Guys, urgent brain storming needed. Did spring service to my car (plugs, leads, clean in air intake, air, fuel filters, engine oil, brake fluid…) , engine was running fine, did a small trip around my house to check everything, ca 5km. Then i visited car wash, did common self WAP washing (of course NOT under bonnet) after ca 500m of driving, engine stalls. Was lucky that i stopped on the gas station. But engine didnt run. From time to time, it coughed a bit, but nothing more. After that, white smoke blew from air intake. Did several attempts, left car for a 30min. or so, than engine miraculosly started and runned smooth for ca 2 min, but after that stalled again (didnt drive it) . And again engine cant run, occasionaly white smoke blew from air intake…(can smell a gas in that smoke) I deeply suspect the car wash and therefore water in the gas that Went somehow through the filler or so (until car washing, car was running fine)… Any other idea? Could be the water in the gas the reason or am I missing anything important?
The first suspect is always a bad distributor cap or rotor. Replace both of these before you go any further .
Marek - is your drain that keeps water from accumulating and covering your gas cap clear, or is it plugged?
If plugged it can be cleared with a length of string trimmer line.
I thought it is clear, but obviously its not. Problem solved, it was water in the gas tank. I wouldnt believe that a commom wap washing could result in this… i poured a gasoline water remover to the tank, and engine started to run after a while… So Jag is back in the garage before midninght 
I leave this topic here, maybe it can help someone in the future. Thank you guys for trying to help me, appreciate a lot…
Marek …
Glad that you were able to get your car running again but the question is … If water in your gas tank was the problem, how did it get there?
Unless you left the fuel cap off and the filler door open I can’t understand how washing your car could have allowed enough (any) water to enter your tank, even if your drain plug around the filler neck was clogged up. The fuel cap is designed to be water tight. Just driving during a good rain would expose your car to more water than a car wash.
I suspect that there was enough condensation on the ignition system (almost always a failing cap or rotor) caused by your car wash that caused your no-start problem. And the time you spent troubleshooting water in the fuel tank was enough to let it dry out.
But hey, that’s just my guess 
If you did try a replacement rotor and cap and it still wouldn’t start
that would blow my theory.
I’ve taken the liberty to adjust the heading to read resolved so that people don’t have to try to add any further suggestions.
Ill have to find out. Distributor cap and rotor arm are brand new. My friend also told me that he had similar problem which was caused by a distributor moisture. But I do believe, its not my case. Engine started to run after i poured there a water removal, it was ca 23:30, quite cold outside. It started to run after several unsuccesfull attempts, as water which was already in the fuel lines had to go through at first… Also the white smoke blews from the air intake… My quess it was steam mixed with a fuel (it smelled so). But I cant tell you how the water went in, thats a question i would like to solve in several days… Maybe theres a hole somewhere, maybe the cap wasnt tightened… Dunno ať this point…
Gentlemen, I can tell you from my own experience with my '94 model that even with the fuel filler flap closed (not designed to be watertight, by the way) if the drain is clogged the area around the fuel cap will fill with water quite quickly. The gas cap will be submerged. To your point, Grooveman, the cap should be air and water tight but on a 30 year old vehicle, especially one with the original cap and sealing gasket, I question whether that seal is tight. I keep a coil of string trimmer line in the toolbox in my car just for clearing the drain when necessary.
So, after some investigation, i cant see any other chance that the water went in but filler cap. No seal/part cracks, water drain tube is perfectly clean… I cant assure if the cap was tightened or not, but the area was very probably simply overflooded by the water from the wash, maybe also the WAP pressure took its part… Ill keep my eye on this matter but seems to me as the only possibility…
Mike …
I hope you didn’t think that I was trying to state that the external fuel filler door should be waterproof, it’s quite obvious that’s not the case. I was trying to emphasize that even if the filler door was left wide open and water was sprayed directly on the cap (and even allowed to pool up around it) that still no water should enter the tank. Now that’s assuming that the cap has been tightened.
But even if the fuel cap was screwed on and not really tightened down I still don’t think enough water could enter the tank to cause the problem that Marek was experiencing.
I agree, its strange, but any other ideas? Stalled just after wash, blew white smoke out of air take, engine started to run just after pouring a water removal to the tank… Too many coincidences to bet on another cause…
Marek …
Just out of curiosity how long was it between when the engine stopped running and when you got it to start up again? I keep going back to the condensation shorting out your ignition system then drying out. I’ve had that very thing happen to my car so that’s why I keep leaning that way. White smoke coming out the air intake, how did you see that? Shouldn’t it be air tight from the front of the air filter on?
You never said if during your troubleshooting you replaced the cap and rotor and it still wouldn’t start.
If your Jag is back up and running then you’re in good shape … UNLESS … I’m right and it starts to rain really-y-y hard 
Cap and rotor was changed just prior that, during the spring service. So they are brand new. The smoke… Just exploded the opposite direction of air intake… from the engine to air filter, i thought something is on fire, but was just a steam (with a smell of gas) . Took filter away, left there just MAF sensor… And during my attempts of starting the engine, from time to time the mass of white smoke blew from air intake out straight to engine bay… All of that began ca 18:30 and engine started to run again ca 23:30… took quite a long time but it took just ca 15-30 min. from pouring the water remover. And, cant forget that miraculously after ca 2 hours from beginning engine started and run for ca 3 min for no reason without any trouble and than stalled again…
I didnt wash the engine bay and till the car wash, engine run fine for ca 5km that day and stationary for ca 15min the day before…
I simply have no other explanation… But I admit, its curious and strange…
Lets hope there wont be a rain tommorrow, i plan a trip of about 100km…
So, unlike Marek’s car, this thread refuses to die! Marek, what was the fuel level in your tank when this occurred, half, quarter, full? I’m wondering what happens when water enters the fuel tank via the filler, the car is stationary, engine not running (fuel not being circulated by the pump), and the fuel level is low. Anyone care to offer to run a little experiment on their car? I don’t wish to, in case you’re wondering. But I am curious.
Yes, there was more or less 1/3 of fuel. Was thinking of doing some experiment too… but to be honest, Id rather took another car today to fulfill my all job duties, as today is not the best day for doing experiments… well see later on…
Well, guys (if someone still interested ), I have yesterdays new find outs. I bought and installed new NKG lead plugs ca 2-3 weeks ago. I was a bit disappointed from the beginning, as the seal around plug holes doesnt fit perfectly. But ok, at least these were new leads, so I decided to give them a chance.
I started the engine yesterday night, just to check whats going on, and again, it began to run a bit tricky. No WAP wash this time And i found out, that electricity comes through isolation at the coil connection and at the points, where leads are connected to those leads plastic holders on camshaft cover… Well, of course Im ****, new OEM lead is already ordered from UK.
But, Im thinkig of - could this be the real cause of engine stall? If the leads were moisted from car washing… But again, what about the blowes of white/gas smoke out of air intake to engine bay….? These were quite a huge mass of smoke. I repeat, I did not wash the engine. Just a common wap washing of the car… could have this some relation to these lead seals of plug holes, that doesn fit well? How could a steam get to the air intake and how air intake could blow in opposite direction - out, not in… I cant imagine, how a slight moisture could go throug plug holes, I could understand this if the engine was overflooded by water, but certainly this is not the case…
Just to make clear, I did warm engine test compression also ca 2-3 weeks ago and the results were good, from 182-200 PSI.
When spark ignition of fuel (combustion point) comes out through intake section, this is usually a sign of cross firing - can be caused by breakdown of spark plug wire insulation on closest wires; carbon tracks on distributer cap from dirt, oil or water mist; condensation inside distributor cap - condensation is quick to form when temperature difference of two sections of air meets - such as the warm air from around the area of the engine and the cooler air from around the area of the bonnet (engine hood) when in rain, or washing the vehicle (very common during rain storms in Texas) - removing the distributo cap, drying it inside and outside, then replacing it, will usually allow restart - may seem not plausible to some, but have experienced this many times - look at how quick condensation forms on outside of glass of a cold drink in a warm atmosphere condition.