Crank , no start question

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thechamp

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My 16 year old sons 71’ Demon 340 new build. Finally after 3 years it was time to fire her up tonight and it turned into a parts Change out pretty quick. Everything on the car is new, except the harness. It will crank but not start, it did fire and run for about 3 seconds one time. It had intermittent spark, now has no spark. While trouble shooting I did notice with the coil white off the distributor.. when you turn the key to the on position it will spark one time then will not spark while cranking. Tried 2 coils, 2 ignition boxes, 2 voltage regulators,2 distributors, with no progress. I have voltage to the coil, voltage on both sides of the ballast resistor.
I do not have the gages in the car and have the wires to the alternator gauge jumped together. Please help me out to trouble shoot the next thing. If your suggestion is the ignition the switch, let me know a way to temporarily bypass or check that before pulling the colum again.. thanks everyone in advance!

IMG_3450.jpeg
 
The ignition switch has 3 terminals to start and run the engine.

IGN 1
IGN 2
S

IGN 1 provides power to the coil and ignition box with the key in the run position

IGN 2 provides power to bypass the ballast resister and is only powered during cranking

S provides power to the starter relay to crank the engine.

All 3 are separate circuits.

IGN 1 does not have power while cranking.

So it kind of sounds like you don't have power to the coil and ignition box during cranking.

You can hotwire the car by running a jumper from battery positive to the coil positive, and to the power input to the ignition box.

There are lots of other reasons it would not fire, like timing, distributer issues.

But the jumpers would be a quick check
 
I Always have a point distributor lying around for this reason. The aftermarket boxes and or old boxes can give you fits.

Look up the mid 70's Chrysler electronic ignition wiring diagram off the web and make sure that your in compliance (there are two different systems 4 wire and 5 wire), then take a jumper and go from the positive post of the solenoid to the feed side of the ballast resistor and see if she'll light off.

Okay, she runs. Now run a 8/10 gauge fused wire from the positive post on the alternator to the positive post on the starter relay. Remove the jumper and see if she'll fire.

Yes, its your charge gauge and or bulkhead.

No, look at your ignition switch wiring and the bulkhead.
 
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What is troubling me is that it did start and run for about 3-5 seconds. Now while cranking I’m not getting spark. I was initially out of time 180 and corrected that and it fired right up, then after a little more fuel in the bowl tried again and now no spark
 
thechamp said:
What is troubling me is that it did start and run for about 3-5 seconds. Now while cranking I’m not getting spark. I was initially out of time 180 and corrected that and it fired right up, then after a little more fuel in the bowl tried again and now no spark
Click to expand...
The engine is at tdc on #6 with the cam installed to aligning marks on a fresh build with your dampener at TDC.
 
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So you're trying to start the engine with no cooling system? Why?
 
Illahe said:
I Always have a point distributor lying around for this reason. The aftermarket boxes and or old boxes can give you fits.

Look up the mid 70's Chrysler electronic ignition wiring diagram off the web and make sure that your in compliance (there are two different systems 4 wire and 5 wire), then take a jumper and go from the positive post of the solenoid to the feed side of the ballast resistor and see if she'll light off.

Okay, she runs. Now run a 8/10 gage fused wire from the positive post on the alternator to the positive post on the starter relay. Remove the jumper and see if she'll fire.

Yes, its your charge gauge and or bulkhead.

No, look at your ignition switch wiring and the bulkhead.
Click to expand...

RustyRatRod said:
So you're trying to start the engine with no cooling system? Why?
Click to expand...
Just initial fire to make sure things are working correctly before installing the remaining components. If something was very bad it would all have to come back out
 

Check the pick up has not moved or is out of adjustment. Should be 0.008".
 
thechamp said:
Update… engine will fire if I jump pole to pole on the ballast resistor
Click to expand...

Sounds like an ignition switch or the wiring between it and the ballast resister.

To test...

Remove the yellow wire from the starter relay.

Turn the key to the start position

With the key in the start position check for voltage at the coil, in start it should be near battery voltage.

With the key in run it should be less than battery voltage.

If in the start position you get less than battery voltage the same as in run the ignition switch or the wiring between it and the coil positive is the issue
 
Dana67Dart said:
Sounds like an ignition switch or the wiring between it and the ballast resister.

To test...

Remove the yellow wire from the starter relay.

Turn the key to the start position

With the key in the start position check for voltage at the coil, in start it should be near battery voltage.

With the key in run it should be less than battery voltage.

If in the start position you get less than battery voltage the same as in run the ignition switch or the wiring between it and the coil positive is the issue
Click to expand...
 
I quoted the paper thickness so the OP would know pieces of paper needed.....dummy.
 
Bewy said:
I quoted the paper thickness so the OP would know pieces of paper needed.....dummy.
Click to expand...
You hush up. Your toilet don't even flow the right way. ..that's kinda like your elevator don't go to the top floor. lol
 
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