Air Injection Pump
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503wtq Boosted Bimmer
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From: Los Angeles, California
Air Injection Pump
It's 10am in the morning and about 60F outside. I walk outside get in my car and start it. What do I hear "weeeeeeeeeeeeeeeeeeeezzzzzzzzzzzzzzzzzzzzzzzz z" for about 1 minute. It has been this way for as long as I can remember, but it seems pretty damn loud. Is that normal?
For those of you who don't know, the secondary air injection pump circulates warm air from the exhaust into the intake to help meet emissions during cold starts.
For those of you who don't know, the secondary air injection pump circulates warm air from the exhaust into the intake to help meet emissions during cold starts.
Yep, mine has always done it. The colder it is when it is first started, the longer it seems to run for. I have not timed it to see if this is actually true, or if it simply runs for a set amount of time at Start-up. Maybe Zoom or RotaryGod knows for sure. I typically wait until it stops to move the car, I use the wheeezzz stop as my warm up guide, once it shuts off, I keep the RPMs under 4k until the temp is up to the middle and then drive normally.
^^ This is exactly my warm-up schedule and what I recommend to every one.
The amount of time the pump runs does change according to temp, though I haven't seen any data in the shop manual to indicate what criteria the PCM uses to decide how long it should run, if at all.
30 seconds is typical.
The amount of time the pump runs does change according to temp, though I haven't seen any data in the shop manual to indicate what criteria the PCM uses to decide how long it should run, if at all.
30 seconds is typical.
It sounds like a mini vacuum cleaner. Next time your car is stone-cold, pop the hood before you start it and get out and listen to the device just in front of the windscreen washer bottle.
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