AQ131D Electrical Question

"First off, I wish to express

"First off, I wish to express my gratitude that this forum exists. I have gleaned many answers over the last 2 months of searching and browsing. Now I have several questions:

Engine: AQ131D in a 1990 Renken 1700 Classic.

1) What voltage should I expect to see at the primary terminal of the ignition coil? I get around 2 to 2.5 volts less than the battery with the points closed and full battery voltage with the points open. Is that normal? I replaced the condenser thinking it was bad because of this.

2) The wiring diagram in the Clymer book I have shows a resistor feeding the ignition coil primary terminal. The exploded diagram at Volvo's website does not show this resistor. Is this resistor supposed to be there? If so, what value should it be?

and

Are these questions all answered in the Seloc manual? My Clymer manual gives absolutely no information about what voltages should be present at various points in the system for a given engine state. Nor are any resistor values given for what is diagrammed.

Cheers, Ben Wilson"

"1) That's about right

"1) That's about right.

2) No, but I believe some models had a resistor wire installed. I never used any resistor, especially since I updated to Pertronix electronic ignition.

3) No, but it is common sense and basic DC electrical theory. The coil has about 3 ohm resistance and the wire between the ignition key and the coil about 0.5 ohm. If you put both resistances in series, by Ohm's law the number of amps flowing through the wire and the coil when the points are closed should be 12/(3+0.5)= 3.43A. This means that between the coil and ground you would have a voltage of 3.43x3=10.28 volts when the points are closed, and the remaining (12-10.28=1.72V) would be the voltage between the key switch and the (+) of the ignition coil due to the wore's resistance. Of course the above values are approximate, as the battery voltage could be higher than 12V and the coil and wire resistances could be lower or higher than the ones I estimated for the calculations."

"Thanks El,

I just needed c

"Thanks El,

I just needed confirmation. I was being thrown by thinking of the condenser as a capacitor in a DC series circuit. As I think about it, the condenser must be in parallel with the points.

I was also losing confidence in my Clymer manual. Come to think of it, none of the Haynes or Chilton's books for my autos have ever had all the answers to my questions either.

cheers"