coil resistor question

[Maikl]

Hi there,

in my never ending search for the source of my idle problems, I now installed a new coil resistor.
When I had the starter doing a couple of turns to flood the also new fuel pump, I sensed the smell of hot/melting isolation. I shut off electricity and found that the coil resistor became pretty hot and emitted this smell.
As I do not consider connecting a resistor to be a fruitful source for making mistakes, I wonder, whether this smell is normal for a new resistor and if high temperatures are common to occur while you engage the starter ?

Or is there a catch to connecting a coil resistor ??? (Does not make any difference, which cable goes to which terminal, does it ?)

Thanks for any input...
Maikl

[rcull]

resistors build heat. It shouldn't smell after a while. It doesn't matter which terminal. The resistor should be bypassed while cranking the starter. During start, there should be 12V to the coil, during run the reduced voltage.

[Flynbuick]

I do not see any way this could be the source of your idle issues. It is more likely that you need a carb rebuild or that you have a vacuum leak in the engine.

[Maikl]

resistors build heat. It shouldn't smell after a while. It doesn't matter which terminal. The resistor should be bypassed while cranking the starter. During start, there should be 12V to the coil, during run the reduced voltage.

Thanks rcull,

actually that's what puzzled my: The resistor should be bypassed while cranking but did get hot in my case
I guess, I will have to check the bypass-line for good contact then and check voltages...

Take care
Maikl

[Maikl]

I do not see any way this could be the source of your idle issues. It is more likely that you need a carb rebuild or that you have a vacuum leak in the engine.

Thanks Flynbuick,

problem is: I am through all this already (carb is rebuilt, possible vacuum leaks have been extinct).
I was not able to determine any pattern in the behaviour of my car so far. Sometimes idle is okay, at another time she dies on a traffic light... Somebody gave me the hint to replace the resistor after 52 years, as it influences idle and low speed operation...

Best regards
Maikl

[njlimbaugh]

How is your wiring? If you have a bad or loose connection in the circuit or a badly worn ignition switch or a wire halfway worn through you could be building up resistance somewhere other than the resistor (which you've replaced anyway). I've found over the years that the best thing you can do for an old car is rewire it. I suggest checking the ignition circuit with an ohmmeter. It's possible that the contacts in the ignition switch are badly worn due to the age of the car. You should have zero resistance through the switch.

[Maikl]

Hi everybody,

I am amidst testing the ignition circuit and found one condition of which I am not sure if it is normal:
With ignition turned on and ignition coil diconnected: Between the +-side of the coil resistor (pink cable coming from ignition switch) and ground I measure a resistance of ~100 Ohms.
Is there any circuit closed via the ignition switch in this condition that would allow this condition Should the ignition circuit not be totally cut off ground when coil is disconnected ?

[1946_HoldenBody]

Sound to me like the pink wire is a resitor in itself. This was the case with many cars from the fifties right up until fuel injection took over Resistor wire from the ignition switch to the coil + is a common thing for GM. It is usually pink with small black writing on it. If you are looking for a stalling problem I would be checking to see if your distributor advance is operating freely. Sometimes the centrifical advance weights can stick slightly out, or the return springs can be the slightest bit loose, so that the distributor has a two or three degrees of advance pretty much all the time. Sometimes the weights will go all the way back to zero and the resulting lack of advance will kill the engine. This usually happens when you slow down on the gears pulling to a stop, as the wheels driving the engine against a closed throttle causes extra fuel to be sucked in through the idle circuit, slightly flooding the engine. WIth a couple of extra degrees of advance on board the engine copes, but if the timing drops back a few degrees the engine stalls. Many cars of the sixties had "anti stall dash pots" fitted to the throttle linkage that held the throttle open a little for a second or so, to prevent the flooding on the over-run.

Check your distributor advance weights are operating correctly and test the theory by adding a couple of extra degrees of advance.

[Maikl]

Thanks for the input !
1956 Buicks have this dash pot, too.
But I will check for what you described anyway...