Woody Branham Posted March 19, 2007 Report Posted March 19, 2007 I still cant get my 1950 DeSoto to start. I yanked the distributor and found a short in the wire running out of the side to the coil. Fixed that. Retested everything and all tested good on my meter. Everything in there has less than 200 miles on it. Put it back in the car and again... No Spark. I pulled the cap, turned the key on and opened the points and saw spark but still nothing going to the plugs. With the key on only the Bat side of the coil shows power. What am I doing wrong?? Woody Quote
greg g Posted March 19, 2007 Report Posted March 19, 2007 If you have spark at the points, it gotta be downstream. Assure all you plug coil wires are fully seated i the cap. Make sure your rotor is fully seated on the shaft, makd sure the center carbon piece is indeed i the cap. Makes usre your wires are nice and tight on the coils. Also recheck your firing order. I had a similar experience when I tried to fire up my newly rebuilt engine, everything was correct but the spark plug wires were ont ower off on the dizzy cap. If everything is correct, stick a phillips heaf screwdriver into the number 1 spark plug wire, and set it up so the shank of the screw driver is gapped from a head bolt and crank the engine sot see it the spark is getting to the plugs. Quote
Plymouthy Adams Posted March 20, 2007 Report Posted March 20, 2007 If you have voltage to the points and they spark when you short the contacts..then for some reason the field in the coil is not collasping and generating the secondary high voltage..do you have a spare coil to test with..even a 12 volt coil will do if is is of the external resistor type..use it without a resistor for 6 volt application..will work all day long... Quote
Merle Coggins Posted March 20, 2007 Report Posted March 20, 2007 You will only measure voltage on the key side of the coil if the points are closed. They are then providing the ground for the coil and you can't read voltage on the ground side. If the points are open you should see voltage on both coil terminals because the circuit isn't complete without the ground through the points. If you can't measure voltage at the points side of the coil with the points open, either the wire is shorted to ground, or the coil is bad. Merle Quote
Normspeed Posted March 20, 2007 Report Posted March 20, 2007 Woody, if you replaced the distributor cap or rotor, make really sure you have the correct parts. There are caps and rotors that will fit the distributor but will not make internal contact due to either cap too tall, rotor too short, or rotor arm too short. Compare them with your old parts for an exact match. Other folks have run into this, and it nearly drove them batty. Quote
Tim Frank Posted March 20, 2007 Report Posted March 20, 2007 A Q&D test would be to put your voltmeter across the two coil terminals and crank the engine over. The reading should try to cycle from 0-12 V. If you don't get a reasonably smooth oscillation, you have a problem on the primary side. If you get the oscillation, you can move to the secondary side. Without knowing the history, did it stop running suddenly, or have you done some work and now it won't go? Quote
bob westphal Posted March 20, 2007 Report Posted March 20, 2007 If you have fluid drive you may have a short in the interuptor switch circuit. This switch actually shuts the ignition off momentarily in between up and down shifts when you release the throttle. Quote
Woody Branham Posted March 21, 2007 Author Report Posted March 21, 2007 Checked the coil on both sides as suggested. With points open I get a reading on my volt meter of 6+ volts . When I crank Tthe engine it turns a few tumes then acts like the battery is going down. I tried cranking the engine with one test lead on the Dist side of the distributor and grounding the other. The needle bounced back and forth between 2 and 4 volts then again acted like the battery was going down. This is frustrating and taking time away, what little I have, from working on the p11. Any other Ideas? Quote
1just4don Posted March 21, 2007 Report Posted March 21, 2007 Have you tried to hold on to the spark plug end of the wire and cranked it to see if 'any' spark comes thru??. It is also common for coil wires to be bad,,have you checked that?? Or changed with one thats known to be good. Once upon a time I changed condensors in a dizzy,cause the condensor was bad, (car wouldnt run)inadvertantly the side of then NEW condensor touched the side of the dist. shorting it out and it would not fire. I am sure you are probaly smarter than I was, still question remains, is the condensor GOOD and is it touching the dist anywhere.?? Good luck, put a charger on the battery and it should crank for a longer period,plus recharge relatively quickly. If not, might be time for new battery anyway!! Sometimes a old car will fire better when a push or pull start helps them turn quicker. Not a cure all but a quick fix for a temporary problem!! Quote
Norm's Coupe Posted March 21, 2007 Report Posted March 21, 2007 As Don mentioned, you could just have a bad battery, even if it's fairly new. If the battery has set for awhile (several months), or not charged every 30 days, the cells could be crusted. The battery will charge up then, but it won't hold a charge when you try to use it. It may even test good and not hold up well enough to start the car. I had one like that. Took the battery into the shop and they said it was good. Told them I wanted to buy a new one anyway. Put the new one in and the car starts right up. You should be able to do a lot of cranking on a good battery. Quote
Woody Branham Posted March 22, 2007 Author Report Posted March 22, 2007 Recharged the battery and tested it with my meter. Key on 6.8 Volts.... Cranking 6.2 Volts. Pulled the coil wire and put the end near the block while helper turned the engine. No Spark from the Coil. Quote
1just4don Posted March 22, 2007 Report Posted March 22, 2007 lots better car experts out there than me. Would a bad condensor not let the coil put out thru the big termional?? If a new condensor doesnt fix it,,,I would 'try' a new coil!! Quote
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