How to test a Condenser

[cudaken]

As some of you may remember I have a 68 383 Road Runner that is not stock. It sat for 8 years then I got her started! Sounded great, would sit me back in the seat ! I was very pleases to have Miss Lumpy running again!

One day I wanted to play with her and went to start her, all she would do is crank? I know I have compression and had gas. So the problem must be the coil, points, or condenser. I have power to the + side of the coil as well and ballast resistor is by passed till I get the repaired wiring harness back in the car.

I replaced the condenser once and still no fire / hit. Replaced the coil and still no luck. Then one night I saw this bare red wire in the distributor so I am 95% sure that is the problem!

http://s83.photobucket.com/user/cudaken/media/Charger%20Site/1-12-27002_zps638b588d.jpg.html]

I have the distributor out, pulled it apart and the rest of it seems to be fine. So after the wire is fixed I should be good to lite the hides!

But, I all so know new parts can be bad! So I want to check the old and new and old condenser. I did a U Tube search and found this.

https://www.youtube.com/watch?v=FDuN7QHn1-s

I know the condenser is just another word for capacitor. So if I ground a led from my meter to the body of the condenser and other led to the wire will this test work?

Thanks for the coming answers, Ken    

[A383Wing]

if that bare red wire is touching ground anywhere, the coil will not fire.....that is a direct short to ground for the coil.

to answer your original question, you can test the condenser by charging it from the battery, touch the wire lead to positive and the body to ground......then touch the wire lead to the body of the condenser, it should make a small spark.

[Pete in NH]

Ken,

The capacitors in that video were bigger than the capacitor in your ignition system and would hold a charge long enough to get a reading on the meter. The capacitor in your ignition system is much smaller and you may not see a meter reading.

383wings  method might work but again the capacitor is on the small side and the stored spark might be really small and hard to see.

An older analog ohmmeter with a needle pointer works best for this kind of capacitor testing. If you touch the capacitor lead to the capacitor case to first discharge it, the put the black meter lead on the capacitor case and then touch the red meter lead to the remaining capacitor lead you should see the meter needle "kick" as you touch the leads together. I would try this with the meter set to the R X 100 or R X1000 scale. Digital meters are too slow to see the kick. If the meter kicks the capacitor is likely good. You can repeat the test by shorting the capacitor to its case and doing the test over.

[John_Kunkel]

Yep, this is one case where an analog multimeter trumps a digital.

[flyinlow]

Here's how to test it. 

Pull a plug wire off a car that runs. Ground the body of the condenser . Hook the plug wire to the condenser and start the car to charge the condenser. With insulated pliers set the chargered condenser on a work bench with a dry rag under it. Then ask your buddy to hand it to you.  If the condenser is good, his reaction will confirm that it can hold a charge.

[cudaken]

Here's how to test it. 

Pull a plug wire off a car that runs. Ground the body of the condenser . Hook the plug wire to the condenser and start the car to charge the condenser. With insulated pliers set the chargered condenser on a work bench with a dry rag under it. Then ask your buddy to hand it to you.  If the condenser is good, his reaction will confirm that it can hold a charge.

Will that will be the last time Allen would ever trust me, assuming he still does!

Pete, I do have a digital meter, to bad I don't have a old style. I hate electrical problems, I am half way clues less. 

Byran and Pete, do you think that I could test it Bryan way with a 9 volt battery?

Stupid Ken

[Pete in NH]

Ken,

That 9 volt battery and small capacitor will not really give you a spark you will be able to see.

You might try the following- Set your meter to a range that will read the 9 volt battery. Put the black meter lead to the negative side of the 9 volt battery. Put the red meter lead to one side of the capacitor. Put the other side of the capacitor to the positive side of the battery. If the capacitor is good, the meter will start at 9 volts and work it's way down to zero or very, very, close to it.

To do the test over again, disconnect the capacitor and touch the two capacitor connections together. This will discharge the capacitor and you can repeat the test if you want to.

[A383Wing]

how come you don't just fix the little red wire and buy a new condenser? They are only a couple bucks from NAPA

[flyinlow]

While a condenser with broken down insulation will short the ignition out ,I don't remember having many problems with them. I left the old ones in during point changes most times. One less small screw to drop in the distributor. Points on the other hand where problematic. Sensitive to oil or grease on the contacks. You could look at then the wrong way and they would burn. Always carried a spare set.