No Crank Situation.

[markizme]

Hello gang, I will try to make this short. Today I started the 68 GMC and the wire to the kick down switch smoked itself. The acc hot wire had a bit of cracked insulation and grounded itself and smoked all the way to the fuse block. I shut the truck off, investigated the damage and then tried to start the truck. The engine wouldn't crank. So I started testing circuts. From the firewall half of the fuse block it is all ok. I ran a hot wire to the starting circut, big fat purple wire, and the starter spins and with the key on, will start. I'm getting juice into the ign switch, and getting juice thru the fat purple wire from the ign switch. I haven't cut into the under dash harness yet, I lost all of my patience by then. It acts like a neutral safety switch is bad or mis adjusted when you try to turn the key. All else seems to be working as it should. What am I missing? Again, thank you in advance for your help. Respectfully, Mark

[HO455]

Having had my ignition switch go bad recently I know that the ACC post on the switch and the SOL post are next to each other and the ACC being shorted may have melted the switch and the SOL post is no longer able to conduct electricity properly. Look at the last posting in my WMB thread below for more info and some pictures of how my switch was damaged. Try measuring the voltage at the neutral safety switch with it plugged in then unplug it it from the switch and measure it again. (While in the start position) It may help you trouble shoot the problem.
Good luck.

[markizme]

Originally Posted by HO455

Having had my ignition switch go bad recently I know that the ACC post on the switch and the SOL post are next to each other and the ACC being shorted may have melted the switch and the SOL post is no longer able to conduct electricity properly. Look at the last posting in my WMB thread below for more info and some pictures of how my switch was damaged. Try measuring the voltage at the neutral safety switch with it plugged in then unplug it it from the switch and measure it again. (While in the start position) It may help you trouble shoot the problem.
Good luck.

Before I go look, I went out to test to see if I was getting juice thru the neutral safety switch. After hooking up the test light, I turned the key and the truck started. Now, I have to figure out what caused this so it won't happen again. Off to read your post, thank you for chiming in, mm

[markizme]

Originally Posted by markizme

Before I go look, I went out to test to see if I was getting juice thru the neutral safety switch. After hooking up the test light, I turned the key and the truck started. Now, I have to figure out what caused this so it won't happen again. Off to read your post, thank you for chiming in, mm

So I spent some time with the truck yesterday, and among other things addressed my no crank issue. Pulled the ignition switch and no where on it did it appear to have gotten hot. I then tested, then jiggled the NSS and the truck started. My fuel guage was lazy at best, and thanks to the knowledge of our members, tested my guage and then pulled the sender which was starting to deteriorate. The sock was dissolved away, the whole unit was corroded and the brass float was rotten. Those things are on order. Going to attempt the heater core today. Thank you all for your help!
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[ncpetersc]

If the sending unit was corroded, how was the tank? A new sock might get you by, but might want to think about replacing or cleaning the tank if it is corroded as well.

[markizme]

Originally Posted by ncpetersc

If the sending unit was corroded, how was the tank? A new sock might get you by, but might want to think about replacing or cleaning the tank if it is corroded as well.

I shined a flashlight into the tank through the filler neck, and it appears that the corrosion is loose and very light. It has accumulated on about the top 6-10 inches of the tank, and at the bottom which I believe is from the crud washing off the sides of the tank. The interior of the tank is shiny otherwise. I'm debating on a 5 pound bag of gravel and some water in it anyhow since the truck has a new motor, and I have a brand new carb ready for installation. The sender is on order, and will not be here until the end of the week.

[markizme]

Rut Row! I've hijacked my own thread.