1973 Plymouth Fury 360 Crank, No start

[The_Eagles’_Nest]

So after getting the intake and carburetor back on my Fury, I went to fire it up and it was extremely hard to start. The carburetor is set correctly and everything was installed properly. Tons of photos were taken to make sure everything was installed as it was.

After a couple of days of tuning, the car was still hard to start and eventually stopped running with stalling randomly. No it will not start at all, no spark. I checked the voltage in and out of the ICU, it was 11.5v in and 6.73v out, and 6.73v at the coil. So I replaced the ICU and it started again, but hard and would be near impossible to start when hot.

Now with a new ICU, new voltage regulator, and a new alternator it will not run at all. It will crank, but back to no spark. I tried again today to get it going.

The coil is at 6.79v and with the ICU unplugged it is 12.29v with the ICU and voltage regulator unplugged it is 13.11v.
It still has no spark at the coil even with two different coils.

The cap and rotor are new, spark plugs, spark plug wires are new and in the correct order, the ballast resistor tests good, and still no difference with multiple ICUs.

Measuring from the ICU to ground with the key on I get 12.29v

Measuring from the coil to ground with the ICU plugged in 6.67v and ICU unplugged 12.53v

So some how I’m getting a 6v drop between the coil and ICU, and no spark at the coil tower.

 

[71Newp]

A bad ground for the ICU? Is the surface where it it mounted free from rust/gunk/grime? Good luck!

 

[The_Eagles’_Nest]

A bad ground for the ICU? Is the surface where it it mounted free from rust/gunk/grime? Good luck!

I have covered the basics. It has a clean ground. No difference.

 

[WOT440]

Switch to Pertronix. Modern Chinese manufactured ICU's are not dependable. IMO.

 

[The_Eagles’_Nest]

Switch to Pertronix. Modern Chinese manufactured ICU's are not dependable. IMO.

It’s factory electronic ignition, I can’t swap it to Pertronix.

 

[Dano1973]

Did you replace the starter relay

 

[The_Eagles’_Nest]

Did you replace the starter relay

No, starter relay is fine.

 

[Dano1973]

I'd check the pickup in the distributor

 

[The_Eagles’_Nest]

I'd check the pickup in the distributor

I had a brainstorm overnight and thought about it. A new distributor is here in 4 days.

 

[Dano1973]

More than likely your issue

 

[The_Eagles’_Nest]

Even a new distributor did not get it running! I’m amazed. It must be a wiring issue then.

 

[Dano1973]

Might be the fuse able link on the drivers side inner wheel well check it out

 

[The_Eagles’_Nest]

Might be the fuse able link on the drivers side inner wheel well check it out

It is not, they are both good.

 

[Dano1973]

Try voltage regulator

 

[The_Eagles’_Nest]

Try voltage regulator

Already did, no difference. Sounds like spitballing.

 

[Kaim]

Are you sure the air gap between the pickup and the reluctor teeth is 0.008"? Was it OK at all on the new distributor?

 

[Dano1973]

I'd say bad pickup on your old one

 

[Kaim]

Quite often the reason is in the pickup.....

 

[68yourker]

What are the voltages at the coil positive with the key on and the car cranking? And what is the voltage at the battery while cranking? These cars have a ballast resistor bypass system in the starter relay during cranking. This will give the coil more volts during cranking to provide a nice hot spark for starting. That circuit is disabled the moment the key is returned to the run position. So during cranking the positive side of the coil should be very close to battery voltage. HTH