• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

No power to coil wire when cranking. Help ty

Vertburt

Vertburt

Well-Known Member
Local time
12:43 PM
Joined
Aug 21, 2019
Messages
74
Reaction score
14
Location
Chelsea al
Hey guys. 1970 satellite was running with 318. Swapped to 440, the positive coil wire gets power in the run position but when I crank it,I lose power to the wire until I go back to run position. Any ideas ? What has changed threw the engine swap. Had points now electronic ignition but this seems to be a problem before I get to the coil. Please help thanks.
 
The ballast resistor is bad, you can jump across it to check.
 
What you’re describing sounds like an ignition switch problem. Run you have power and crank you don’t. Stick your VOM on the ballast resistor and see what’s happening into that. Work your way back from there. I’m not familiar with the electronic conversion, did you do a Mopar type conversion with a new distributor or something like a Pertronix conversion?
 
Ok. I put a new switch in last year getting the car running with 318, has sat in garage since. I first used original electronic distributor out of 1972 with ecu box and now I put a run ready distributor in before I found that my problem is no power to coil wire while cranking.
 
steve340 said:
You may have left a wire off.
Mopars have a cranking and a run feed.
Click to expand...
Hi. Would that be on the starter ? I have positive battery cable and small wire that goes to tarter relay that I replaced. Where would these be. Thanks
 
No I think they go either side of the ballast resisitor.
12V direct to the coil while cranking and the run one is reduced by the ballast resistor.
I think on my car they are both blue so you may have a spare one floating around on the firewall.
 
Whos electronic ignition?? Maybe a review of the wiring schematic or put up some details of the conversion?
 
If you have an orange box, silver or the blueish one they are pretty simple to wire. Got this info from Daves place. HERE

IMAG008.gif


Notes
  • A voltmeter with a 20,000 ohm/volt rating and a 1 1/2 volt battery powered ohmmeter are required.
  • Car battery voltage must be at least 12 volts.
CAUTION
Make sure the ignition switch is off when removing or replacing the control unit connector.

**** Engine trys to start but shuts off when ignition key is returned to run position ****
No voltage at plus (+) terminal of coil when ignition key is in RUN position.

Note:
The fact that the engine tries to start (fires) when the ignition key is in START position indicates that the Distributor, ECM and coil are working. It also means battery voltage is being applied to the input side of the Ballast resistor and ECM pin 1.

  1. Verify 12VDC on input side of Ballast Compensating Resistor (Connector with 2 red wires).
  2. Replace Ballast resistor.
  3. Compensating Resistor resistance value - 0.5 to 0.6 ohms
**** Engine will not fire with ignition key in either start or run position ****
CAUTION:
Make sure the ignition switch is off when removing or replacing the control unit connector. Disconnecting the plug from the ECM with the Ignition key ON can damage the ECM module.

  1. Turn Ignition Switch OFF.
  2. Remove wiring plug from the Control Unit (ECM).
  3. Ground negative voltmeter lead.
  4. Connect voltmeter positive lead to the harness connector cavity No. 1.
  5. Turn Ignition Switch to RUN.
  6. Verify voltage is within 1 volt of battery voltage with all accessories off.
    If correct voltage is present, go to step 36 (problem in wiring path to battery from ECM pin 1) otherwise continue to next step.
ecudia.jpg
 
Lefty71 said:
Whos electronic ignition?? Maybe a review of the wiring schematic or put up some details of the conversion?
Click to expand...
Hi. Seems my problem is before
BeepBeepRR said:
If you have an orange box, silver or the blueish one they are pretty simple to wire. Got this info from Daves place. HERE

View attachment 857702

Notes
  • A voltmeter with a 20,000 ohm/volt rating and a 1 1/2 volt battery powered ohmmeter are required.
  • Car battery voltage must be at least 12 volts.
CAUTION
Make sure the ignition switch is off when removing or replacing the control unit connector.

**** Engine trys to start but shuts off when ignition key is returned to run position ****
No voltage at plus (+) terminal of coil when ignition key is in RUN position.

Note:
The fact that the engine tries to start (fires) when the ignition key is in START position indicates that the Distributor, ECM and coil are working. It also means battery voltage is being applied to the input side of the Ballast resistor and ECM pin 1.

  1. Verify 12VDC on input side of Ballast Compensating Resistor (Connector with 2 red wires).
  2. Replace Ballast resistor.
  3. Compensating Resistor resistance value - 0.5 to 0.6 ohms
**** Engine will not fire with ignition key in either start or run position ****
CAUTION:
Make sure the ignition switch is off when removing or replacing the control unit connector. Disconnecting the plug from the ECM with the Ignition key ON can damage the ECM module.

  1. Turn Ignition Switch OFF.
  2. Remove wiring plug from the Control Unit (ECM).
  3. Ground negative voltmeter lead.
  4. Connect voltmeter positive lead to the harness connector cavity No. 1.
  5. Turn Ignition Switch to RUN.
  6. Verify voltage is within 1 volt of battery voltage with all accessories off.
    If correct voltage is present, go to step 36 (problem in wiring path to battery from ECM pin 1) otherwise continue to next step.
View attachment 857703
Click to expand...
 
Ok. At this point I do not have my positive coil wire connected to anything nor is my distributor wiring. When I put a test light on the end of the positive coil wire it lights in the run position but when I crank it, motor turns over but I loose my power to the positive coil wire.
 
Check out the drawing on the lower portion of my post. Make sure you have it wired as shown. You need to add a jumper wire from the ballast resistor to the pos side of coil. As well as the yellow wire from the starter relay. So if you do not have a dual ballast resistor and just have a single you will need a dual male spade adapter to add the coil + wire. Those terminals look like this.

615qLxr1SfL._SL1500_.jpg
 
Sadly with limited information about his setup its hard to figure out what method of wiring he has.
 
ecudia-jpg.jpg
I'm thinking your set-up is a brown wire (from ignition switch crank )here, instead of a yellow one?? In this particular schematic, to use an MSD ready-to-run, the yellow and blue wires both (tie together) go to 12v + side of coil.
 
Lefty71 said:
View attachment 857770I'm thinking your set-up is a brown wire (from ignition switch crank )here, instead of a yellow one?? In this particular schematic, to use an MSD ready-to-run, the yellow and blue wires both (tie together) go to 12v + side of coil.
Click to expand...
This is correct. Had to do this when I installed an MSD RTR in my friends GTX
 
I just had to troubleshoot this with mine a little while ago. The bulkhead connector wasn't fully seated and prevented the coil from getting 12v at crank, just like your having now.

I tested it by removing the center bulkhead connector and putting my test lead on the Q conductor and making sure I was getting 12v at crank. Then I reconnected the center bulkhead connector and tested for 12v at the ballast, which I had. Then for 12v at the coil wire (I had it disconnected for testing), which I had. Then I reconnected the wires to the coil and it fired right up.

Hope it helps!
 
BeepBeepRR said:
Sadly with limited information about his setup its hard to figure out what method of wiring he has.
Click to expand...
Hey. At this point I am not trying to hook up ecu. And I am using a run ready distributor. 2 wires coming off the distributor, positive wire going to positive terminal on the coil and negative wire going to negative post on the coil. But at this point not concerned with that. The positive coil wire coming off the ballast receives power in the run position but when I turn the motor over I do not get power in the wire anymore. All stock wiring, I have replaced the ballast resistor and starter relay. Everything worked before I put the 440 in.
 
7t500 said:
I just had to troubleshoot this with mine a little while ago. The bulkhead connector wasn't fully seated and prevented the coil from getting 12v at crank, just like your having now.

I tested it by removing the center bulkhead connector and putting my test lead on the Q conductor and making sure I was getting 12v at crank. Then I reconnected the center bulkhead connector and tested for 12v at the ballast, which I had. Then for 12v at the coil wire (I had it disconnected for testing), which I had. Then I reconnected the wires to the coil and it fired right up.

Hope it helps!
Click to expand...
Ok. Thanks. I will give that a shot.
 
You must log in or register to reply here.

Similar threads

Tony 69
Low voltage to coil
Replies
14
Views
466
RJRENTON
RJRENTON
Steve009
Msd 6AL key power, no crank power
Replies
8
Views
1K
Black_Sheep
Black_Sheep
blue69runner
No fire at spark plugs.
Replies
11
Views
712
blue69runner
blue69runner
73DreamRunner
New distributor long cranking to start up
Replies
17
Views
1K
73DreamRunner
73DreamRunner
73LemonTwist
Can Not Figure Out Why No Spark at Plugs
2 3
Replies
42
Views
2K
RJRENTON
RJRENTON
Auto Transport Service
Back
Top