I need help interpreting vacuum test results

[Dragon]

Almost there after the resistor is fixed swap in another coil and give it a shot.

[HOWDY69]

Thanks for the support. I am trying to decide if I want to stand on my head in the cab tonight or tomorrow morning before work. I have a dealer installed AC system which makes the wires harder to get to and reduces the space for my head and arm. They are predicting rain in the morning. I guess I will eat supper and then decide.

Again...thanks for all the help.

[Dragon]

Your Welcome

[HOWDY69]

I bought a new Flame Thrower 1.5 Ohm coil. If I am reading the directions correctly I should be able to put the new 12 volt lead (from the red/green wire) and the red wire for the Ignitor on the positive coil screw. The black Ignitor wire would go on the negative coil screw. I will then tape up (cover the hot connecter on) the old coil wire and leave it in place in case I need to reinstall the points at some time. Also I will disconnect the wire from the starter relay “I” terminal and leave it in place again in case I need to use the points to get back to civilization. This will eliminate the resistor wire and the starter relay from the ignition system.

The fellow at my local speed shop said he has not heard of an Ignitor returning from the grave so he agrees the most likely culprit is the coil.

Edit: But wait…if I do this will the truck start? It will have power in run mode but how about start mode?

[Dragon]

Don't change your working wiring put the coil in exactly the way you took the old one out. Your old positive coil wire to posi on the dizzy and the black wire to negative. The reason we have different wires feeding the coil is when the starter is turning the voltage on the coil wire drops so we steal power from the solenoid to fire the engine at full voltage.

[HOWDY69]

Don't change your working wiring put the coil in exactly the way you took the old one out.

OK...the way I had it (since the rewire last weekend) was old coil wire which included resistor wire to coil and new hot wire from before resitor wire to Ignitor.

Your old positive coil wire to posi on the dizzy and the black wire to negative.

Instead of dizzy do you mean coil?

The Flame Thrower instructions say to refer to chart on back of instructions.
The chart says "1.5 Ohm Coils...8 cyl. all aplications...remove resistor"

This would be Figure 2 on the Ignitor instructions.

[Dragon]

I meant coil and unless they have improved the coil I fried one removing the resistor. What is your coil number?

The only one they show with 1.5 ohms is not supposed to be used with the ignitor I or II. http://www.pertronix.com/prod/ig/flame/coils/chart.aspx part number 60115

[Dragon]

Their web page and their catalog conflict each other. Okay the wire that feeds the ignitor can also feed the coil. You will still need the start wire from the solenoid to go to the coil. For cold starting.

[HOWDY69]

There is something that still bothers me. When I remove the old + coil wire from the coil and read the voltage in run mode it reads 12 volts. How could this be if the resistor wire is in play? A cold wire has less resistance but would the resistancxe of the wire at 50 degrees be this low?

[Dragon]

Well a 1.4 ohm wire is not going to drop more than 1 volts depending on the circuit resistance. A resistor should not drop any part of an ohm until it is supercooled, you know like -436 degrees

[HOWDY69]

OK...I put everything back the way it was when the truck died last Sunday. I connected the old coil wire with resistor wire to the old coil and new wire from the red/green wire to the Ignitor. Then I took the following readings:

12.6 volts Battery with key off
12.3 volts Battery with key on
14.2 volts Battery while running

Then I started the truck and took readings every few minutes for 15 minutes. The readings did not change much over 15 minutes:

11.8 volts (+) coil terminal
14.0 volts (+) Ignitor wire

The readings jumped around a bit but would stay on the above readings 90 percent of the time. I guessed the jumping was because the system is actually dynamic as the current stops and starts.

It looks like the resistor wire is knocking the voltage down from 14.0 to 11.8.

Is there a problem with the voltage regulator or is there supposed to be 14 volts at the switch?

[Dragon]

13.8 - 14.2 maybe 14.3

The battery is 2.2 Volts per cell when new with clean electrolyte 2.2 time 6 is 13.2 Well it is on brand new never run batteries in the factory. They lose some voltage storage on their first charge. That is the key off voltage you read. If the Alternator was to charge at 12.6 the battery would never charge. It cannot over come the voltage coming out of the battery to put voltage in. So the Alternator must charge at a higher Voltage than the design of the cells 13.2 and that is why the regulator puts out higher than 13.2. The alternator charges backwards to charge the battery. It puts higher positive in on the positive terminal to force the chemical action to flow backwards and reset the electrons to the proper plate.

Once a car is running most times they run on the alternator only, the battery is along for the ride. Now you turn on the 500 Watt amp and the 8 300 watt lights on the roof at the same time and the battery fills in for part of a second until the alternator and regulator catch up. If you are idling with a 65A alternator you will probably see the engine slow down a few rpm.

[HOWDY69]

So the voltage looks good? The Ignitor is rated to 16 volts. What about the coil? Can it handle 11.8? I keep reading that the purpose of the ballast is to knock 12 down to 9 but mine is knocking 14 down to 11.8 and this is at idle. I also read that modules are susceptible to voltage spikes on the back (black) side. The Voltage on the (-) coil terminal jumps around but I did read about 3 volts a few times.

I am going to put in the new coil and retest.

[Dragon]

So the voltage looks good? Can it handle 11.8? I keep reading that the purpose of the ballast is to knock 12 down to 9 but mine is knocking 14 down to 11.8 and this is at idle. I also read that modules are susceptible to voltage spikes on the back (black) side. The Voltage on the (-) coil terminal jumps around but I did read about 3 volts a few times.

From the top your coil will live. Shoot the more rpms the more voltage the coil needs to get charged in time anyway.

On the back side they mean don't run the spark plug wires and the black wire together, don't short the black wire to ground when on.

You would need to spend about 439 dollars on a fluke like mine to see the voltage on the negative side. it jumps because it is switching the coil off and on when running. At 1000 RPM it switches on and off 500 times in a minute or 8.33 times a second. Too fast a transient for the meter to lock on to. My meter in averaging mode will show about 4 volts. When the coil is charging the voltage is low when the points or module are shorted the coil is absorbing the voltage and rising up towards the input (positive) voltage when the points or module opens the voltage no longer travels on that wire because it has no place to go.

The positive wire is no longer shorted to ground through the primary windings and it travels up the high tension lead instead of the coil primary windings. The primary winding voltage and stored energy drops and transfer via the magnetic field to the secondary windings and out to the plug.

[HOWDY69]

I installed the new Flame Thrower 1.5 ohm coil and drove the truck for about an hour. I was unable to get it to die (yeah). The voltages after it was all warmed up were 11 at the coil and 14 at the Ignitor red wire. The restor wire was warm to the touch but not to hot to hold.