Still can't figure it out.........HEI

[1carlover]

I posted last week about an electrical issue I was having with my 67 Coronet rt and was able to get it resolved with the gracious help of nm9stheham. Thanks Mark for taking the time. The problem I am having now is that the MSD High vibration blaster coil is not sending 12v to the ready to run HEI Mopar distributor that I purchased through White Performance. I have bypassed the ballast and am getting battery voltage of 12.8v to the positive side of the coil when the ignition key is in the run position. When I crank the engine over I am getting only about 1.5v from the coil. I seem to be missing something here and have run out of ideas. Any help would be appreciated.

 

[Hemi Rebel]

I looked up the distributor. You should have two wires from the distributor to the coil. One to positive and one to negative. You should have 12v from ignition switch to the positive side of
the coil. In start and run. If you dont have 12v in start then you need to

 

[1carlover]

H.R. That 2 wire setup is what I have and I'm getting 12v to the + side of the coil. Last week I replaced the ignition switch to rule out a possible problem there. The starter engages as it should when the key is turned. Where has the 12.6v gone?

 

[Hemi Rebel]

From the back of the switch you should have battery voltage on one of the terminals in start position that originally went to the ballast. How did you eliminate the wiring to the ballast resistor?

 

[1carlover]

I soldered a jumper wire and connected the terminals of the ballast. I have 12.6v at the blue wire terminal on the BR.

 

[Hemi Rebel]

I soldered a jumper wire and connected the terminals of the ballast. I have 12.6v at the blue wire terminal on the BR.

You jave 12.6 with the key in the run position? But not start? You need to trace the other wire back to the ignition switch. Pay close attention to the fire wall connection.

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Im trying to study what wiring I can find on Google

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You should have 12v on the brown wire with key in start position. This wire should be in one of the terminals that went to the ballast it is joined in the connector with a dark blue wire.

 

[1carlover]

Yes 12.6v in run and start at the BR. The ignition and foreword light harness are new from year one and the dash harness was a clean uncut unit purchased on this website. The bulkhead connectors are in good shape and the wire connection to the ignition switch also looks good. There is no corrosion or oxidation or blown fuses and all ground wires with the exception of the dash ground wire which I disconnected from the back of the dash assembly before I removed it. The red and black wires from the amp gauge have been connected to complete the circuit.....and I thought if I replaced the original wiring I would avoid electrical problems.

 

[Hemi Rebel]

Oh, 12.6 in run and start at br, but when cranking it pulls low. Sounds to me like that would be in the distributor. Remove the positive wire to the distributor at the coil. Leave the power wire from ignition to the coil positive and see what the voltage does when cranking

 

[sleepar]

...........

 

[1carlover]

I have 12.6v going to the coil but its not energizing the coil. I'm getting 12v from the battery at the blue wire at the BR which energizes the ignition until the motor starts and the alternator feeds 12v back through the blue and brown to the voltage regulator and back to the battery.

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Will check that out now

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HR Having a little difficulty checking this out as my darling wife fell asleep and I wont have anyone to turn the key until tomorrow. Im calling it a day too and will check in the am to see if you are still online. Thanks for the help. Carl D.(1Carl Over).

 

[Hemi Rebel]

With the key in the run position, current flows from the ignition switch to the voltage regulator, and from the VR the blue wire goes to the BR. Now if we look at the system as if it were set up 100% factory, current would flow through the BR where it would then meet up with the brown and blue wire connector, and would take the blue wire to the positive terminal on the coil.

Has the car yet to fire? if not, the first thing I would do would be to eliminate the blue wire from the positive post on the coil. Just take it off and secure it so it doesn't touch anything. Then I would run a jumper direct from the battery positive to the coil positive and start the engine. If you get soark w need to go back and look at the wiring in the car to figure out why the voltage drop.

 

[1carlover]

HR good morning. I've tried to keep this car as original as possible with one exception being the ignition. The motor has not yet been fired since the rebuild. I'll run the jumper wire to the positive coil in a few and see what happens.

As I was testing voltage at the BR I then ran a jumper from the blue and brown wire to the + side of the coil. I had 12.4v in the run position but when I tried cranking the motor I got a fluctuating 9.6v at the coil. I then removed the jumper wire at the coil and got the same reading of 9.6v. Maybe the voltage regulator is the problem here?

 

[1carlover]

Voltage regulator checked out ok.

 

[sleepar]

Corrosion at the bulk head connector or worn out contact in the switch.... somewhere something is not making full contact or a wire has corrosion from a pin hole inside the wire.... it's frustrating take a step back and do something else and come back to it...

 

[1carlover]

Frustrating to say the least. Engine bay wiring is all new and I installed a nice uncut harness in the dash just to avoid this sort of thing from happening in the first place. Ignition switch, VR, alt, starter and relays all new too. Looks like Im going to have to dig a little deeper.

 

[sleepar]

New comes junk from the box today... have an old switch to try? I'm redoing everything also but I know their will be something.... there always is.. if it all works right the first time it would be rare...