I have 1991 Cadillac DeVille and sometimes when I turn the ignition to start it does nothing. All the dash lights go on, but the starter does not engage. It is sporatic, sometimes it cranks sometimes it does nothing.

Do you see a light that says SECURITY on the dash somewhere? This can turn off your starter and disable your car. Read about it on this link with options on how to fix it yourself.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 Cadillac Deville with anti theft security problems VATS system

do you mean 'abs'?

OK, I have this intermittent problem on my 1997 Cadillac Deville. Sometimes, when the engine is hot and sometimes when cold, the starter will click, (solenoid), but the starter will not turn over the engine at all. I have to toggle the ignition switch to the start position and to the ignition position several times to make it work. But, this only occurs intermittently for me, and I have never really gotten stuck more then a few minutes.

The solution, of course, is to replace the starter to get rid of the intermittent problem.

Is the speedometer showing '0' or is it just not displaying any numbers at all?

Good luck on this repair.

So you have no crank no start correct. Three possible items to check : ignition switch,neutral safety switch, starter relay. and if applicable starter interrupt relay.

Replace that relay for that is at fault

The ignition switch attached to the column is probally bad, check the small wire to the sloenoid for battery when the key is turned to the start postion, if no battery, your not getting power from the ignition switch to the starter solenoid.

You need to check and see if you have power to the starter,the purple wire while someone is turning the key to run.Should have at least 9 volts to the solenoid.Sometimes if you tap the starter with a hammer while turning key to run and it turns over it is the starter.

I would suspect the ignition switch is failing and needs replacing.

it isnt making a good conection on the body ground

get new key with newer chip or replace ignition cylinder.