Started the car, and a very noticeable hissing sound was coming from the rear of the car. Got down to listen and it seems like it could be coming from the fuel tank. I will rack it up tomorrow, but in the meantime I figured I would see if anyone else knows what it is.

Turn on the car, constant hissing pretty loud, then stops like it's controlled. No idle issues or CEL's, and no pending codes either. It is loud enough to be very noticeable, and it just started today. Only mod back there is a Blaqops Fuel Pump Kit. Thanks

 

could it be an exhaust leak? check to see if you can tighten the bolts going into your muffler

 

did you just recently install the fuel pump? maybe that is causing the sound and you just now noticed it ?

 

I hear too. Especially from a long drive.

 

if you recently installed a walbro fuel pump that is what you are hearing

 

No I know what the walbro sounds like. I promise . I have used many of them in gutted cars. They whine like a *****. This is different.

This is EXACTLY like a hiss or air leak. 20 seconds of loud ssssssssssssss. Then it stops like it is controlled by something. I am racking it up Monday morning and I will let you know what it is if I find it. It is when the car is running only. The pump primes, car starts, hissing starts, 20 sec later...stops.

P0139 code just hit. First time throwing that one. I usually throw P0140. Related to the hiss? Who knows lol

 

I have had the pump for a month or so. I noticed it when I started my car and my door was open. I thought I had a hole in my tire. Sounded just like letting air out of a valve stem. Got down by the rear tire to check and it was coming from the tank. The walbro whine is there...can't miss it. Definitely different.

 

Maybe your car has a mind of it's own and the rear windsheild wiper fluid pump is running. Doubt it but I have seem stranger!

Mikey

 

you sure its not the evap system purging or pressurizing the fule tank??

 

HAHA...the car definitely seems to have a mind of it's own. My speakers go in and out whenever they want as well. Good thing I just bought this car to go fast.

To the comment about the EVAP. That's what I assume it is but I haven't racked it, nor have I looked at the EVAP schematics yet. Not sure where all of the components are but I will find out tomorrow.

 

did you ever figure this out? my evo 9 does the same thing seems to have gotten louder and more frequent since i did intake. It definatley comes from the engine bay and goes for about ten seconds on my car as soon as you start the car and start rolling. Sounds like it may even be coming from the intake filter itself?

 

Doesnt the AYC make a sound when you start for the first time? Mine makes a similar as long as I can remember. Been running strong for 16 mths now.