I just replaced the knock sensors in my 2000 XJR. This involved taking the whole supercharger off and reinstalling it (roughly 17 hours of work from beginning to end). I filled the coolant and have the throttle adjusted right. It started up, but I noticed several things:
1. I have misfire codes for all the cylinders except cylinder 1 ( codes p0300 through p0308, all except p0301)
2. The engine is running VERY rough. The whole car shakes at idle, which is typical of a misfire
3. there seems to be a whistling noise coming from the top of the engine, around the joint connecting the intake manifold to the plate on top of the supercharger

any help would be great. I’ve already spent hours on this car, and would love to have it finished

 

Stating the obvious but did you securely reconnect everything ?!

 

yes, I found a large instruction manual online, and followed it very carefully. I double checked every line, and made sure everything was back where it was

 

Agree with KC, sounds like some parts are loose. Also, how many ft. lbs. did you use on the sensor? They are somewhat fragile and require a specific torque...20Nm or 14 ft lbs
Also check your connection from the sensor lead, be sure it didn't get pinched or the pins didn't push out on the connection.

 

i have every hose out back where they belong, and every bolt back down to the right torque. yes, i have the knock sensors down to 20nm exactly, and theyre securely plugged in. i have double chekced and tripple checked.

 

I imagine that the air leak would be at those 2 large O rings where top lid connects to the heat exchangers. I know there was an update to the thin aluminum plate between the lid and H.E. where it has a ridge and the 2 large o rings have a receiving ridge for both of those to couple more securely. Check those first. If that’s not it, the other place could be where the brake booster plastic pipe goes into a brass piece under the throttle body. There’s an o ring inside that gets hard as a rock from heat cycles and the plastic retainer breaks often and failure from one or both of those causes air leaks. Of course there are other areas of concern but, those are the most often failed ones I come across on customers cars.