P-12 Tommy Posted June 1, 2011 Report Posted June 1, 2011 Hey guys, Just when everything's running great, something's got to screw up! I've been driving the P-12 on a daily basis. I went to a CVS drug store earlier and the car died as I pulled into a spot. I tried to crank it back up and it didn't even try to fire. I popped the hood and checked the carb for gas and I'm getting plenty. I pulled the coil wire and cranked it from under the hood with the key on and no spark. I walked home (only a mile) to get the other car. I brought my olm meter and test light to check the coil. I tried starting it then and still no fire. The test light wouldn't even light up when I touched the coil terminal. (with the key on of course) I checked with the meter and came up with between 0.06 to 0.10. Not even a volt! Remember I got the firewall coil with one terminal. What's the minimum output that'll make it run. The ohm meter should say 6 volts, right? Sounds like it crapped out. BTW... it's gonna be fun getting one of those coils in a hurry. Thanks for any help(as usual), Tom Quote
Merle Coggins Posted June 2, 2011 Report Posted June 2, 2011 Your Volt meter should show 6 volts IF the points are open. If the points are closed, or there is a short to ground somewhere else, you won't read any voltage on that terminal because it's grounded. Try it again with the cap off and use a screw driver to manually open the points, or disconnect the wire from the distributor and see if there's voltage there then. If not then it could be a bad coil or it could be a problem with the ignition switch or the power feed to it. Good luck, Merle Quote
Joe Flanagan Posted June 2, 2011 Report Posted June 2, 2011 I had no trouble finding a 6 volt coil at my local Auto Zone. They got air fresheners. They got fuzzy steering wheel covers. And 6 volt coils. Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 Thanks Merle, I'll check that. Joe, Auto zone doesn't carry my coil. I got the firewall one. Tom Quote
JIPJOBXX Posted June 2, 2011 Report Posted June 2, 2011 (edited) I used the two pole on the top of coil and replaced the one that had the one wire on the bottom. It was fairly simple and I also used that if you want to the can that held the old style in place. Jon Edited June 2, 2011 by JIPJOBXX Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 I suppose you can run the wire in the conduit from the ignition switch to one side of the coil and have the other one go to the dizzy. Right? Tom Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 I used the two pole on the top of coil and replaced the one that had the one wire on the bottom. It was fairly simple and I also used that if you want to the can that held the old style in place. Jon Thanks Jon, That's good to know!Tom Quote
JIPJOBXX Posted June 2, 2011 Report Posted June 2, 2011 I will rephrase that I used the old coil housing and placed the newer one inside the old coil. Works! Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 I will rephrase that I used the old coil housing and placed the newer one inside the old coil. Works! Ok, that's what the electrical tape on the coil is for. Gotcha!Tom Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 You guys know I just put in an NOS breaker kit a few weeks ago. I wonder if one of those "tiny wires" broke again? I'll find out in the morning. Tom Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 Last night I went to the car and tried to start it. No go. Soooo, this morning I took my tools to check it out and for spits and giggles I tried to start it. It cranked right up and ran beautiful all the way home. I've never had a coil go bad in any of my cars. Is it possible for it to fail then work, then fail then work? I'm stumped.:confused: I pulled the dizzy and the wires look fine. Tom Quote
Joe Flanagan Posted June 2, 2011 Report Posted June 2, 2011 I've had a coil do that in my daily driver, a 1987 Toyota pickup. It would be fine until it heated up. Then it would fail. Once I let it cool, it behaved normally. I tested it with an ohm meter right after it failed and the test confirmed that it was bad. BUT!! Just for fun, I tested it again about 24 hours later and it tested good. I swapped it out with a new one and that was the end of the trouble. Quote
dirty dan Posted June 2, 2011 Report Posted June 2, 2011 (edited) Last night I went to the car and tried to start it. No go. Soooo, this morning I took my tools to check it out and for spits and giggles I tried to start it. It cranked right up and ran beautiful all the way home. I've never had a coil go bad in any of my cars. Is it possible for it to fail then work, then fail then work? I'm stumped.:confused: I pulled the dizzy and the wires look fine.Tom Had that problem on a 71 LTD years ago. Took forever to find it. No spark with a warm engine, and when everything cooled down it would run fine. Here's a decent article on what happens... http://www.jackscars.net/coil_failure.html Edited June 2, 2011 by dirty dan Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 I wonder how old the my coil is. Who knows, it could be original. 70 years? Tom Quote
Jim Yergin Posted June 2, 2011 Report Posted June 2, 2011 Tom, I had that problem on my '41. When it got hot the coil would quit. Cool off and it would run. The last time it happened I broke down in town and was able to get a six volt coil at the local CarQuest but not one with the backside terminal. I ran the inside wire from the original rear coil post out throught the firewall and, like in the earlier post, mounted the new coil in the firewall hole. Jim Yergin Quote
Joe Flanagan Posted June 2, 2011 Report Posted June 2, 2011 I've read that in a pinch you can put an ice pack on the coil to return it to service. Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 Thanks Jim, I'll probably ending up doing that. BTW... did you get your woody out of 2nd gear? Tom Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 I've read that in a pinch you can put an ice pack on the coil to return it to service. Sounds like a '78 Fury police car I had once. I'd shut it off, then it wouldn't start. The Electronic Spark Control would get hot. I'd put a bag of ice on it, wait a minute and away I'd go. I finally bypassed the computer and put standard electronic ignition on it and it worked great.Tom Quote
Joe Flanagan Posted June 2, 2011 Report Posted June 2, 2011 You BYPASSED THE COMPUTER?!?!? That must be a high crime in today's world. Absolutely unheard of and most irreverent. You're my kind of guy. Quote
JIPJOBXX Posted June 2, 2011 Report Posted June 2, 2011 That ice idea i used also! Great for a test to see if the old coil is working or not. Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 You BYPASSED THE COMPUTER?!?!? That must be a high crime in today's world. Absolutely unheard of and most irreverent. You're my kind of guy. Ahhh...piece of cake. Cut 3 wires and drop in a dizzy with a vacuum advance and you're good to go. Them cars with the stoopid Electronic Spark Control's had no vacuum advance on the dizzy. The computer controlled that. I had that 440 police car back in the mid 80's.Tom Quote
P-12 Tommy Posted June 2, 2011 Author Report Posted June 2, 2011 Meanwhile back at the P-12 world....I bought an untested Solar Spark coil on E-bay for 15 bucks. If it doesn't work, oh well I'm out 15 bucks. I'll probably do the surgery on the my coil and put a later 6 volt coil in it's place. I didn't get a chance to do anything on the Plymouth 'cause I had to take my girlfriend to the Orlando airport for a flight to Boone, North Carolina to see her son and wife and 6 month old grandson Camden. On the way back the Navigator got a low right front tire and I had to stop and air it up. Ends up being a bad valve stem. Plus it had a bad coil in number 8 cylinder. Changed that when I got back. Was a very busy day. Phew! Tom Quote
P-12 Tommy Posted June 4, 2011 Author Report Posted June 4, 2011 I got my coil in the mail today. I installed it and the car started right up. I let it run 'till it was at operating temps. All of a sudden the car just shut off!! I'm like..what the heck! Yesterday I went and bought a 6 volt coil at Tractor Supply just in case. Needless to say... I did the surgery and got the new coil in. Ignition wire to neg. on coil and then pos. to the dizzy. Wouldn't start. I decided to do what Merle said and checked the points. I got it on the raised part of the cam and discovered the point were closed!! Huhh?? The points set wasn't loose at all. So I reset them and the car runs perfect again. How can points close themselves? The car ran, then not, and run again? I've never seen anything like it. Anyway.. Here's a pic of the new coil conversion. Tom Quote
greg g Posted June 4, 2011 Report Posted June 4, 2011 (edited) the screw can slip, or the rubbing block can wear enough especially if you don't put the lube on the wick, enough to allow them to close ever time. Which is why after 6500 miles, I need to recheck mine soon. Edited June 5, 2011 by greg g Quote
Merle Coggins Posted June 4, 2011 Report Posted June 4, 2011 Good to hear you solved the mistery. I had a similar issue a few years ago. I hadn't put any lube on my points rub block and it wore down fairly quickly. The points gap got so small that it eventually wouldn't run when hot. Luckily it was in my driveway when it got to it's worst. It had also been slowly loosing power. With the points gap that small the points aren't open long enough to fully discharge the coil's energy and you get a very week spark. It seems to get worse when things warm up. Once I corrected mine I was suprised at how much power my truck had again. Don't forget to reset the timing when you reset the points gap. The two go hand in hand. Merle Quote
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