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You can also replace that entire monstrosity with a breather filter and attach with a hose clamp. The upside? You buy it once and clean/oil it every year. Any shop with 2 stroke engine parts will have one.
Good sir,
As these experienced gentlemen have noted, that noise that sounds like a vacuum cleaner is your SAI pump.
you'll see it on the passenger's side (USA).
It is off by itself.
There is a black plastic hoses coming out of it going to the back of the engine to a pipe I call the "wishbone" pipe.
As Spike said, that feed air into the engine on both sides.
That pump will come on if you have not used the Discovery 2 for a long time - say 24 hours.
Runs about 20 seconds and then goes off.
It will also come on once - in traffic for about 3 to 5 seconds once and a while.
Sounds like a shop vac.
Don't worry, this is normal.
If you disconnect it, you'll get powertrain codes with a lit check engine light.
Tried that.
So leave it connected.
Yeah its the SAI, secondary air injection, it forces fresh air down the exhaust and into the catalitic convertors to help them heat up faster, cold cats dont reduce emissons but hot cats do, so thats it what it is doing and that is why it only happens when cold.
Think of it as a black smiths bellows, he needs a hotter flame he uses the bellows to make the fire hotter, the SAI does the same thing.
That is also why you have the fast idle, a cold engine is very ineffcient.
Hi I noticed the noise a few weeks ago.when I first start up engine in morning, If I shut engine off and restart the noise goes away. Does the SAI pump make like a Jet engine turbine noise? and will replacing the filter fix the noise or does it mean the bearings are going bad? Thanks for your help !
The SAI pump is noisy in normal operation. That being said, since none of us can actually hear the noise you are hearing, we are all assuming that what you're hearing is the SAI pump. When they first came up with that particular system we had many complaints about it from owners (I was working at a LR dealership when that system was introduced). It was hard to convince someone that just plopped down a wad of money on his "high end" SUV that it was supposed to make that noise. The pump is only activated once after a complete cool down (usually overnight). If you shut it off and restart the command to start doesn't reoccur. (seems like a stupid strategy to me since the excessive emission conditions that the pump is supposed to be addressing hasn't changed, but I suppose the system was installed to satisfy the EPA at the time)
The filter is not the only part that can caquse a noise. Sometimes you will have to open up the motr and clean out any dirt, rust and moisture that may have built up.
Great info on here. I'm going to work on the SAI pump this weekend while replacing the vacuum lines. The filter is probably gone because it's sounds like a loud Hoover vacuum cleaner.
I'll report back and post pics of the process.
Disco Mike
Could you describe more in depth on you mentioning the oil light coming on ? Mine comes on temporarily but shuts off 2-3 secs after starting . What's the significance?
The pump is only activated once after a complete cool down (usually overnight). If you shut it off and restart the command to start doesn't reoccur. (seems like a stupid strategy to me since the excessive emission conditions that the pump is supposed to be addressing hasn't changed, but I suppose the system was installed to satisfy the EPA at the time)
