2004 Porsche 911 C4S Hot Weather start problem

My car has developed a hot weather starting issue. It is fine in the morning, but after sitting all day in the desert at work, it doesn't want to fire up. Anyone have any ideas, besides not letting it sit in the desert? You Tube ***UPDATE.*** So I found a thread on Pelican parts forums, where someone had the same issue. http://forums.pelicanparts.com/porsche-996-997-991-forum/747417-1999-996-wont-start-when-hot-cranks.html They swapped out their Crank Position Sensor and the problem went away. I figured since it is a cheap enough part, I might as well swap it out for a new one and see what happens. Well, I think it has worked. I haven't had the issue at all since changing that out.

Engine is overfilled with oil. Best get that level down. Engine start problem is hard to say. About all I could do would be to offer guesses. The engine kind of cranks poorly which suggests a low battery (though the volt meter doesn't really back this up). A problem with the battery cables could also account for the behavior. There is also the possibility of a fuel delivery problem. I note the engine doesn't spit or sputter though and once it fires appears to run without any real signs of a fueling problem. Long shot but have you done an E-Gas calibration? Steps are in the manual but for my 2002 Boxster and 2003 996 Turbo with the key off and one's foot off the gas pedal through the entire procedure turn the key on and leave on 60 seconds. After at least 60 seconds turn the key for at least 10 seconds. Next time the engine is started the calibration is done.

The battery and starter are strong. CPS working. Oil pressure sender failed (should point to 0 with key ON engine OFF). Perhaps try e-gas calibration first. Put the key in the last position before crank and leave it there for 60s then turn key OFF and wait for 10s. Next thing to check is error codes and fuel pressure.

Do the gauge readings allow you to rule out starter cable heat soak?

Thanks for the info. This is how it starts up in the morning. You Tube

Quotes source post: 14276055

From the gauge and the cranking sound. Looks and sounds very healthy (and even compression) to me.

While I know you are wanting to resolve the hot start issue, that the oil level is above max with the engine cold indicates the engine is really overfilled with oil. You need to get to the point you know the engine has the right amount of oil in it and confirm electronic oil level sensor is operating properly. I won't go so far as to say the high oil level is the cause of the hot start problem but that high oil level bothers me more than the hot start problem. The hot start problem doesn't pose a risk to the engine like an overfilled engine does.

The BAR is just over 3 on hot start but I guess it's because it was 118� outside.

Quotes source post: 14276156

Gotcha - I had similar symptoms & did the starter+y-cable refresh. So far, so good. But it's a little early to say conclusively if my updates did the trick.

Mine does something similar. Doesn't require quite that much cranking, but more than I would consider normal. It does seem to happen when hot out - and sometimes the engine stalls immediately after starting but then restarts pretty easy. It hasn't become consistent enough to prompt me to do more than some cursory research though.

Might. and I stress MIGHT, be an issue with the ignition coils (not truly coils as there is one for each cylinder). They are relatively heat sensitive and degrade rather quickly in high heat. And yes, your oil level is too high.

I had the oil changed and had my guy check for error codes. Nothing came up regarding this issue. He was unsure what it could be, and suggested it may be vapour lock. With the oil levels good, it did the same thing in the heat today. (111 degrees F) Has anyone else experienced this? If this is vapour lock, any ideas on preventing it happening? Thanks.

Can't say for sure as not enough experience with it since I only drive the 996 a couple times a week, but in Vegas we have been in the triple digits for a month now and the car does seem to take a bit more crank to get it going. No issues after but a couple times it had me wondering if something was wrong.

Maybe purge valve hanging open/leaking allowing fuel vapor to be pulled into the throttle body? Similar to the hot start problem at the fuel pump when this happens? If that is the case then cracking the throttle on hot start might help. With the high ambient temps you guys are having it might just be heat soak "vapor lock" like your mechanic suggested.

I had the exact same issue on my audi S4 it turned out to be a coolant temp sensor failure which was like a 10 buck part and a 10 min job. i assume you can read the temp in durametric so it maybe worth a look, on my audi i didnt get any codes about it failing. I would be able to cold start but if i stopped after a long drive for gas or something it would barely start, or like you if it was sitting in the sun when it was hot. It got worse over time where it was harder and harder to start until one day it wouldnt start at all and i had to take it to a audi apecialist shop and they had seen it before so it was a simple fix.

Updated first post. I replaced the Crankshaft position sensor and the problem seems to have gone away.

Quotes source post: 14426272

how long did it take? mine has had some odd hot start problems so im thinking ofcswapping mine

No time at all. It is one bolt and a clip. My mechanic did it for free when he was doing my wheel bearing.

crank position sensor and fuel pressure sensor improved my slow start issue to where it's almost non-existent. Y-cable & starter replacement took it from bad to okay, then CPS/FPS improved it further. I think a cable somewhere may need replacing, likely the one upstream from the y-cable.