Okay, so I've had this "problem" since I got dyno tuned. I installed my Walbro pump just a few days before heading to the tuner. I also upgraded to 750cc injectors there at the shop.

Here's the deal: After a short drive around the block and boosting a few times, I turn off the car's ignition and a couple seconds later I hear this loud "burp". It's almost like a deep toned 1 second belch, and it's definitely coming from the rear underside of the car. And it happens every time I drive the car.

I've tried tightening the gas cap in case it was releasing pressure from there, but it's not. I was even able to shut the car off and quickly put my ear next to the fillup hole....but that's not the culprit. Are there other ways for pressure to escape the tank?

So my real question is if anyone that has a Walbro with/without upgraded injectors is getting this too. I told my tuner about it and he said he's never heard of this happening. blink.gif dunno.gif

 

Maybe pressure leaking past the check valve? Does your fuel pressure fall off during the duration of the 'burp?' Pull the back seat and listen to the area of the fuel pump when the car is shut off.

 

Could also be too much pressure in the tank with a clogged/inoperative fuel vapor recirculation valve or a clogged vapor canister. Are you running a standalone ECU? If so do you have it controlling your vapor return valve?

 

Does your fuel system have a return path to the fuel tank?