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What am I hearing when my car starts up in the cold?

ElectricEye

ElectricEye

Autocross Newbie
canucklehead said:
what you hear is the fuel pump. I hear it too when it's cold out
Click to expand...

The fuel pump is that tock, tock, tock coming from the right rear of the car.

Theses are whirs, bleeps etc., coming from somewhre within the dash/cowl area.
 
Modshack1

Modshack1

Go Kart Champion
HailToTheKing said:
yeah I get this too on cold starts in the morning. it's like a muffled we-ooh sound that goes on for maybe 5 minutes then stops.
Click to expand...

Yeah...It's the SAI pump. On the old 1.8T these would start to sound like a jet engine when they got old!
 
Modshack1

Modshack1

Go Kart Champion
ElectricEye said:
Theses are whirs, bleeps etc., coming from somewhre within the dash/cowl area.
Click to expand...

Yes. It's an air pump. The entire system is triggered by temps below a certain point. There are solenoids (valves) that control the pumping of air the into the exhaust area (usually called the Combi Valve). Since the temps also trigger an enrichening system to fire the car up when cold, The SAI system injects air downstream to lean the burn and bring the Catalytic converters up to temperature faster. It's part of the California emissions requirements as well as the other 10 or so states in the Northeast that require the same emissions system.
 
ElectricEye

ElectricEye

Autocross Newbie
Modshack said:
Yes. It's an air pump. The entire system is triggered by temps below a certain point. There are solenoids (valves) that control the pumping of air the into the exhaust area (usually called the Combi Valve). Since the temps also trigger an enrichening system to fire the car up when cold, The SAI system injects air downstream to lean the burn and bring the Catalytic converters up to temperature faster. It's part of the California emissions requirements as well as the other 10 or so states in the Northeast that require the same emissions system.
Click to expand...

That makes sense, solenoids opening and closing - I can picture that going on where the sound emanates from. :cool:
Thanks!
 
S

sskamboj

Ready to race!
glad im not the only one that heard it... definitely happens a lot during the cold, even when the engines warm. Thanks for the info Modshack, thats a relief.
 
allset

allset

Go Kart Champion
Ur prob CBFA
 
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