Homemade Coil Tester_How Can I Make One?

Hi! In December 1981 I went to the Gulf Outport in New Orleans to pick up a car that had been shipped from the Philipines.

The mechanic used a home made coil tester. He removed the coil from the car.

Then he attached it to his coil tester to test for a blue spark.

It had a scissors switch and some wires and a few other things mounted on a wooden board. I think it was connected to a 12 volt auto battery. Can someone please tell me how to make one or how to test the ignition coil with an VOM meter? Thanks in Advance! Any help is appreciated!

Reply to
Jim347a
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Leave the coil/dizzy in the car, make sure points/condenser is good if fitted. Unscrew the plug cap, hold the exposed HT lead aprox 1/2" away from the engine block whilst cranking the engine, should give you a nice fat blue audible spark. If not, try a different HT lead, then check with plug-cap on the lead but with a solid metal object inserted, should also give a nice fat blue spark, slightly weaker than without the plug-cap.

Failing to do so could then be: Plug cap, HT Lead, Dizzy cap or coil. The latter is very rare. You of cause eliminate faulty sparkplug before going there.

J.

Reply to
P.J.Berg

Like P.J.'s testing............but I can test for spark with a spare distributor (ground distributor). Just spin the distributor drive after you connect it to the system (condenser lead to '-' side of ign coil) and power up the coil. Use the hold the lead close to a ground.

It is easier with electr>

Reply to
dave AKA vwdoc1

Problem with using a VOM is the test voltage from the VOM is usually < 9 volts and the test current is milliamps as opposed to 4 amps or so primary current.. You may be able to read continuity of the primary, 3-4 ohms therabouts, and even the secondary but it wont show shorted turns, inappropriate flash overs becuase of the tiny voltage compared to the

10,000 - 20,000 fvolts from a coil secondary.. I,d go with what the other blokes suggest. Best tested with a dummy set up. John
Reply to
John

I would test it your way but I have one of those Tiger CDI boxes that aircooled.net was selling several years ago. I am concerned that I would fry a circuit.

Reply to
Jim347a

I had the exact same box in my -56, as long as the wiring into box, and to/from dizzy is ok you will not fry he box whilst shorting to ground.

It sparks for a longer distance and will knock you on your behind if not careful.

J.

Reply to
P.J.Berg

My grand father had a system that worked back to the Model A (and likely before) He kept a spare coil in his box. Any question he'd swap the known good to the questionable and if it started/had spark -- problem solved if not he'd check elsewhere.

Reply to
NotMe

I've heard a lot of "professional" mechanics do that. Replace parts until they've fixed the problem. at least if you do it at home you get to keep the Old (good)part. you paid for it.

Reply to
mr.smartypants

| >

| > My grand father had a system that worked back to the Model A (and likely | > before) He kept a spare coil in his box. Any question he'd swap the known good to the questionable and if it started/had spark -- problem solved if not he'd check elsewhere. | | I've heard a lot of "professional" mechanics do that. Replace parts until | they've fixed the problem. at least if you do it at home you get to keep | the Old (good)part. you paid for it.

You misunderstand the concept. It's called substitution not a matter of shot gun replacement. Old boy use that one coil for over 50 years. I still have it and the process still works. I now have both a 12 v and 6 volt coil. Gets a bit dicey on the new vehicles as they all seem to have proprietary hardware that is over priced for the proprietary nature.

As for knowing his sh|t he once disassembled an outboard motor while hanging over the transom, 10 miles off shore and basically rebuilt the motor so it ran on 3 cyl vs. 4 but it did get us home.

Reply to
NotMe

A man of knowledge and/or skill. Good man.

Randy

Reply to
rjmacres

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