To check for vacuum leaks all you really need is a spray bottle of water. With the engine warmed up and idling spray lightly around the carb base, the intake manifold and any other places you might suspect of leaking. If you find a leak the engine RPM will pick up a little. Some guys like to use WD-40 for this or even carb cleaner. The problem with that is any overspray will be sucked into the carb, causing the RPM to increase and give you a false indication of a leak.

Thanks again for all of the contributions to this thread.

Today I reversed the plus and minus wires at the coil, used the remote starter switch so I could manipulate the throttle and the distributor and had the engine running in 30 seconds!!!   Apparently I had accidently switched them when I changed coils right after this whole mess started several weeks ago.  Backed off the curb idle screw to about 600 RPM, rotated the dizzy a little until it smoothed out, adjusted the mixture screws a bit until the vacuum gauge steadied at 20 inches and tach settled down at 500 RPM.

I want to check for any vacuum leaks around the carb and intake but don't know how that is done.  Help there will be appreciated.  I will also recheck the dwell and the timing with a light.

Maybe I got it!!  Test drive tomorrow....

Regardless of how the coil is connected, it should still start, and run. See the link below that explains how this works. Be careful when cranking the engine over trying to get it to start, engine starters (and starter relays, wiring etc) are only capable of a limited duty cycle. They will be permanently damaged by extended cranking (just a few seconds) without long cool down periods. Ordinarily a well tuned engine will start in just a split second. That's how engineers were able to get away with undersized starters and relays, they are not called upon to run for long periods of time. Don't roast your starter during the troubleshooting!


Ignition Coil Polarity : https://mgaguru.com/mgtech/ignition/ig104.htm

You can also check spark (ignition coil) polarity using an analog (moving needle) volt meter. Hook up a voltmeter with the negative lead to the plug terminal and the positive lead to the block. Set the meter on the highest volt range. Crank the engine over (no need to start it), and you should see an upward swing of the voltmeter needle (don't be concerned with taking a reading). If the needle swings down off the scale, your coil is hooked up wrong. To correct it reverse coil primary leads. Do not worry about the coil markings, but make note of them for future reference.

If an ignition coil has been connected "wrong" for some time, it may even be slightly damaged as far as spark output is concerned even after the connection is swapped. They utilize an iron magnetic core. But again this is probably getting off into the weeds a bit. It is unlikely this is the cause of the Unpeasantness. The test described above though, is very quick and easy if you want to be sure.

Thanks again for all of the input.  I will switch the plus and minus wires on the coil while I charge the battery, too much cranking lately.  I live in a very small northern Idaho town and there are no ignition specialists except for old hot rodders that may live in the area.  Maybe I can locate one?

I tested for crossed wires on the driver side using my "spark tester", first checking for spark at #5 (yes) and then pulling #5 wire at the dist. cap and checking again at 5 (no).  Did this for #s 6, 7, and 8 and all three checked out OK.  I, too, had read about the factory seperator bleed-thru issue and will peek down behind the block in the dark if I can get it running again.  Maybe there will be enough "leakage" that something will be visible.

At this point I would look for an ignition specialist in your area. If your not a member of a local old car club you might seek one out and check with the membership, car shows are a great place to start. Electrical, and especially ignition problems, usually are a nightmare for the average person. In your case I would seek out professional help, life’s too short. Replacing your entire ignition system might not be a bad idea and having the car converted to 12 volt a better one, oh and insist on top of the line Taylor spark plug and coil wires. I’ve been stranded do to ignition failures on more than one occasion, once due to a new China made ballast resistor, (hesitation and backfiring thru the carb) and a second time caused by a new Mallory (China made) condenser (same symptoms as resistor).

In my education from bad experience I now have a new distributor and a completely electronic ignition system, no more points, condenser or ballast resistor. Life is once again good 🚗

1955 312 T-Bird Warwick, NY

The fact that you saw strong sparks from your plug wires to ground I wouldn't focus on your coil or condenser. I remember there was a factory notice about cross firing on y-blocks discovered to be from a bad placement of the plug wires in the loom's grommets. They provided a diagram of a different placement of the wires to correct the problem. Cross firing is the result of inductive coupling from a wire beside an adjacent wire which can result in the ignition pulse going to the wrong cylinder. I've been looking for the book I saw it in but I'm having trouble finding it. I saw it in a book from a Tbird club that had a collection of factory fixes. Maybe somebody can recall and come up with diagram, meanwhile i'll keep looking

An (analog preferred) ohmeter can tell you a little something about whether an ignition condenser "should" work or not. But that's it. It will "charge up" and tend towards infinity. Keep in mind ignition condensers (and coils) must always be tested at normal operating temperature. Makes sense, no?

Ignition service is rough duty however, a full test requires about 500 volts DC. If your condensers in question are el-cheapo no name parts sourced from you know where (if they are anything other than OEM or similar) ignition parts I wouldn't even bother. Most people don't have test equipment to do this properly, so you're still at a guess and by golly.

The proper ignition coil polarity connection actually has nothing to do with whether the vehicle is positive or negative ground. They will work connected either way, but the spark output at the plug itself will be attenuated by about 25% if it is connected wrong. The problem is some coils have a different internal connection, coils intended for other applications. It just gives me a headache trying to think about it..

It is possible, thankfully to check for correct polarity ignition coil connections with an analog voltmeter, or you can try the "pencil test".

We made that mistake on a friends 52 Willys that was positive ground, switched the wire around and then it ran fine. I won't tell you how long it took us to figure out our mistake LOL. I would try switching the wires..

Hey, its me again.  Maybe I dummied up...  When I changed coils several weeks ago I connected the ignition wire to the + terminal and the black distributor wire to the     -  terminal.  Inasmuch as this is a positive ground application are the wires reversed on the coil???

I have attempted to check numerous condensers but I have failed to understand how to test them using my anolog multi-meter.  Mostly because I don't have a good grasp of how to use the multi-meter anyway!  Can someone give me very basic instructions on how to set up the meter and what to look for on the ohn scale in regard to resistance?    To date I have read where the red and black leads are to be plugged in, that the ohm switch should be set in the highest position, that the dial pointer should be zeroed out,  and that when touching the leads to their respective +  and - positions on the condenser the pointer reading will tell me whether or not the condenser is good.  The pointer swings clear to the right side of the dial on some condensers and ranges around 50 - 70 on the others.  However, I do not know how to interpret the reading.  Also, I have attempted to use my 7-function digital multi-meter but it baffles me more so than the anolog meter. 

I could be mis-remembering, but it seems to me that spiral wound (and solid core) plug wires can be checked with a "beep test" continuity on a digital VOM.

Carbon core plug wires are a bit different, this won't work. So it's not as handy to check, but they will of course show resistance on the meter as Hoosier Hurricane mentions. So you could check that way, just not audibly.

Another method might be to (for example) pull the #1 plug wire boot at the plug, and install a spare spark plug and ground it. Turn the engine over both with, and without, the #1 plug wire end installed at the distributor cap. If it sparks, then that wire is installed correctly. If not...

It's sort of strange but depending on what (cylinders) plug wires are switched, it won't seem to necessarily idle too badly. Great way to get that "Lopey Cam" sound!

Sure, way down on power, backfires, but a lot of non-mechanical type people don't pay much attention. After studying some of the automotive forums for a while, maybe it isn't common to have plug wires out of firing order, but it sure isn't unusual. Of course this may not be the problem - but it's most definitely among the first things to verify.

More than one person has sold a car thinking it was unrepairable, because of this defect, and they were not happy to see the new owner drive away laughing his ass off. Oops!