2000 XJ, 4.0, AW4, NP242.
I finally got around to doing the 0280155917 injector upgrade tonight after several months of procrastination. Everything seemed to go well until I got about four miles into the test drive.
What I have now is an occasional whistling sound - it's almost like the whistle of a boiling kettle only at lower volume. It only lasts for a few seconds, and the pitch remains constant regardless of road or engine speed. There are no other apparent symptoms related to it - just the sound. It doesn't seem to happen at idle, which is making it very difficult to track down.
There are no evident leaks at the injectors, either at the fuel rail or the head. Same goes for the fuel line connector at the fuel rail (which was not disconnected during the swap, FWIW), fuel damper, and fuel pressure test port. New O-rings were installed on the injectors. The throttle body was removed and does not show any evidence of having not properly reseated once reinstalled. CCV lines were not removed or damaged. Cruise control and cabin air vent selection work as expected, so I'm inclined to think it's not a vacuum leak from that system.
Any ideas? Apart from that noise, it's running great - much better than it has in a couple of years, in fact.
I finally got around to doing the 0280155917 injector upgrade tonight after several months of procrastination. Everything seemed to go well until I got about four miles into the test drive.
What I have now is an occasional whistling sound - it's almost like the whistle of a boiling kettle only at lower volume. It only lasts for a few seconds, and the pitch remains constant regardless of road or engine speed. There are no other apparent symptoms related to it - just the sound. It doesn't seem to happen at idle, which is making it very difficult to track down.
There are no evident leaks at the injectors, either at the fuel rail or the head. Same goes for the fuel line connector at the fuel rail (which was not disconnected during the swap, FWIW), fuel damper, and fuel pressure test port. New O-rings were installed on the injectors. The throttle body was removed and does not show any evidence of having not properly reseated once reinstalled. CCV lines were not removed or damaged. Cruise control and cabin air vent selection work as expected, so I'm inclined to think it's not a vacuum leak from that system.
Any ideas? Apart from that noise, it's running great - much better than it has in a couple of years, in fact.