Hey folks, I ran with a pretty loud exhaust for a while and now I'm back to stock exhaust and the secondary air pump noise upon cold start seems unusually prominent, sounds like the pump is pushing air pulses right out into atmosphere from the sound of it, after appr 1 minute it goes away.

I know it's normal at cold starts with raised idle, timing change which also changes exhaust pressure + rich condition upon cold start, with secondary airpump running as well, to heat the catalysts quickly, I just can't remember if the "airleak pulse sound" is supposed to be this prominent.

Car runs super great, no leaky sounds after that first minute, boosts quickly and holds boost relentlessly.

How do your guys' cars sound on cold start, just kind of semi bad (this is what I remember) or do they sound like "air leak" style pulses?

Thx for chiming in.

 

Just had some engine work done and this pump wasn't connect correctly thus never turned on. Got CEL within 5 mins of my house- brought it into shop and quick fix along with a few other tidying up bits.

Mine just has the high pitched wine and no pulsing noises. Turns off after a few mins and don't hear it for remainder of the day. Think the computer is only checking that it turns on within X amount of time and was told you are spot on with its function. I'm also back on a stock exhaust (with wholes drilled) so can hear it again!

 

Thanks for the input.

I'm going to start the pump with the Durametric tool and see if I can locate the noise, there might be an air hose popped or bust, it's just a little too much pfft-pfft-pfft-pfft noise going on to believe it's up to OEM standard.

 

Resolution: Secondary air pump was not the cause, it was an exhaust manifold gasket leak.

To locate the noise I jacked up the car and had a 2nd person start the car which allowed me to locate the sound by listening underneath and I found it.



Cleaned it up (fine sandpaper) and used a new gasket (thx Pelican Parts) to install it. No leak anymore. Engine sounds great and tight on startup again, like a Porsche should. No ugly "frt frt frt".

Background to leak:
When the engine appr 3 seconds after initial startup goes into cat-heating mode the exhaust pressure increases which caused the old gasket to leak. When the car got hot and the metal expanded, it would seal itself.

That side exhaust manifold I had to remove earlier this year during a turbo swap although it wasn't planned, so for that time I had to bolt it back with the same old gasket. Initially there was no noticable noise, but over time the old gasket didn't hold.