How about make and model to start....
hers: do you hear cylinder firing or is it just turning over ?
his: you mean you turn ignition to start and nothing ? like dead battery ? lights work as bright as always ?
Just start drinking. Try again in the morning. Tell your wife to start walking to work now. She’ll get there in time.
Budget? I’d recommend going through Craigslist or cars.com (private listings) and having a mechanic on standby.
Car 1: Out of gas
Car 2: Wrong key
I had a 94 blazer that would turn over but not start. I shot some ether into the intake and it ran for a while and quit. It was a fuel pump in the tank. If the key will not run in the ignition it sounds like the switch is shot. The tumblers in the switch could have come loose. Know knowing what you have makes diagnosis just guesses.
On the key deal, my brother has a Plymouth that has started doing this. I haven’t researched the replacement of the integrated lock mechanism but I’m betting it won’t be cheap. For now he inserts the key and gently taps on it while rotating the key. It seems to giggle the tumblers into cooperating.
Did her car just quit while it was running?
Well, sounds like the fuel pump on her car.. maybe a lot of other things.. and, as for the ignition that won’t turn, I had that happen to an old chevy PU I owned. I stuck a big screw driver in the key hole and latched a pair of vise grips on it.. and I turned it. It worked after that.. didn’t need a key, but no one knew that...
If none of these are the problem you have an electrical problem and are screwed.
In all seriousness, I don't even know if cars have these same components anymore.
On the key problem. Try moving the steering wheel side to side while working the key. Sometimes the steering wheel locking pall will cause the ingnition lock to hang. Try using your spare key it might be in better shape than the one you have been using. Put some light lube on the key and work it around in the lock.
Ethanol content I’d wager . . .
You may have to turn hard on the steering wheel to get the tension off of it to get the key to turn.
Make sure your car is in park all the way.
Here’s where I do mah searchin’...
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1193444-steering-wheel-locked-key-wont-turn.html
I use google like this:
1984 300d ignition won’t turn site:www.benzworld.org/
Do you hear a click or clicking?
For yours, there might be nothing more than a strain on the ignition lock. Try slightly turning the steering wheel in one direction while trying to start it. If that doesn’t work, try turning it in the other and repeat.
If you both bought gas at the same station recently, check for water in the fuel.
Yours, with the key thing....this can be a lot of things. I have found that ignition interlock keys or chipped ignition interlock keys can begin to operate a little intermittently as they age. Maybe the teeth on the key wear down; sometimes it is a matter of the steering wheel being left in a too-extreme position...imagine turning really hard to get into a parking place and turning off the engine right when the wheel is all the way at one end of its rotation. Try not to do that. Get into your spot, then un-turn the wheel back in the direction of the center. If the key is worn, maybe it’s just not activating the tumblers enough. If that is the case, you may need to get a new key made. Cheap, if it is just a vanilla key, and I would try that first for $1-2-3. More expensive if it is a chipped key. Some auto parts dealers can make chipped keys for $40 or so...dealers usually want hundreds of $$.
Not to leave any stone unturned for you, have you tried inserting the key the other way up? On my old Ford, the key is a mirror image on each side. Over time one side wore down just enough on one side to not properly engage the pins. Inserted the other way, it worked just fine. If you have another key, try that as well. Sometimes the simplest things will work. Otherwise, I dunno.
The independent M-B shop where we have maintenance (very seldom) done, diagnosed the trouble as "crankshaft position sensor". Now I suspect that is basically similar to what we oldtimers used to call "distributor rotor". Anyway, it's a solid state device which I am told does eventually become sensitive to heat and consequently fails. Easily accessible and not too expensive to replace. Just another wonderful "advancement" in automotive science.