1985 wont crank

[Bluex99]

My 85 wont crank at times. Lots of battery. Any ideas why

 

[Rruuff Day]

Could be a number of things... poor ground, solenoid, starter brushes wore out. While someone tries to crank it, try tapping the starter with a hammer.... my old chevy back in the day experience...

 

[LE BARON]

Could be a number of things... poor ground, solenoid, starter brushes wore out. While someone tries to crank it, try tapping the starter with a hammer.... my old chevy back in the day experience...

A wise mechanic always had a hammer handy for electrical starter faults.
If it is fairly consistent then whip out the multimeter and have someone hold the switch in start and check current to the starter solenoid. If you have power then it is either the solenoid or the starter. If no power then trace back to the relay. Usually, but not always, a starter is fairly well grounded.

 

[Bluex99]

This issue does not happen all the time. Its only happened 3 times. Its a auto trans car. Neutral safety switch?

 

[Dave91TM]

As always look for something simple. I went through a slew of intermittent no start conditions including tows. The problem
I believe was the VATS system. If you try to start it ,but Vats detects an error, you'll get power but no starter and no fuel pump.
Could be a misread of your key resistor, could be the transmission switch. All you can do is organize a check list and go through it one at a time. There is a ton of info on the internet. I got so fed up with mine that the final cure was to install a VATS by pass from New Rockies. Wasn't cheap and it bypasses the entire security system, but ...it starts.

 

[Bluex99]

I dont think mine has a vats system.

 

[Dave91TM]

It appears that the VATS was not in them until 1988, so that one big issue you do not have to worry about, sorry if I steered you wrong,
As I noted you need a check list and go through it. Good Luck