Ideally you want to stop it from actually starting when testing voltage during cranking, so you can give the starter motor a good turning over.....pull the main HT lead off the coil and test again. Try 2 or 3 times to make sure it does not vary.
if indeed 11.43V, that is good voltage and close to the 11.5 I'd have expected on the S4
(L-Jet is 10,5V as Eric rightly says)
Ok, so I tried a couple of times, each time with slightly worse results than the time before. It drops to 10.5 for a second, then is at around 11.6, dropping to 11.5 and eventually 11.4 (that process takes around 8 seconds, I stopped at that point as readings seemed healthy)
I'd also remove the earth cable from the battery that is screwed to the floor of the boot, sand it, add a little copper grease and bolt it back. Also clean both battery posts (Batterie Pole)....just to eliminate that from any equation.
The main ECU ground you are looking for is this here (remove both bolts, sand or wire brush clean and add some copper grease, bolt back on):
Cleaned main ECU ground, battery posts and battery earth cable. No effect on starting the car.
Does the Throttle position switch (TPS) 'click' as soon as you try to move the throttle with your finger?
Yes, it does.
next time you have the fuel stench, pull out the sparkplugs and check them for wetness, or lack thereof.
I did not experience fuel smell today, but I pulled the plugs nonetheless. Here are some pictures. I also attached a couple of other pictures, perhaps something stands out.
Looks like that wire has a worn bend. Is that to be fixed?
What is this thing doing and should I be replacing it due to the rust on it?
Maybe remove and clean out the bosch Idle air valve (IAV) on the plenum (use brake cleaner, allow to dry out for a few seconds, then a quick squirt of WD40 for lubrication purposes)..check the rubber grommet/seal for the IAV in the plenum is sealing, use some silicone grease to seal it.
Is the throttle linkage perhaps binding? (ie. pulling the throttle ever so slightly open) test with your finger that you have the tiniest bit of play in the linkage ball at the plenum end (you are testing that the throttle is not being pulled off the throttle stop by the linkage)
false air (dt. Falschluft) can plague these cars, make sure all hoses in that department are airtight.........with the car idling, spray starter spray around all air hoses and listen...
Those would be the next steps I presume, but the car was too hot and I need to do some serious reading first
Thanks a lot for the help up until now, even though I did not fix the problem yet, I sure like to learn more about the car in general. Tomorrow, the Spider is going to a pro for adjusting the valve clearance, but I would like to do the rest myself, with your help