Pontiac Repair: 1997 Chev 3500 series Cube Van - Will NOT Shut off/down., negative battery cable, cube van

Question

Hi Todd:

May I ask why is my 1997 Chev 3500 series Cube Van (176,000 clicks approx.),(gas engine),(350 5.7L) - occasionally start and having an odd scraping or catching sound and when you turn key off (even with key pulled right out), it is still running?

On one occasion prior to this, it did not start at all, yet you could hear the fuel sending unit, and the dash was lit.  Chucked it up to be starter.

A few days later it started and shut off fine.

However, a couple days after that, it started with that scraping or catching noise and could not shut him down - that is to say not right away.  I panicked and attempted to restart it and then it shut off...what a relief.

Subsequent to this, this mystery problem had left me stranded on side of the road and had to get towed. I should have known better, but it started fine without the sound and checked if it could shut down (it did), so I ventured off to the gas station.  I was able to shut it off and gassed up.  Upon starting, that noise and inability to shut down happened again.  So, I drove it home anyway but after approx. 2.5 minutes of driving, the truck shut down completely.  This killed the battery.

Replaced the starter with a rebuild starter, however, same thing - could start it, made that weird noise, and could not shut it down, so we had to disconnect the negative battery cable.  Next, we examined and handled some wires underneath steering column, and out of the blue, it started normal, without the sound, and it shut off normal.  We could start and shut off several times in a row like nothing ever happened.

Of course, I know this does not mean it has corrected itself.  Do you think it could be the auto-shutdown relay, or ignition switch, or something else?

Please let me know what you think.  

Thank you, kindly,

Vera


Answer
Hi Vera:

well it has to be some kind of a power feed issue. Does this have any kind of a aftermarket remote starter or aalram system on it? If so that is the FIRST place to start looking! If not then an ignition switch would be my best guess that maybe the contact in the switch are stucking on even know you have the key off. For some reason the fues box is remaining powered up after the key is turned off.