Won't start one day and fires up first crank next day

-
When I got my car back from a shop, the car wouldn't run. Most of the wiring you see in my pic is from the shop. I removed the ballast and found the ECU only bolted on the bottom flange with a sheet metal bolt. They drilled 6 fn holes in my firewall for the ECU and only one lined up and was used. I know it is not grounded properly, I have work to do.

Any pics of what good looking ECU wiring looks like?
I can describe it. I always remove those colored plastic covers from the terminals. Only reason they are there is to look stupid. ....no offense. Moreover, look at how the terminals are not sealed where the wires are inserted and crimped. Once I remove the plastic, I slide a piece of appropriately sized shrink sleeve on the wire(s), make my crimp, slide the shrink sleeve over the connection and heat it to shrink. Makes for a nice sealed connection that will not fail from corrosion, plus, it looks MUCH more professional.

Not sayin all this to knock your stuff so please don't take it that way. Those cheap store bought terminals are only meant for temporary repairs anyway. Doing away with the plastic covers and using the shrink sleeve makes them much more permanent.
 
When I got my car back from a shop, the car wouldn't run. Most of the wiring you see in my pic is from the shop. I removed the ballast and found the ECU only bolted on the bottom flange with a sheet metal bolt. They drilled 6 fn holes in my firewall for the ECU and only one lined up and was used. I know it is not grounded properly, I have work to do.

Any pics of what good looking ECU wiring looks like?
I would also use a separate ground wire for the ECU. You don't have to, but it's simply a personal preference of mine.
 
Simplify this a bit, I have not read threw all the great help here, I have had the same problem, coil would heat up and not start on a truck I had, changed it out an no more problems of not starting
 
Simplify this a bit, I have not read threw all the great help here, I have had the same problem, coil would heat up and not start on a truck I had, changed it out an no more problems of not starting
yeah seen that before when hot there is a short in the coil when cool it goes away. presume caused by pressure due to oil movement in the caseing when hot
 
I haven't read the whole thread but I had the internal pickup module inside the distributor go bad some years back. It would start 20 times, then crank with no spark like the coil was unhooked. Then sit an hour, and be 100% fine. Never stalled once running. Just no spark no starts.

Was around $15 at autozone at the time. I see they went up. New distributor may be cheaper
1975 DODGE DART 5.2L 318cid V8 Distributor | RockAuto


Example of the pickup
1975 DODGE DART 5.2L 318cid V8 Distributor Pickup Coil | RockAuto

I assume it's a SB...
 
We have a non standard ignition system! This is not in the factory location or even Factory wiring!

What else may be hiding behind it? I will leave this to DEL!

Why Do Folks make this harder than that is needed?
 
I can describe it. I always remove those colored plastic covers from the terminals. Only reason they are there is to look stupid. ....no offense. Moreover, look at how the terminals are not sealed where the wires are inserted and crimped. Once I remove the plastic, I slide a piece of appropriately sized shrink sleeve on the wire(s), make my crimp, slide the shrink sleeve over the connection and heat it to shrink. Makes for a nice sealed connection that will not fail from corrosion, plus, it looks MUCH more professional.

Not sayin all this to knock your stuff so please don't take it that way. Those cheap store bought terminals are only meant for temporary repairs anyway. Doing away with the plastic covers and using the shrink sleeve makes them much more permanent.

RRR, no offense taken, it looked worse before I cleaned it up. The details you provide is exactly what this old man is looking for.

I want to say thanks to all that gave me some input, I want to learn/understand not just fix the problem. I found and fixed two issues that I hope will keep the "no spark when cranking" from coming back. First found my ecu had little to no ground at the firewall, bolted it back on with bare surfaces and a star washer. Secondly I found the top half of my dual ballast measured 5.6 ohms and I read it should be 0.8 to 1.5 ohms. Bought a new single resistor ballast (0.8 ohm)that is for my car and it fires everytime since install.

Took it for my first pleasure ride since BB 413 install and criused the river near sac.

thx
 
We have a non standard ignition system! This is not in the factory location or even Factory wiring!

What else may be hiding behind it? I will leave this to DEL!

Why Do Folks make this harder than that is needed?
No standard for sure but just the dist/ecu/eng/trans are not stock. Would love simpler, PM me if you want to go into detail.
 
You have something AFU here. "technically" that has the correct side of the ballast going to the coil but you are confusing you AND us because it doesn't follow factory. Review the diagram and reverse the ballast PHYSICALLY so you can wire it per diagram.

image-jpg-jpg.jpg

You have the correct side of the resistor going to the box, but you have a whole bunch of crap on top left that is evidently hooked to the coil. The two on the right should go to the "run" wire from the key.

So fix it so it matches the diagram and then we can get more serious. Physically re-mount the ballast "other end to" and hook the two jumpered terminals to the end opposite the "U" cutout. Then connect the green box wire to the new top left, and then troubleshoot "what all" is hooked to all those reds. They hook to bottom left. THE ONLY things that should be there is a radio suppression cap, the coil +, the wire from IGN2 from the key.
image000000-13-jpg.jpg
 
Last edited:
You have something AFU here. "technically" that has the correct side of the ballast going to the coil but you are confusing you AND us because it doesn't follow factory. Review the diagram and reverse the ballast PHYSICALLY so you can wire it per diagram.

View attachment 1715944466
You have the correct side of the resistor going to the box, but you have a whole bunch of crap on top left that is evidently hooked to the coil. The two on the right should go to the "run" wire from the key.

So fix it so it matches the diagram and then we can get more serious. Physically re-mount the ballast "other end to" and hook the two jumpered terminals to the end opposite the "U" cutout. Then connect the green box wire to the new top left, and then troubleshoot "what all" is hooked to all those reds. They hook to bottom left. THE ONLY things that should be there is a radio suppression cap, the coil +, the wire from IGN2 from the key.
View attachment 1715944467
View attachment 1715945460
image000000 (12).jpg

Here is my wiring for 69 Dart, all the colors match my wiring except at ballast since originally it had a single ballast resister. I did reverse the ballast as you and many others suggested but same results. Are you and others saying the resistance changes when the wires are reversed? Not on any resister I know of or it wouldn't be a resistor, correct?

Let's talk about the last line of you statement above. The brn wire in my pic is ign2 from key switch, the org and only org goes to the coil. The red is carb choke and can be hooked elsewhere but is sharing the output from the resistor currently. Help me understand how I am wrong.

The my mopar pic doesn't show ign2 hooked direct to resistor and then to coil without going thru resistor.

Please anyone jump back in. thx
 
That ECU is definately a newer "replaces" one. Definately have seen worse wiring. I would find the plastic plugs for the ballast they are around.
I'd like to find some of them also as far as the duel ballast register connenctors/protectors(plugs?).
 
View attachment 1715945460
View attachment 1715945463
Here is my wiring for 69 Dart, all the colors match my wiring except at ballast since originally it had a single ballast resister. I did reverse the ballast as you and many others suggested but same results. Are you and others saying the resistance changes when the wires are reversed? Not on any resister I know of or it wouldn't be a resistor, correct?

Let's talk about the last line of you statement above. The brn wire in my pic is ign2 from key switch, the org and only org goes to the coil. The red is carb choke and can be hooked elsewhere but is sharing the output from the resistor currently. Help me understand how I am wrong.

The my mopar pic doesn't show ign2 hooked direct to resistor and then to coil without going thru resistor.

Please anyone jump back in. thx

You misread what I intended. You technically have part of the resistor wired correctly, but it does not follow the diagram. That is, you have the resistors hooked correctly, but the jumper is on the wrong end. This makes it more diffecult to troubleshoot "for us" because we see "the wrong end."

The thing you DO HAVE wrong is the CHOKE does not belong on the coil connection. This puts more load on the resistor and robs drops coil voltage lower. Connect the choke to the end with the jumpers, which should be "key run" IGN1

To confuse the resistance thing further, or not---the 4 pin resistor is TWO resistors. One side is basically the same as a breaker points system and is wired the same. The second one is also supplied from the "run" line and feeds only the box. There are darn few true 5 pin boxes, and even though a box has 5 physical pins, the odds are that it is in reality a 4 pin box electrically. This means the half of the ballast feeding the ECU is not actually doing anything.
 
brn is ign2 from ign switch, red is to elect choke, org to coil. Ign2 supplies coil during cranking I believe.
So to simplify this. Yes you are correct.
The only, but important, downside to this scheme is powering an electric choke through the ballast resistor.

Factory '69 scheme is like this.
upload_2019-9-27_12-47-7-png.png

Probably the best place to draw power for the choke will be at the Regulator's terminal. That way the additional current for the choke heater will flow through wire J2 which is 16 gage, and not J2A which is I think is only 18 gage.

Factory location for the ballast was under the lip, protected from rain and snow.
See here for illustration.
 
So to simplify this. Yes you are correct.
The only, but important, downside to this scheme is powering an electric choke through the ballast resistor.

Factory '69 scheme is like this.
View attachment 1715945597
Probably the best place to draw power for the choke will be at the Regulator's terminal. That way the additional current for the choke heater will flow through wire J2 which is 16 gage, and not J2A which is I think is only 18 gage.

Factory location for the ballast was under the lip, protected from rain and snow.
See here for illustration.

I do understand that the choke shouldn't be powered from that point on the ballast and will be disconnected tomorrow(not needed for now). The shop that worked on my car installed the ballast and made a lot of bad choices as well as shitty work.
 
...................And while we are "on" all this, it is VERY common for voltage drop through the ignition switch circuit. What this does, other than robbing voltage when the charging output is low, is to actually cause OVER voltage output from the alternator, because the VR "thinks" the battery is low. It is a wise idea to check this, and if it exists, fix it or workaround.

One way is to install a relay. Trigger the relay from the "run" wire, break off th eloads, and power the loads from the relay contacts

TO CHECK

Turn key to "run" engine stopped. Measure between the ballast "run" terminal and battery PLUS post. You are hoping for a very low voltage, lower the better, Anything over about .3V (3/10 of one volt) you should go shopping for the cause.

Same on VR ground. Check it with engine running simulated "low to medium cruise" RPM. Stab one probe of your meter into the top of the battery NEG post, and the other into the mounting flange of the VR. Lower the better, zero is perfect VR MUST be grounded to battery NEG
 
You misread what I intended. You technically have part of the resistor wired correctly, but it does not follow the diagram. That is, you have the resistors hooked correctly, but the jumper is on the wrong end. This makes it more diffecult to troubleshoot "for us" because we see "the wrong end."

The thing you DO HAVE wrong is the CHOKE does not belong on the coil connection. This puts more load on the resistor and robs drops coil voltage lower. Connect the choke to the end with the jumpers, which should be "key run" IGN1

I get it and the choke will be disconnected tommorrow. thx

To confuse the resistance thing further, or not---the 4 pin resistor is TWO resistors. One side is basically the same as a breaker points system and is wired the same. The second one is also supplied from the "run" line and feeds only the box. There are darn few true 5 pin boxes, and even though a box has 5 physical pins, the odds are that it is in reality a 4 pin box electrically. This means the half of the ballast feeding the ECU is not actually doing anything.

Let me see if I understand your 5 pin or 4 pin box comment. Two wires from the box go to opposite sides of the bottom resistor and both wires are getting almost the same voltage. If one wire is not needed, I can disconnect them one at a time and the car should still run? I I can remove one of the wires I won't need the dual ballast.
 
...................And while we are "on" all this, it is VERY common for voltage drop through the ignition switch circuit. What this does, other than robbing voltage when the charging output is low, is to actually cause OVER voltage output from the alternator, because the VR "thinks" the battery is low. It is a wise idea to check this, and if it exists, fix it or workaround.

One way is to install a relay. Trigger the relay from the "run" wire, break off th eloads, and power the loads from the relay contacts

TO CHECK

Turn key to "run" engine stopped. Measure between the ballast "run" terminal and battery PLUS post. You are hoping for a very low voltage, lower the better, Anything over about .3V (3/10 of one volt) you should go shopping for the cause.

Same on VR ground. Check it with engine running simulated "low to medium cruise" RPM. Stab one probe of your meter into the top of the battery NEG post, and the other into the mounting flange of the VR. Lower the better, zero is perfect VR MUST be grounded to battery NEG

I'll check tomorrow morning
 
Let me see if I understand your 5 pin or 4 pin box comment. Two wires from the box go to opposite sides of the bottom resistor and both wires are getting almost the same voltage. If one wire is not needed, I can disconnect them one at a time and the car should still run? I I can remove one of the wires I won't need the dual ballast.

The 5th wire on original factory ECUs was a part of the internal power control. Later the factory and aftermarket was able to incorporate solid state control into the units.
The ECU draws only a little power as all it does is amplify the magnetic pulse (wires to the distributor). Then use that to make and break the primary coil circuit, same as points. The transistor on the top does get hot but we're not talking about more than an amp or so as far as draw.


upload_2022-6-23_8-28-35.png


I suggest not using a relay unless you get in a bind, especially if the resistance in the R6(alterntor out) or J1 (switch feed) connections.

If you want to make nice factory like connections, get some open barrel crimpers and selection of Packard type 56 and 58 type terminals.
 
Last edited:
We have a non standard ignition system! This is not in the factory location or even Factory wiring!

What else may be hiding behind it? I will leave this to DEL!

Why Do Folks make this harder than that is needed?
Nobody makes anything harder. It's already harder than is needed BECAUSE THIS IS AN ONLINE DIAGNOSIS. I don't understand why there's a faction that always BLAMES people for making things difficult, when it already is. We're not in person! If you think it's so mofokin easy, then here's an idea. SOLVE IT FOR HIM RIGHT NOW! Otherwise, take your blaming BULLSHIT somewhere else! All everyone is trying to do here is help someone whose car we cannot even TOUCH. It's hard enough already, genius.
 
67Dart273, thanks for the info on the ecu. Turns out it will work with either input so I don't need the dual ballast. Here it is currently.

image000000 (15).jpg


I believe, as I stated days ago, that I have fixed my starting issue and improved things greatly with every ones help and knowledge.
thx

image000000 (15).jpg
 
-
Back
Top