hi everyone, on my X300 Jag, I noticed this.... If I dont start the car for a long time it starts up nice and smooth, but if I start the car up quickly after shutting it off, even after a couple of hours it has a jumpy or funny start, I dont know if thats what you would call but, but I describe it as being like a nasty start. It feels like the car shakes and it skips while its starting. Just does not have a smooth start at all. Like I said it only happeneds when the car is started more frequently, but if it sits over night and I wake up to start it, its starts smooth and fine. Any help would be appricated, thanks.

 

Is it possible that your car isnt burning all fuel off fully in the way that it is, while being driven? Perhaps the fuel pump continues to push fuel into your engine after the ignition is switched off? If the car is let sit overnight, this excess fuel might evaporate, thus eliminating the problem. However, if you start it immediatelly, it seems to be flooded, with the symptoms you describe, and will fire easily enough, as the engine is hot, but it will be lumpy as you describe. There is also a fuel pressure regulator, unless I'm mistaken, which could be suspect, leading to the same issue in much the same way. Whatever the problem, I'd put my money on fuel delivery or something very closely related.

Just my 2 cents worth. Hope it helps.

 

thanks for your response, what do you suggest I start on doing first? I dont wanna pour money down the drain. Any ideas?

 

Regarding the fuel pump (in the tank) it comes on when the ignition is switched on to position 2 and should go off when the ignition is switched off. You can get someone to switch on the ignition and you should hear the pump, maybe via the fuel filler flap or inside the boot/trunk. This way you can acertain whether the pump turns off as and when it should. If not, it may be as simple as a dodgy relay. Failing that, you get into more complicated territory that I'm not all too familiar with. Old cars used to have a reservoir in the carb, operated by a float mechanism, like you'd have in your cold water storage tank at home. A suspect float would lead to overfilling and flooding, with similar symptoms to that which you describe, so I'm thinking the effect may be the same, but by a different means. There is a fuel pressure regulator, which does exactly that, helping to increase/decrease fuel flow as needed under different loads and driving style. Maybe a search of the forums might throw up a lot more than I know! of course, I may well be way off the mark, but it's a bit of a process of elimination I guess, unless someone has the definitive answer.

Just as a possible indicator, try to let the engine idle for a few minutes before switching it off and then see how it performs. This might help to burn off any excess fuel (if there is any) without dumping loads more into the engine. Cant do any harm and may point you in the right direction.

Do keep us posted with any updates, and best of luck.