Ok ive been having this problem since i got the car running, Its not a pop, but more of a loud cough type or sudden air release sound from the INTAKE when i shut off the car and it comes within a second delay of shutting it off. Its kind of hard to explain.
The car is a 1991 Integra LS, with a recently replaced b20b. It was kept obd0. It runs normal besides a little hesitation on take off which i assume is fuel Does anyone have any idea of what it may be? Any help is greatly appreciated.

 

Sounds like you timing is off. Check the mechanical and the ignition timing. That hesitation also sounds like a timing issue.

 

Let me guess... You have either a short ram intake or cold air one.

It is normal. Intake valve releasing pressure through the IM then TB then out the filter

You just don't hear it with the stock intake because of the baffles in it.

I think it is cool to shut off the car when someone is walking by and they hear the motor breath a sigh of relief. They turn and look at the car then you as you start to laugh at them.

 

I checked the mechanical timing before the engine was installed and it was perfect. Then the ignition when i got the engine in and running. So i dont believe it could be that.

Ya cold air, not really a fan of intakes besides stock, but came with the car. The thing is tho that ive never heard it on any other car with intakes before. And its pretty loud. Thats what just got me wondering. But seems like it could be normal as alot of people said it was. Just its never really been normal to me.