time' ...?
That was my last resort to at least clean the plugs off. Everything is back to normal...
I'm starting to get a handle on it now but I did distinctly hear the ECU take a hit or that's
the sound it makes shutting down... ?

The volt reg is the black 3438150. Car sat for a couple days and I'm getting 13.3v now.
I'm using a standard 60 amp alt...