Car won't start, what could it be?

[venturawildes]

2002 996 Cab. Went on a trip and left my car at the airport, was gone 7 days, when I got back it wouldn't start. Everything worked, lights, radio, window etc. Initially I thought it was the battery, but for some reason after monkeying around with the key, it started. Well I went to drive it today and no dice. Everything appears fine, it isn't the battery, turn the key and nothing happens. Could it be the switch? I hate to just swap out parts without really knowing what it is.

[solent]

I had similar issue after stereo was installed and drove home. Would not start next day. Battery was good. Turned key, engine did not crank. Mine tuned out to be DME fuse (I forget the fuse number in the fuse box, but I think the installer had pulled it out and reseated it while he was trying to find the bose amp fuse. I guess it was not making 100% good contact - so started at the shop, but not at home. (you can google the fuse box diagram if you do not have original to see which one is DME). Once I removed and reseated the fuse - everything worked - and haven't had a problem since. That would be an easy answer. ALso, try the spare could - could be bad transponder in the key. Next issue might be ignition switch itself (cheap and easy to replace) - which apparently is common failure - then could be loose or bad ground somewhere else in the car (there is a major ground strap under the engine - check for corrosion or loose connection) - next to check would be starter itself (I didn't have to go that far, but you could probably take a multimeter to the starter to see if you are getting any voltage there when you turn the key) - finally could be DME itself (or various related sensors) - if you do a search on DME here or in similar forums you'll find a bunch of info on that ... good luck

[soverystout]

It could be the clutch switch going/gone bad. Is your car manual? If so, push the clutch in to where you normally would for start up. If nothing happens, push the clutch in as far as it will go and then see if it starts. If it starts fully depressed, the clutch switch is going bad.

[fpb111]

How long was it alone this time? Maybe it is getting in a snit because you don't drive it enough.

Seriously, The car goes to sleep after X days and will not respond to the transponder. There is a procedure to wake it up. Something like using key unlock and relock the door then unlock with the remote. Or unlock the door with the key and start within 5-10 seconds. Look in your manual.

[venturawildes]

I checked out the fuses and they were fine. I found what appears to be an add-on, bunch of wires with semi-ghetto connections. Took the tape off and it looks like 2 additional relays wired in for some reason. The ground had come loose and when I put it back the car started fine. Hmmm, now to figure out what the add-on is, and why it would keep the car from starting.

[venturawildes]

How long was it alone this time? Maybe it is getting in a snit because you don't drive it enough.

Seriously, The car goes to sleep after X days and will not respond to the transponder. There is a procedure to wake it up. Something like using key unlock and relock the door then unlock with the remote. Or unlock the door with the key and start within 5-10 seconds. Look in your manual.

I tried that, and agree that my little Fraulein gets upset without proper attention.