I have a fairly strange problem with my 2010 Jaguar XF 5.0 NA whereby occasionally it would have trouble starting (cranking with no stumbling, as if it was getting no fuel). It would randomly start up after retrying many times and would in fact, drive normally. Power is good, it will idle and no unusual sounds that I can tell when the car is up and running. However, recently the car just cut out while driving and threw the P2279 code (intake air system leak). It is now nearly impossible to start. I have done a preliminary check on the intake and nothing seems amiss...

Any suggestions as to where to look for this leak or is this another problem I am facing? I'm going to assume that it is some sort of vacuum line that has been punctured since the car drives fine otherwise... All opinions on the matter are greatly welcomed!

 

So I just had an explosion happen underneath the hood. I checked all the vacuum lines leading from the brake master cylinder and leading around the engine to make sure everything was intact and in good condition. Everything seems fine with no cracks or holes. I went to see if I could start the car and after a few moments of turnover, part of the rear engine exploded. I saw large amount of smoke and a slight fire. Luckily it wasn't gas related as the fire immediately subsided but it seems there was an electrical fire of sorts. The pressure of whatever blew took out my rear coolant pipe (that was just replaced about 6 months ago!) and a few other plastic parts which I have yet to identify. How in the hell a p2279 code could lead to an explosion is pretty wild.

I'm assuming whatever pressure/vacuum was built up, and destroyed the electric sensors causing an explosion but it seems there must have been something else going on... Any suggestions or opinions are greatly appreciated.

 

Oh, I think it very much was gas related. Sounds like a gasket leak and too much air in the intake manifold, an increase in fuel and a backfire. P2279 is the imbalance of air with the throttle in the middle, sounds like it starts lean and cranking adds more fuel to create the rich environment. Very common in carbureted systems but I have seen it with fuel injected as well.

 

Thanks for your insight! Just to confirm, you feel the leak was after the throttle body? In other words, within the intake manifold? Would you guess that this was the intake manifold gasket leaking or perhaps one of the vacuum lines leaking just behind the intake manifold? I'm asking because I noticed a mouse nest and bits of the engine bay fibers being eaten and I'm trying to pinpoint what is likely the cause before taking everything apart.

Btw - what are the chances that the engine is okay aside from the wiring loom being burnt along with the intake manifold blown out?

 

So I still have issues with this car after I purchased a whole intake manifold (used) and replaced all of the 8 gaskets. The coolant pipe replaced was replaced and everything is pieced back together as it was. Unfortunately the car will not start when turning it over (as it did before). I'm afraid to keep cranking it, given that the last time I did that, an explosion occurred.

I did not notice anything unusual, cracked or broken in regards to any of the breather pipes etc... but perhaps I missed something? Does anyone know if there are more common problematic area's that I should check?

 

Start with the basics?
Do you have fuel? Does it start if you give it a shot of starting fluid?

Does it have spark?
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