Question: Can someone post a pic of how the insulation material between the supercharger and the valve cover on the passenger side is supposed to sit? Mine hasn't been right since the indy mechanic pulled the supercharger the first time, and I've finally found it to be the root cause of my intake leak (more below). I did the supercharger again myself a few months back, but didn't have a reference to lay this part out right since the tube was run wrong before and has now shrunk some.

More info: About a week ago when I started the car it idled pretty high (2k) for a bit. I plugged the scanner in later, and fuel trims were 50 on both banks at idle with lean codes pending. I've dug into it more, and found out that the cause seems to be this heat shield material covering the hole in the center of the valve cover breather. This took a while to trace down, but I'm confident it's related to that breather now. I assume it needs that hole to operate, guessing that allows the rubber membrane to pull down and seal off the cover so it doesn't suck air in as mine was. If someone knows different and thinks mine is broken let me know, but once I got that little hole cleared my fuel trims quickly worked their way back to normal. If I let the material fall back on it, I heard it start leaking again and fuel trims shot back super high.


breather with heat shield material covering center hole that lets air in behind rubber membrane

Vent hole I believe is being blocked, causing seal below to not get pulled down and therefore causing intake leak

 

After further investigation, the membrane for the breather had a crack and was leaking air so that's why covering the hole impacted it. I was able to change this without really taking anything off, although it's definitely a trick. I used a pick set to break about half the tabs off the old cover, then was able to push it off. My fuel trims are down from 50 to 5 at idle, so much better. Might still have a small leak at one of the breather hose o rings, but that can wait for warmer weather.

 

Any vendor/part number information you'd like to share?

 

Here's what I got. It's not the jag part, but I wanted to get it fixed quick so prime shipping was quite handy. It fit on well and has good reviews so far.

 

I'm thinking that's what's causing my lean codes and misfires as well. This seems to be a more common problem with the Land Rovers for whatever reason. What's the mileage on your engine?

 

Around 85k. Do you have a scanner you can look at fuel trim on? Mine changed significantly if I covered the little hole in the middle, and I could also hear the air flow change. That may have just been a trait of where mine ripped though. I was thinking another way to isolate would be to disconnect the tube to that valve cover and plug up the port for it on the throttle body to see if the trims were good then. Obviously wouldn't leave it that way, but it might help narrow down.

 

That's an interesting idea but I've already got the replacement pcv parts in hand and ready to go this weekend. My fuel trims are nutz. They start off around 30 and slowly climb to around 80 where the engine then starts to misfire. I was running out of ideas until I ran across the various threads on Land Rover forums. I'm glad to see this fix worked for you.

 

Ah nice. Is it on a 3.0 supercharged as well? And are you doing both sides or just one? I only did the passenger, so not sure how hard the drivers is to get to

 

No, I've got the 5.0, so there's two valves on the passenger side.

 

How'd yours end up?

 

I experienced the same problem and used the fuel trims and throttle body cleaners to pinpoint it.. Good job!

Gus
JagRepair.com - Jaguar Repair Information Resource