coil and groud

[Tnash542]

94 ford E350 (460) c class dutchmen . i was  testing my coil today. coil has no spark . tested  the coil harness. with test light first  i tested the pos.. side  turned key to on . found good ground. touched  red side and got  the connection. then i tested the neg. side . left key on  found good pos. in fuse box  touched the neg wire and nothing. did i do this right. . how do find a ground on a wire harness. i bought a  new coil and coil wire. so my guess is there is no ground going to the coil.

 

[Mavarick]

Tnash, it?s been along time but it sounds like your hook up is correct, just the test method is wrong. To check for a negative pulse you need to hook to a hot source 12v + (like battery positive) with one end of your test light and the other end goes to the neg side of the coil (your tach wire), then crank the engine and the light should flash when it gets the negative pulse from the dist/module.

 

[bucks2]

The points or reluctor in the distributor make and break the ground side of the coil circuit. So Mavarick is correct that to find out if indeed things are working correct you need to crank the engine OR if you're just trying to find out if the coil itself works, disconnect the vehicle wiring and apply power to the positive side and then make and break a ground connection with a jumper wire on the negative side. Of course you'll need to hold the coil wire (center wire) close to ground to see the spark. Each time you ground/unground the negative side of the coil a spark should come from the coil center wire.

Ken

 

[mistere]

Do you have the ignition coil with the ignition module mounted to it?  If so, here's a web site with testing info.
http://easyautodiagnostics.com/ford_ign_fender/fender_mounted_module_5.php
If you have the remote mounted ignition module, a 3 1/2 inch square by 1 1/2 inch aluminum box, see this web site for testing the coil. If that checks ok, replace the ignition module.
http://www.international-auto.com/fiat-lancia-electrical-system/how-to-test-an-ignition-coil.cfmre
Here's a site with pictures and links.
https://www.google.com/search?q=94+ford+e350+ignition+module&tbm=isch&tbo=u&source=univ&sa=X&ei=DnLJUvbtCqbKsQS-4YDQDQ&ved=0CGMQsAQ&biw=1024&bih=680

 

[Tnash542]

Just wanted to drop a line and tell you thank you to all. We fixed it it was the coil pick up. And special thanks to member MISTERE  without your. Web links for more help. I would of cost me a fortune .thanks  going caming this weekend..woohoo..

 

[tvman44]

The electronic ignition makes and breaks the ground to create the spark.  8)

 

[mistere]

Your welcome, glad I could be helpful.

 

[Rene T]

if you're just trying to find out if the coil itself works, disconnect the vehicle wiring and apply power to the positive side and then make and break a ground connection with a jumper wire on the negative side. Of course you'll need to hold the coil wire (center wire) close to ground to see the spark. Each time you ground/unground the negative side of the coil a spark should come from the coil center wire.

Ken

Ken,
I assume what you're saying is if I remove the coil and set it on a bench next to a battery and hook up the positive battery post to the positive coil post, then the negative coil post to the negative battery post. And every time I disconnect the negative wire, and I hold the center coil wire close to the negative post on the battery, I should see a spark. Is that right"? I have one of the old style coils (1972) and I need to check it out. It goes  to a  skidsteer. Thanks.

Could I do the same thing by using a battery charger?

 

[bucks2]

Depending on your charger maybe. Some, especially those with a "start/boost" mode will act as a battery. Many smaller and generally cheaper models will not. Check with a volt meter and see if it's giving 12v on the leads.

I've never tried this on the bench. I've done it many times on the vehicle holding the coils high tension wire close to a manifold or other piece of iron. But in any event it should work. I assume you've already thought of the potential of explosive gasses near the battery etc.

Ken

 

[Rene T]

I just found my problem a few minutes ago. I cleaned (so I thought) the points in the distributor with some emery paper. Then I started checking power and continuity starting at the positive side of the coil. When I got to the points, I had no power going through them and no continuity. So I took a small flat file out of a jewelers set I have and filed them a little. VOILA!! I now had continuity and power when I turned the key on. I hit the starter switch and it turned over I revolution and fired right up. What a sigh of relief. Thanks for your input Ken. I now know how to at least test the coil if need be in the future.

As far as my charger, it's about 45 years old. I checked the output and it's just a little under 12 volts. It probably getting tired but it still does work just not as good when it did when it was new.

 

[bucks2]

Success! Cool.

Ken

 

[John From Detroit]

Reminds me once of my brother, who was studying to become a mechanic (And as it turned out a good one eventually both Diesel and Gas, then he took up driving the things instead of fixing them)

He did an overhaul on a Ford Tractor we had (Gas) and it would not start, We suspected ignition issues so I got out a multimeter and quickly narrowed it down to the points... He ask how much that meter cost me (About 8 bucks as I recall) told me they had one back at school, only cost about 1500, did the same job.

What can I say, the one at school had a brain to interpret the results.. I had one of those too, only mine was NOT part of the meter.