Hi ClubLexus. Just got my IS500 and noticed when the engine is cold, it makes a whooshing/compressed air sound from 2500-3000 RPM under moderate throttle. It doesn’t make the sound outside that range, when the engine is warm or when lightly accelerating.

im going to take it to the dealer but figured I’d see if anyone else is experience this so I can help the technicians narrow down what the issue is. Thanks all!

 

Mine does this only if I start giving it moderate throttle when it is still cold. Once the engine is warmed up, the sound goes away, at least, on my car. I wondered what it was, but it has been this way since new and not gotten louder/more noticeable over time.

 

The aircleaner box has some flaps/valves that open under certain conditions, what you're experiencing might be one of those conditions.

 

Mine has the same sound when the engine is cold and I am in a rush. It disappears when the car warms up.

 

See attached link for more info. The current sounds you/we hear are very normal: Intake sound

 

Same sound on all the IS500s I owned only when cold.

 

UPDATE: After testing driving with two technicians, I have been told it is the High Pressure fuel pump which works in conjunction with the direct fuel injector when the engine is cold. Once the engine has warmed up, it switches to port injection which uses the low pressure fuel pump. This is why I only heard it when cold. The compressing/whooshing sound was not out of the ordinary and sounded normal to the technicians. Thanks all for your feedback!

 

OK... So, what this implies to me is that the direct/port injection strategy is different when cold versus warm... Which makes sense, I suppose. But, at moderate throttle between 2000 and 3000 RPM, it's direct injection when cold and port injection when warm? Doesn't it also depend on how much load there is? So, like, if I was holding constant RPM and suddenly gave it a bootful of throttle, I should hear this noise?? This is all very odd. lol

 

Yes that is exactly what the the technician told me. When the engine is cold: direct and high pressure fuel pump. When the engine is warm: port and low pressure fuel pump. He didn't say anything about load. I don't think it would alternate between the two depending on load. I'd assume youd still hear it if the engine was still cold and the high pressure pump was still in use. However i typically dont go past 3500ish RPM until the engine has warmed up a bit so I cant confirm.

 

Hm, but we absolutely would want direct injection at higher engine loads for maximum power. In fact, I am pretty sure I read somewhere that that's how this works...

Anyway, I found a paper where the D-4S system was analyzed in the 2GR-FSE, and it says that, on partial load, BOTH injectors are used to create more even air-to-fuel distribution in the cylinders. Interesting stuff. I don't have time to read it all right now, but to me, this makes more sense.
https://repozytorium.biblos.pk.edu.p...ion_system.pdf

 

Just heard this sound for the first time the other day. Most of my cold engine driving is very mellow. Caught me by surprise, but fortunately I remembered this thread.

 

I happened to catch this noise tonight while driving home even though I'd been driving for over 30 minutes. The car was definitely fully up to operating temp.

 

Do you hear this and the chirping sound inside the cabin with windows up? My windows are usually up and I don’t hear anything .

 

Windows up. Incidentally, I did hear the chirping sound when I was at a stop sign briefly. It had gone away by the time I came to another stop sign.

 

Modern engines make so many noises these days it’s hard to tell what’s normal. Unfortunately Lexus service departments don’t seem to know either so that doesn’t help us as owners.