topnotchrally 141 Report post Posted March 16 This is my beloved 1999 523iT manual. The engine light has come on P0170 P0173, fuel trim malfunction. Clearly there's a vacuum leak somewhere under the intake manifold. Anyone had this before? Can recommend where to look? I fear I will have to remove the intake manifold to find it. I had something like this before, it was the hose on the top that was leaking, fixed that about 10 years ago. The 'wailing' sound is there at the start of the video but is more obvious after I blip the throttle and it comes a back. It's quite loud, sounds like a vacuum cleaner, oddly enough. M52vac-leak.mp4 Quote Share this post Link to post Share on other sites
Eagle 1725 Report post Posted March 17 CCV diaphragm or plastics pipes have failed. Smoke machines can be had for less than $200 on aliexpress etc if you cant diy one, no reason not to own one. Quote Share this post Link to post Share on other sites
