This truck is gettin' me down. I know I'm missing something simple. I'm getting no fire from the coil to the distributor and I have 12V to the coil with the switch off or on. Anybody know this one?
2007-02-01 00:57:58 · 8 answers · asked by Ricky J. 6 in Cars & Transportation ➔ Car Makes ➔ Chevrolet
I own a shop, and a "74" chevy pick up truck. I bought the truck new, and have had it in my possesion since. It too came with a points type distributor, but I changed that over to an HEI years ago. Some 74's came with an HEI, but they were mostly points type. As far as I know, the HEI didn't come in the 350 until late 74 or early 75. Changing it over was the best thing I ever did to it, but one must remember to run a new wire for the power from the ignition switch. Right off hand there is one thing here that is not right. The power to the coil should be around 6 volts, due to the wire that goes from the ignition switch to the coil should be a resistor wire that heats up, thus cutting the fire to the coil down. If you feed 12 volts to the coil it could damage it. The wire that goes to the distributor from the switch is shorted out, probably a bad ignition switch, or someone has replaced it with the wrong kind of wire. This wire is critical to have the correct voltage to it. Check to make sure the points are clean. Set the gap with a gage to .017-.019 and then turn the engine until it closes the points. Now, use a dollar bill to pull between the points to clean them with. Do this several times to insure they are clean. Trace the wire back from the coil to the ignition switch, and find the sorce of the constant voltage. It is either touching another voltage source, or the switch is shorted out. If it has the wrong wire in it, (it should be an aluminum wire) and you can't get the right one for it, you can buy a ballist resistor that will cut it down. The older mopars used this resistor, so you should be able to find one easily. You only need to use one that has two terminals. Mount it to the firewall, and splice it into the wire that goes to the switch and the + on the coil. Use a meter to check the wire that goes from the - side of the coil to the points. It should have power when the points break when you turn the engine over to start it. Keep diging, you will find the problem.
Glad to help out, Good Luck!!!
2007-02-01 03:55:19 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Hi rjohnson4. Something does not line up here. A 1973 should have HEI ignition. The coil should be integral within the distributor cap. Reading your question I get the impression the coil is seperate from the distributor. You should not be getting power to the coil with the ignition swith in the off position regardless of which type it is. First you have to get the power supply problem straightened out. Power to coil with switch in the run or start position only. Depending on how long the coil has been getting a continuous 12 volts it is most likely toast along with the points and condenser. A little more exact information as to what you have would sure help in order to answer your question.
2007-02-01 02:35:28 · answer #2 · answered by parkmistyred 4 · 0⤊ 2⤋
The negative wire on the coil goes to the points and condenser.The positive side of the coil is powered from the ignition switch.In reguards to the fire from the coil.The coil could be corroded where the distributor to coil wire plugs in the coil.Try to scrape corrosion off inside of port.Check the distributor cap for graphite stem that makes contact with rotor bug.Is it broken?Check points.Are they gapped correctly?Make sure points wire are not grounding on distributor body.Good Luck.
2007-02-01 04:06:48 · answer #3 · answered by (A) 7 · 1⤊ 1⤋
O.k. first of all a 73 should have an HEI {High Energy Ignition} Two things could have happened.You fried either the coil or the points in the coil. A round coil has points and if the switch is getting 12v all the time even off you could have fried it.
2007-02-01 01:20:34 · answer #4 · answered by Sidetracked0260 4 · 0⤊ 3⤋
GM didn't start with the HEI system until 1975. take that to the bank. your problem starts with the 12vdc to your coil. it must be switchable 0 volts with ignition off. after you correct that problem install a new set of points and condenser. set dwell 29-31.
2007-02-02 01:05:45 · answer #5 · answered by DASH 5 · 2⤊ 0⤋
If this is a points style distributor, which it may be for the year, try replacing the condenser. On some GM models, the condenser may be part of the points assembly. If so, replace the point / condenser assembly.
2007-02-01 01:14:25 · answer #6 · answered by Mad Jack 7 · 0⤊ 1⤋
don't listen to the crap about hei distributors. yours originally had pts and condensor, those are the guys to point you in the right direction. I will say that you can drop an hei distributor in and have less of a headache though.
2007-02-01 04:28:09 · answer #7 · answered by buddy leight 3 · 2⤊ 1⤋
Sounds like main P.C.M. computer problems! I had a simular thing happen to my chev. the computer doesnt cost too much if your truck has a v-8 305 or 350 the computer cost only $115.00 at Auto Zone or Checker auto parts. I have several extra P.C.M. computers in good working condition so if you cant find one where you live contact me and Ill send ya one for free.
2007-02-01 01:06:44 · answer #8 · answered by Lots of money but no sense 2 · 0⤊ 5⤋