Help!!!! i have an electrical issue???

[Burn-N-Daylight]

Let me start off by saying i have been lurking around this site for a week or two before coming a full member. I recently moved to denver from washington state. So i decided to buy an 85 k5 with a 6in lift with 35x12.5 with a 350 nothing special. i recently bought an 83 thats been rolled i needed the motor since the crank had snapped in my 350. so i dropped in a 305 last weekend which ran great in the other rig but for some reason or another all of a sudden it will start up and it will sit at an idle for 10min and then it will shut off with out any warning. so i replaced the dist. coil i had voltage going to the coil and no power coming out. i pulled a plug wire off to see if i was getting spark and i had none. when i went to start it with a meter hooked up i had a voltage drop (9v) it does have new wires,plugs,cap,rotor, and new coil. it will just turn over and not start if i let it sit for a few hours it will start and then die shortly after. so i am at a loss is there any thing that i am over looking? any advice would be much appreciated. Thanks in advance

James

 

[Goose]

I think there was an electronic spark control computer of sorts in 1985. Maybe switching from a 350 to a 305 is doing something about adjusting you timing once it's warmed up. I know there is a way to bypass that junk, but not sure how. I know it's something to do with that wire connection at the distributor.

 

[Muddytazz]

Have you replace the ign module?

 

[Russell]

Dropping down to 8 - 9 volts while the engine is cranking is normal becuase the starter draws a huge amount of amperage, which temporarily reduces the potential energy in the battery. Its a bit like having a water hose under pressure. When you hold the end off, the water wants out of the hose really bad, and has a great deal of potential kinetic energy available, once you open the end of the hose up, tons of water moves out (amperage), and greatly reduces the pressure (voltage) until you plug the end of the hose back up again.

If you are only getting 9 volts to the distributor at all times, check to see what the truck's elecrical system is running at by checking the voltage off the firewall distribution block. If it is different than the voltage at the distributor, then you want to start tracing the wire back through the fuse block connector, up to the ignition switch etc, and figure out where you are loosing voltage.

You may want to consider replacing both the pickup coil and the ignition module inside of the distributor as well. Either could cause the problems you are experiencing.

 

[Burn-N-Daylight]

thanks for the info i just replaced the ignition moduloe with an new accel highout put and still nothing so im gonna go and replace the distributor and with a little luck it will fix the problem, never had to replace one before so i hope all goes well