supersmitty

I recently just bout a M38A1 jeep and it turns over and supplys power into the distributor but i puts no spark out. the solenoid is good what could it be??

mack1

Hi Smitty and welcome to TSF,

Old cars and jeeps....I know and like them. You have voltage to the coil if I understood your post. The other coil wire goes from the coil to the points in the distributor where it ends up at the points. Pop the cap off and check the points contact surfaces and make sure they aren't burned. If metal has ganged up on one contact and a hole in the other, the condensor is bad. With the ignition on, if you have no voltage to the points, the coil is burned out. Even without a meter, you can check for voltage at the points by using a screwdriver point, short across the points if they are open or if closed, pry the points open/shut. Look for arcing at the points or screwdriver tip.

If you get point arcing, see if the coil is putting out high voltage.
Pull the HV wire out of the distributor cap and hold it near the block using insolated pliars. Use the screwdriver on the points again except this time watch the high voltage wire for spark. The spark should jump 1/4 inch easily. If not, the HV wire could be bad, so repeat the test, except this time, use a copper wire connected between a screwdriver blade and the block. Pull the wire out of the top of the coil and hold the grounded screwdriver tip just above the coil's HV output. Do the screwdriver shorting at the points again. If you get the 1/4 inch spark jump, the coil is OK and the HV wires are bad. Install a new set of plug wires.

It is likely that you just a new set of points and condinsor. You might need plug wires. You might need new plugs. You might need a new coil. At the end of it all, you should get spark across the plug gaps. I usually test number one plug by either pulling the plug or using a spare, lay it on the block with the plug wire attached and turn over the engine. I look for a good blue spark across the plug gap.

Also make sure that the gap is set right on the points. Normally about 16 thousands if my memory serves. Better look that up in the book....been a while since I set point gap.

Very best regards,
Mack1

supersmitty

Ok thank you, but we checked the coil and it works. The points are making full contact and have no pitting or anything wrong with them. Is there a way to test the condensor if u take it off??

mack1

No good way. A condensor is actually a capacitor which is rated in microfarads. They don't list the capacity of condensors so no way to compare with a capacitor of the same value. I haven't bought one in years, but they used to be relatively cheap. Probably just need to get a new one.

If you have a multimeter, you can check the resistance of the plug wires. They should be less than 30,000 ohms...usually about 8,000. You could also use it to see if the capacitor might be good. Measure the resistance between the lead and the case of the capacitor. It should read zero ohms at first and slowly increase. On the resistance scale, the meter supplys current to the capacitor causing it to build up charge inside. Short the lead to the case to discharge it before you start. If it does this, it indicates that the condensor might be good.
Note again what I said in the first post. If there is no buildup of metal on either contact surface of the points, the condensor is most likely OK. When the points open, the magnetic field collapses causing very high voltage on the secondary winding and high voltage on the primary windings where the points are connected. The condensor absorbs that energy keeping the voltage low enough to prevent arcing across the points. If you get sparking across the points, you get a cavity on one point and metal buildup on the other indicating a bad condensor.

There's usually a braided strap from the plate where the points are mounted to the metal case of the distributor. Make sure that wire is connected. That's the ground path for the current through the points. Also, make sure the ground cable from the battery to the engine is good.

If you can measure the ohm values of the coil, it might tell you something. The resistance between the input terminal and the output terminal to the points should be quite low (less than 100 ohms if memory serves). Measure the ohms from the high voltage terminal (top of the coil) to either of the other two and the ohm value should be several hundred ohms. It this reading is very high (megohms), then the output coil is broken inside.

Wishing you luck,
Mack1

supersmitty

Thank you for all the help. I changed my condensor and that was the problem.

mack1

You're very welcome.

Have a nice day,
Mack1