Mule Man Willie

Sorry it's not a diesel question but I trust the advise here.
85 W-350 with 360 4-speed
Truck starts in the "start" position but as soon as you let go of the key it dies.
This just happened all of a sudden.
The switch is sloppy but is it the switch?
Thanks in advance.

j_martin

Look in the wiring diagram. There is probably an ignition resistor that is bypassed by the starting circuit. If the resistor is bad, you'll have those symptoms.

If everything else ignition (power windows, gauges, etc) fails, it's the switch. If the only thing that fails is the engine, it's the resistor.

hope it helps.

Mule Man Willie

Oops, had to edit this....
Everything works as it should when the key is "on" gauges, seat belt light and even the snow plow which only works with the key on.
So, maybe a ballast?
I'm gonna check it with my multi-meter tomorrow since it's raining today.
Thanks.

Mexstan

I second what j_m said. Before you start the engine and with the key in the ON position, check the voltage before and after the ballast resistor. Then after you try to start it and it dies, without touching the key, check both voltages again.

Let us know what you find and what fixed the problem.

Mule Man Willie

Thanks. Sure will

Mule Man Willie

Key on: 10.2 and 0.3
I'm guessing I found the problem. The 10.2 was surprising but I guess I ran the battery a little low yesterday fooling with it.

Mexstan

10.2 is quite low. Check the battery voltage directly on the battery posts (NOT on the terminals) to rule out any bad connections that could cause a low voltage reading. If the battery voltage on the posts is higher than 10.2, then you may have another problem somewhere else. However, with lots of cranking, then it is possible that your battery is low and that reading is correct.

NE frmhnd

Ballast resistor. Chrysler set them up to bypass the resistor for hotter spark at start-up.

Mule Man Willie

Yea, I didn't have a good ground for the multi-meter first time. It was 12.5 and still below 1

Got one today and fired it up.
Thanks all.
I wonder if I couldn't have just jumped the wires that go to the ballast to see if it would have fired up though. I can't imagine it would have fried the coil or points for a few seconds of running.

NE frmhnd

You could have put a jumper on it to see if it would fire. I used one for an 85 v8 fullsize when doing the 12 volt conversion on my farmall M. It backfired like crazy the day I ran it before I got the resistor in it.

Mule Man Willie

Funny that you said that because when I was taking the old one off the firewall I thought the same thing; "you dummy, why didn't you just jump it to test it"

j_martin

Actually, you may have been saved by your "ignorance". Farmhand's back firing was caused by secondary over voltage causing arcing and cross firing. A shorted ballast resistor is hard on things and sometimes causes permanent damage.

NE frmhnd

My conversion consisted of dropping a 12 volt battery in it to see if it would charge. It did. So I picked up a resistor next time I was in town.

No wonder it took a new battery every spring and a new voltage regulator every other spring. Went from pegging the 30 amp gauge at 6 volts to running about 10 amps at 12. I think someone labeled the rebuilt generator wrong.

My uncle was the one who actually ran it, I only ran it long enough to see if it would charge the battery.

But I'm also talking about something running around 6:1 compression, built to burn distillate or gasoline.