I am used to the sounds when I start my disco. But this morning and after work today when I started it there was an unrecognizable noise. It sounded like a high pitch vacuum cleaner wine. It last as long as the normal sounds and after about 2 min cuts off. No change in anything else with the car. Where should I start looking?

 

Could be your SAI (Secondary Air Injection). Mine does it for around 40 secounds or so after cold start up and is dependent on tempature. It helps in heating up your cat's. It is located on your firewall passenger side..black sort of a coffee can looking device with a tube coming off the bottom. At cold start have your hood open, and when you hear it go and listen to confirm. Good place to start tracking down this sound.

 

Yeah it's the SAI going nuts.

 

SO when I got home I opened the hood and went up front. I throttled up a bit to see if I could find the sound. It is a high pitched wine. It really sounds like it is coming from the throttle body itself. I am going to do an induction cleaning as well as clean the inside of the throttle body.

 

In the morning when it is cold I will open up the hood and listen. I did find a vacuum hose off on the right side of the black tank, right side of the engine, where the SAI tubes go. Maybe that was it.

 

Good find with that vacuum hose. Not sure how many miles but my SAI pump was much quieter after I replaced the filter under the top cap. You can make you own.

 

Mine SAI pump is pretty noise for about 40 seconds on a cold start. Can you tell us more about this filter? IS there a cap that just unscrews to access the filter?

Is this the filter?

 

That's it....I got some foam at the true value hardware store and made my own replacement. Have heard of those that have bought a lawn mower filter and cut it to fit also. While you have it off inspect the rubber mounts (3). My last order to roverparts I got a couple extra to have on hand. I have two Disco's to keep up with. Nice work.