Mopar ECU Orange Box Strange Issues

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berlins

BerlinS
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Here's a good one hope someone can help me with. Got a 67 Dart with the
Orange Mopar electonic ignition on it. Always have had trouble with no spark sometimes starting it - both with the 273 it had and now the 360.
Put in a rebuilt distributor from Autozone - ran fine for a while. Pulled the coil wire off the distrib and found out after you crank it a short while, the spark quits.
From this web site I see that a lot of people have had issues with the Orange ECU so went to AutoZone and got it's replacement which is CR109. Did the crank test and the spark doesn't go away - I thought, problem solved!!! Starts real nice. Took it down the road and it won't
rev up, think it's dieing around 3-4k. So, went to AutoZone and got
another ECU, hooked it up, same thing. Played around with the distrib
relutor gap, still woundn't rev up. Hooked up the Orange box again(has 4 pins), revs fine. Anyone got any ideas??? CR109 is the correct Orange Box replacement, isn't it? Seems to be all they sell anyway.
 
Had a similar problem,thought it was the ecu. But figured out the ecu wasnt making good ground. Clean the area where it contacts the firewall and added a ground strap and havent had problem since.
 
i dont know if this is related but its basically what khaley71 is saying...


a while back, i had a similar problem develop. i was getting intermittent spark. i would turn the key and it would not fire until the key was on its way back to the start position. i would crank it a few times , then it would start. it gradually got worse until it would not start at all. i pulled the ECU box off, stuck a new one on there, it fired and ran immediately. then a couple days later, it happened again. im thinking WTH? i pulled the ECU off, took a flap disc to the box mounting tabs and the fender apron where the ECU mounts and sanded all the surfaces to bare metal. i re-mounted the box, it has been working flawlessly for 2 months now.
 
I had a 74 Valiant that did the same thing. Idle all day. But it wouldn't rev
up. Cleaned up the ground and it ran perfect. The Orange box is heating up
because of the bad ground. Run an extra ground from the box to ground.
Just for safety sake.
 
Will redo grounds but I now have 2 wires going from ECU to negative on battery.
 
have you checked your vacuum advance in the distributor? You bought a rebuilt one but they're kind of one size fits all and unless you've got a dead stock engine you might need different weights etc....and definitely check the ground strap if that box got hot, the black "goop" on the back side probably got a bit melted and you're going to want to replace it:)
 
only ground I see is block to battery, where's the coil to ground go? thought one post ent over to ECU and other went to distrib. I guess all these other grounds are
just 18 gauge grounds? Only one I've ever seen is the block to the battery.
 
berlins said:
only ground I see is block to battery, where's the coil to ground go? thought one post ent over to ECU and other went to distrib. I guess all these other grounds are
just 18 gauge grounds? Only one I've ever seen is the block to the battery.
Click to expand...

you need a block to body ground strap which needs to be clean and good. sorry for any confusion, im talking about your negative side on the coil itself. . this is for a 5 pin ECU
 

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A voltmeter is your trouble shooting friend. Check the voltage on the brown wire when cranking, the blue wire when in "RUN". If either is less than a few tenths of the battery voltage, there is likely a connection issue at the bulkhead connector. If those check good, the measure voltage at the coil + terminal. It should likely be above 7V.
 
thanks for the wiring schmatic, will recheck tomorrow. Mine is the 4 pin unit.
I added a gound wire from the coil outside shell to the battery negative - no
go. Don't know how to check steering colum groud. What gets me is that it
revs up OK with the Orange ECU box but won't with the 2 new CR109s that
I have tried from Autozone. Ohmed out the 4 pins on both ECUs to ground and
they give about the same resistance levels. Tried orignal distributor also, revs
with orange, not with CR109 ECU, now checking wiring with above schmatic.
 
OK, I'm stumped, wiring checks out. Runs fine(starts hard) with Orange ECU,
2 different CR109s from AutoZone, starts great, revs fine till 2500 then craps
out. Even disconnected from alternator after start and it craps out at 2500,
Added extra ground wire to ECU, reads almost 0 between - battery and ECU.
Is the CR109 the wrong ECU for this???? New ideas anyone???
 
berlins said:
OK, I'm stumped, wiring checks out. Runs fine(starts hard) with Orange ECU,
2 different CR109s from AutoZone, starts great, revs fine till 2500 then craps
out. Even disconnected from alternator after start and it craps out at 2500,
Added extra ground wire to ECU, reads almost 0 between - battery and ECU.
Is the CR109 the wrong ECU for this???? New ideas anyone???
Click to expand...

you may have a 5 pin ecu with your 4 pin system. im not sure if it matters, 67Dart273 might chime in on this in a while.
 

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Hey, thanks everyone for the info, the schmatic 73abodee fixed it for me. I had the
wire going to the ballast resister on the wrong side. Put it on the other side and it
starts and revs fine now. Guess the AutoZone ECUs need that little extra voltage to run correctly, the Orange box worked fine.
 
berlins said:
Hey, thanks everyone for the info, the schmatic 73abodee fixed it for me. I had the
wire going to the ballast resister on the wrong side. Put it on the other side and it
starts and revs fine now. Guess the AutoZone ECUs need that little extra voltage to run correctly, the Orange box worked fine.
Click to expand...

and you know, i should have thought about that. one of the pins on my ballast connectors was broken off and i had the plug upside down causing major problems until i caught it. glad you got it fixed
 
Well I see I got here late. I'm surprised any of 'em ran good with the wrong side of the resistor.
 
berlins said:
wire going to the ballast resister on the wrong side.
Click to expand...
OK, now please wrap it up for us late-comers. Do you mean that you had the output wires from the dual ballast swapped? I thought the connectors were keyed to prevent that, but maybe the plastic key broke off.

If so, that would put 5 ohm in series with the coil (should go to original 5-pin ECU) and 0.5 ohm in series with the ECU. The later wouldn't matter since most replacement ECU's don't use that pin anyway (some have a 5th dummy pin). You would have been starving your coil for power, running ~3 V average supply, which is why it mis-fired at higher throttle. Glad you fixed it.

Before spending that much time with it, I might have installed an HEI module and coil for a simpler, more powerful ignition, but it would lose the factory look.
 
I had the negative going to the coil on OK, I have a 2 pole ballast, had the power wire on the same side as the wire going to the positive side of the coil instead of the
other side of the ballast that gets fed from the battery/alternator, it needed more
voltage. Still can't believe it ran OK with the Orange ECU since I've had it wired
wrong. Also, the CR109 is a 4 pin ECU, not 5.
 
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